April 1, 2004
Hyatt Regency Crystal City at
Ronald Reagan Washington National Airport
2799 Jefferson Davis Highway
Arlington, VA 22202
COUNCIL MEMBERS PRESENT
Leon R. Kass, M.D., Ph.D.,
American Enterprise Institute
Benjamin S. Carson,
Johns Hopkins Medical Institutions
Rebecca S. Dresser,
Washington University School of Law
Daniel W. Foster, M.D.
University of Texas, Southwestern Medical School
Francis Fukuyama, Ph.D.
Johns Hopkins University
Michael S. Gazzaniga, Ph.D.
P. George, D.Phil., J.D.
William B. Hurlbut,
Peter A. Lawler, Ph.D.
Gilbert C. Meilaender,
Janet D. Rowley, M.D.,
The University of Chicago
Michael J. Sandel,
Diana J. Schaub, Ph.D.
James Q. Wilson, Ph.D.
WELCOME AND ANNNOUNCEMENTS
CHAIRMAN KASS: Would members please take their seats, so
that we can begin?
Good morning. Welcome, members of the Council, to this the
16th meeting of the President's Council on Bioethics, the first of
our second term.
Welcome also to members of the public. We're delighted
to have you with us.
I would like first to recognize the presence of Dean
Clancy, the Designated Federal Officer in whose presence this is a
legal meeting. Not everybody here will recognize Dean Clancy, who
has, in honor of his forthcoming 40th birthday, emerged from hiding and
shed his whiskers.
Dean, on behalf of all of us, a hearty congratulations.
I would also at this time like to introduce to the Council
our three new members. To my left, Dr. Ben Carson, who is Professor
and Director of Pediatric Neurosurgery at Johns Hopkins Medical
Institution; two to my right, Peter Lawler, who is the Chairman of the
Department of Government and International Studies and the Dana
Professor of Government at Berry College; and three to my left, Diana
Schaub, who is Professor and Chairman of the Department of Political
Science at Loyola College of Maryland.
Welcome to the three of you. You've joined an interesting,
sometimes contentious, but I would like to say civil and productive
group. We are very much looking forward to working with you
over the coming months and year.
SESSION 1: BIOTECHNOLOGY AND
PUBLIC POLICY: COUNCIL'S REPORT TO THE PRESIDENT
CHAIRMAN KASS: The main purpose of this
first session on biotechnology and public policy is the release
of the Council's report to the President, "Reproduction
and Responsibility: The Regulation of New Biotechnologies,"
copies of which members should have at their places.
The procedure for this session is as follows. I will make
some relatively lengthy remarks introducing the report and trying to
summarize its contents and conclude with some statements of what I
regard to be the report's major achievements and caveats.
Individual members who have expressed the wish to comment
will then do so. I think by my list we have either eight—we have
either nine or 10 such people who want to say something briefly, two to
There are, I believe, some members of the public with whom
we have consulted over the course of writing this report who have
submitted personal statements, and some of them I think would like to
read them, and then the floor will be open for comments and questions
from the media.
Let me begin. The report that we release today,
"Reproduction and Responsibility: The Regulation of New
Biotechnologies," examines policy and regulatory issues that arise
at the intersection of assisted reproductive technologies and genomic
knowledge—an increasingly busy intersection and one that raises a
daunting array of opportunities and dilemmas for patients suffering
with infertility and for doctors and researchers.
It raises the prospect, but also certain kinds of risks, of
new life for children born with these procedures. And it has certain
social implications important for regulators and policymakers and,
indeed, for the American public as a whole.
The report is the product of a two-year process for us, which
really began at the very first meeting of this Council in January
2002 when, you will recall, Frank Fukuyama expressed the hope that
as one of its projects this Council might explore how new biotechnologies
are regulated in the United States and perhaps recommend some ways
that regulatory practices could be improved, given new technologies
and the new sorts of challenges that they represent.
With time, and given the other projects in the last term of
the Council, the term of which this report is, in fact, the final
product, we put that focus of regulation on the more particular domain
of assisted—of the issues that arise at the confluence of assisted
reproductive technologies, genetic testing and selection, sex
selection, and embryo research.
In the cloning report published in July of 2002, the
Council stated frankly that further inquiry into the current state of
regulation in this entire area was necessary. And since that time we
have, in fact, been taking this up.
We've devoted a very significant amount of our time to
this project. We've had 26 public sessions devoted to it.
We've had presentations from a great many experts and stakeholders,
including patient groups, professional societies, government agencies,
policy experts, and people who are involved in the regulation of these
areas in other countries.
We put out a call for public comment and received valuable
written comments from dozens of groups and individuals around the
country, and in the report we list and acknowledge the help that we
have received from all of these people, and we are very grateful to
those present and those not present for your help.
The Council, with the help of the staff, produced this—took all of this in and produced the report that we have before us.
The bulk of this report is, in fact, a diagnostic document laying out
the present state of regulation of these fields to the United States,
public and private, governmental and professional, federal and state.
And it concludes with some modest interim recommendations for how a few
outstanding problems might be dealt with in ways that we think should
be agreeable to just about everyone involved.
We have not at this time recommended major institutional
reform or major institutional innovations, because a great deal of what
we have found in our review of this field is that much remains to be
known. We need more basic data regarding current practices and their
impact to find out how big a problem this really is.
We need to figure out the effectiveness of the rules and
regulations that now exist, both governmental and professional, and we
need to explore the costs—the benefits and the harms of any kind of
new innovations that anybody would like to propose.
Before going on, I want to say—I want to say something
about the staff work that has gone into this. I mean, the members have
contributed enormously, reading many, many drafts. But the real credit
for this report belongs to the staff, and especially to Carter Snead,
our General Counsel, who has taken the lead on this project.
And let me say that this staff has put out five volumes, four
reports and an anthology, in 26 months. They are extraordinarily
devoted to their work, top to bottom. The morale in the office
is extraordinarily high, because people like what they do. They
work well with one another. They believe in what we've done.
And I would like at this point simply to express my
profound gratitude on behalf of all the members to the entire staff,
top to bottom, for what you've done. So thank you very much.
Before I get to the actual content of the report, we should
point out that people who read the transcripts of our meetings and the
discussions that produced this report will give you a sense of the fact
that this Council has deep disagreements and differences.
And if you read the recommendations in this report, you will discover
that—which are made unanimously by this Council—you can see
how people who nevertheless disagree profoundly on some issues can
nevertheless find some common ground. And I think this—as I will
say at the end, I think this is really one of the great achievements
of this report.
And I hope it offers an example to policymakers about the
way in which, notwithstanding our continuing disagreements and
arguments, we can find common ground and even seize it as we continue
to debate those other things that don't lend themselves so easily.
I think most people are going to be interested, at least on
this occasion, in the recommendations. But before I get to that, let
me give you a kind of overview, a guided tour to the whole document, so
that you can have a sense of what's in the report.
The report is in three parts. There's an introduction;
Part 1 is the diagnostic survey, which is the bulk of the report; Part
2 explores policy options and concludes with recommendations.
The brief introduction lays out just why the Council has set out
to explore this area and what we take to be some of the most important
concerns and values that should guide anybody interested in exploring
regulation—from the health and well-being of infertility patients
and their children, to the desire to seek new therapies for the
suffering and the sick, to the responsibility to protect and respect
human life, and to a number of other critical issues of privacy,
equity, freedom, and dignity.
The report is guided and motivated by all of these, and the
introduction lays out these values at least in some beginning detail.
The great bulk of the document, to repeat, is devoted to a
diagnosis of current regulatory practices in different areas having to
do with the intersection of assisted reproduction and genetic
knowledge. Assisted reproduction is not, as such, our focus, though we
have looked at how it is currently regulated in the course of our
diagnosis, because assisted reproduction is, in practice, the necessary
gateway to all of the newer technologies present and projected that
will affect human reproduction.
Any oversight or regulation of the use of genetic
technologies in human reproduction will, therefore, necessarily depend
on the systems that oversee and regulate assisted reproduction itself.
Therefore, in Chapter 2, we begin by looking at the state of the art in
assisted reproduction, laying out in general some relevant ethical
issues that need to be addressed, and then examining in great detail
the variety of ways in which the practice is regulated.
And by the way, "regulated" here is a very
loosely used term. I mean, it doesn't mean law and proscriptions.
It means anything that affects the practice by deliberate design,
professional guidelines, and norms primarily preeminent amongst them.
This three-part approach—techniques and practices, some
ethical questions, and exploration of existing regulation—is the
model for how we examine the rest of the techniques that we take up in
the diagnostic portion of the report.
In Chapter 3, Genetic Screening and Selection; in Chapter
4, Modification of Traits and Characteristics, where it's important
for me to point out that in this report, as the Council has done
before, we point out that significant genetic modification of traits
through genetic manipulation is simply not in the offing in the
In Chapter 5, research on in vitro embryos; in Chapter 6,
some issues of commerce that arise in the various fields and that carry
their own regulatory challenges; in Chapter 7, we briefly conclude and
summarize the diagnostic section.
All of this is brought together in the report's eighth
chapter, which offers in a succinct and organized form the
Council's findings in the light of the extensive diagnostic
survey. These findings you can find listed in the Executive Summary,
Roman Numeral pages 43 to 44.
And I won't read them all here, but one of the things
that we have discovered is that there really is a lack of basic data on
the effects of assisted reproduction and associated technologies on the
health and the well being of the women and the children involved.
The findings show that right now, although there are
various kinds of regulatory practices in place, there is really no
uniform comprehensive or enforceable system of data collection,
monitoring, or oversight for the biotechnologies affecting human
reproduction, and that there is minimum government involvement in the
regulation of these technologies with the notable exception of gene
transfer technologies, where regulation is really quite effective
through the RAC and the NIH.
There is, however, fairly extensive professional
self-regulation of some of these practices, even if compliance is
voluntary. We find that there are no uniform rules regarding access to
assisted reproduction or insurance coverage, and with regard to the new
technologies we find that experimental technologies that work move very
quickly into general practice where their use becomes widespread pretty
rapidly, though not necessarily with prospective studies to study their
These are some of the findings that emerged from the
Council's review of the field, and it's important to understand
that none of them mean simply that some particular action is called
for. In some cases, what we have found is that the field does not
differ from how things are really done in medicine in general, and in
some cases we have not found that the present situation really calls
In short, this preliminary review and diagnosis has not led
the Council at this stage to make any sweeping suggestions for
institutional reform or institutional change. Nevertheless, we thought
to at least advance the discussion, in the ninth chapter we set forth
certain kinds of policy options that might be available, just to show
the range of the options that exist, or that have been pursued
elsewhere in the world or in other fields.
We lay these out to offer a sense of the range of what
might be done rather than as examples of what we now think should be
done. And we make it quite clear that, given the preliminary character
of this report and the fact that our review of the field has turned up
a number of areas where crucial data are still lacking, the Council is
not prepared to recommend sweeping institutional reform or innovation.
Instead, members have sought—in the interim while the conversation
and discussion proceeds—we have tried to see whether we could
agree on some modest measures to alleviate some clear and significant
present problems, including especially the lack of information on
certain key practices and their consequences.
And these measures are laid out in the chapter's tenth
and final chapter, the recommendations chapter. And in that chapter we
offer interim measures that we believe should be adopted immediately,
and these recommendations, I repeat, have been offered by the Council
The strategy here in the recommendations chapter was let us
set aside for the time being those things on which we disagree, and let
us see whether we can in the interim, as modest temporary measures,
make proposals that all of us could stand behind.
The recommendations fall into three categories, and for those who would
like to follow, you can find these recommendations in the Executive
Summary. The defense of them is in Chapter 10, but if you want
to see them succinctly they appear in Roman numerals 46 to 49 of
the Executive Summary, in the front matter of the book.
Three categories of recommendations—the first are federal studies,
data collection, reporting, and monitoring regarding the uses and
effects of these technologies. Here we are recommending federally
funded studies to examine the impact of various assisted reproductive
technologies on the health and development of children born with
their aid and on women who undergo treatment.
We also recommend a few discrete steps to strengthen and augment
the one existing piece of federal legislation—the Fertility Clinic
Success Rate and Certification Act—the Act which provides information
to people seeking fertility treatments.
These measures we recommend to help bring the law up to
speed with new technologies that have developed since the law was
enacted and to better protect consumers and patients. They are very
much in the spirit of the law that already exists on this subject, and
these recommendations have been drafted with—in consultation with the
professionals who work in the field.
Let me emphasize one item here that I think is of special
interest. This Council has taken special note of the importance of
learning about the implications and effects of these technologies on
the children who are born with their aid.
There have been no longitudinal prospective studies of the children
born as a result of assisted—with the help of assisted reproductive
technologies—despite the fact that these practices have been flourishing
since 1978. There are lots of reasons for this. We're not
second-guessing the failure to do so. There's questions of
funding. There's questions of privacy. There are all sorts
But one of the reasons I think that there hasn't been this
much attention is that the profession of—the reproductive endocrinologists—have, for perfectly obvious reasons, regarded the infertile couples
and the adults as their primary patients. When the pregnancy is
achieved, the patients are turned over to the obstetricians, and
it is only late in the day that the pediatricians get into the story.
One of the real important contributions, I think of this
report, is to shine the light on the importance of attending to the
children and learning much more about what this means for them now and
in the future.
The second set of recommendations are addressed to the
professional societies and the practitioners in the field of assisted
reproduction. There is a fair amount of regulation that is
self-regulation in this area, as there is in medicine in general, but
we have suggested a few ways in which that self-regulation might be
improved for the benefit of all involved.
These include a strengthening of informed patient decisionmaking,
improved enforcement of the societies' own existing guidelines,
and suggests to them development of additional standards for human
subject protection. And these you could find on page 47.
The third category of recommendations, the ones that are
likely to get the most public attention, consist of a few targeted
legislative measures. In the course of our review, the Council has
observed the fast-moving pace of research and innovation in this
field. We have noticed that there are various kinds of values and
goods connected with human reproduction that we hold dear and that we
would like at least to protect.
And since we do not know whether or when or even—whether
or when any kind of more formal regulatory or oversight mechanism would
be developed in the future, we thought that since we are making this as
an interim report we ought to think about whether there are interim
measures that we could suggest that could at least set certain kinds of
boundaries to protect things that we hold dear while the public
deliberation goes on.
And we have decided that there are certain areas that need
special attention, and we recommend in this report that Congress should
consider some special targeted legislative moratorium.
The report itself in Chapter 10 offers extensive discussion
of the reasons for these recommendations and gives the reasons for—and it also discusses the aims that we think that these targeted
measures should serve. And these are found on pages 222 through 225,
227, of the report.
These recommendations are in order to help preserve a
reasonable boundary between the human and the non-human, or between the
human and the animal in human procreation, to preserve respect for
women and human pregnancy, preventing certain exploitive and degrading
practices, to show respect for children conceived with the aid of
assisted reproductive technologies, securing for them the same rights
and human attachments naturally available to children conceived in
vivo, and to set some agreed-upon boundaries on how embryos may be used
and treated notwithstanding the fact that we have lots of disagreement
in this Council about the embryo question in its entirety.
Returning to the particulars, therefore, with respect to
the first point, the Council calls for the prohibition of the transfer
for any purpose of a human embryo to the body of any member of a
non-human species for purposes of research to prohibit the formation of
hybrid human-animal embryos by fertilization of human egg and human
Under the second category, that there should not be
pregnancies initiated for any purpose other than to produce a live-born
child. That is to say, pregnancies are not for the purpose of
experimentation or for harvesting body parts.
With respect to the child, we call for a proscription on
conceiving a child by any means other than the union of egg and sperm,
where conceiving a child is carefully defined to mean the creation of
an embryo ex vivo with the intent of transferring it to a woman's
body to begin a pregnancy.
I'll say something more about this, but it has been
noted that one of the practices that this would include would be, of
course, the cloning of an embryo with the intent to transfer it. And
so with respect to cloning, this recommendation is really a restatement
in greater detail of an earlier Council position unanimously opposed to
cloning for producing children.
The differences, of course, on the cloning for research remain,
and I will allude to that further. We have also called for a prohibition
on conceiving a child using gametes obtained from fetuses or derived
from embryonic stem cells, or by fusing blastomeres from two or
more embryos. No child should be able to say, "My mother or
father is a fetus," "an embryo," or a "stem
cell," or that "I come from fusions of two or more embryos."
On the embryo research question, notwithstanding our
continued deep differences, we have called for setting a limit on the
use of—a prohibition on the use of embryos in research past a certain
stage in development—again, a position that many sides, as they
presented testimony to us, said that would make sense. And our
approach here is also different from that proposed in other countries
or proposed in Congress.
We not here call for research on embryos. We do not call
for proscription of research on embryos. We simply say that where
research on embryos proceeds, it shall not proceed past a certain stage
I think that really is the gist of the recommendations.
Let me say in summary what I think are the major accomplishments, and
then I would invite members to offer their comments.
First, I think one of the great accomplishments of this
report is that this really is the first comprehensive survey of current
regulations in this area—what's going on, whose business is it to
do what, and how, what are the gaps in what it is we would like someone
to be paying attention to, what more do we need to know in order to
intelligently advance this conversation.
Second, we've placed a highlight on the well-being of the
women in these procedures, and especially on the children born with
their aid. And as the new technologies come to augment the existing
practices, the attention to these matters can only increase, and
it would be very important to try to beef up our—our monitoring
and oversight of their well-being now.
Third, we have been sensible and moderate with respect to
institutional reform. This is but a first step down that road. We
have not leapt in with both feet before thinking through carefully the
implications of doing something rather than nothing, and of doing this
something rather than something else.
We're not shying away from that further conversation,
but we are taking this slowly and carefully as we should. Regulation
has its costs, and they have to be assessed in the process.
Third, this is a very divided council on certain kinds of
questions. Once we get away from certain kinds of questions I have no
idea how divided we are going to be, and I'm very much looking
forward to the opportunity of moving into some areas where it's
going to be impossible to predict what the various members around the
table are going to say. And that starts in session two this morning.
However, I think it was a wonderful idea in this project to
say, "Look, let us search for common ground. We disagree about
much, but there's much more that we might agree about if we are
willing, in fact, to look for it."
And given the polarities and divisiveness in the nation, not only
on our questions but on lots of other questions, and given the fact
that this is a council that is Democrats and Republicans, liberals,
conservatives, pro-choice, pro-life, pro-research, scientists, humanists,
theologians, that we could show by example what could be done if
one, in fact, chooses to seek for common ground is I think a very
exciting development. And I suspect that that will get a lot of
People will snipe at us for not getting everything that they wanted
out of this, but I think fair-minded people will see, "Look
what these people have done when they, in fact, decided to look
for the values that they can mutually endorse rather than the ones
about which they disagree."
Next, although we have sought common ground and achieved
some kind of unanimity—and let me not exaggerate the unanimity,
because there are people here who are nervous about some things, and
not wrongly. If you tread in the area of legislation, even if we agree
as reasonable people that these things make sense, when they're
handed over to—to the legislative process, who knows who will jump on
this with what kinds of additional things, and that's a concern.
And it's been voiced by people here, and I share it.
Nevertheless, the agreement that we've reached here is not a compromise.
I want that to be stressed. These are principled agreements.
These are principled agreements on the recommendations in the tenth
chapter. Principled agreements—everybody is supporting these
for their own principles, but remarkably for different principles.
People are on board with these recommendations, not for the same
reasons but for very different reasons. And that's I think
also not surprising, but a very appropriate matter.
And the personal statements in this document—a great contribution—as were the personal statements in the cloning report, indicate
the multiple and different reasons why—that members of the Council
have for supporting these recommendations and for what it is that
they think the report doesn't do sufficiently or what it thinks
that it perhaps borders on too much.
But—so we have achieved unanimity not compromise, on principled
grounds, different principled grounds—we haven't, in order
to gain this unanimity, aimed at the lowest common denominator as
other attempts to gain consensus would have done. We haven't
done anything earthshaking here. This is modest, but this is a
modest but significant first step in an area where there have not
been first steps before.
No one has gotten everything that they want. We've all
gotten something I think that we care about.
Let me conclude by offering some kind of caveats, and this—these caveats are not addressed to members of the Council as much as
they are addressed really to the members of the public, given the
likelihood of misunderstanding because we are revisiting here,
especially in the recommendations, certain things that the Council has,
in fact, spoken about both in its cloning report and its monitoring
stem cell report.
Certain incomplete and, therefore, possibly misleading news stories
earlier this week written before the report's release—have
given some people the impression that the Council's unanimity
extends beyond what, in fact, it does extend to—namely, to the
still contested matters of embryonic stem cell research, federal
funding, and cloning for research.
This is not the case, and I think the public should
understand this. The personal statements in this report make it
perfectly clear that we still have deep divisions in this Council about
those matters, and that the conversation will continue.
What we've tried to do in this report, to repeat, is to
develop those concrete set of proposals that people on different sides
of the embryo question can accept for their own principled reasons, but
without foreclosing the crucial continuing argument which all of us I
hope will continue to make.
Second, concretely on the way in which this recommendation
relates to the cloning debate in Congress and how it relates to our own
previous cloning report, because I don't want this to be
When we moved again to recommend something that overlapped
with previous recommendations, I wanted it to be perfectly clear that
no one in this Council was going to be asked to repudiate a position
that they had taken previously, nor was the Council as a whole going to
repudiate its report on cloning. We didn't revisit that to debate
The proposal we are offering here is fundamentally
different, therefore, from the two cloning bans that are now before
Congress. One of them would ban the creation of cloned embryos for any
purpose whatsoever. The other will endorse research cloning and
prohibit the transfer of cloned embryos to initiate a pregnancy, thus
mandating that all cloned embryos be destroyed at some point in the
This recommendation does neither of these things. It
neither prohibits the creation of cloned embryos, nor does it endorse
the creation of cloned embryos for research. On this question our
report is silent.
It does not create a class of embryos that must be
destroyed. It does not prohibit the transfer of cloned embryos were
they do exist. It does not prohibit creating cloned embryos for
research. All it asks is that it creates—it prohibits the act of
creating a cloned embryo with the intent to initiate a pregnancy.
That's all we're saying on that subject.
In the Council's—this is a clarification and a way
forward on the Council's recommendation in the cloning report where
you will recall we unanimously called for a ban on cloning to produce
children, a report—a call we here clarify—to repeat and clarify.
On cloning for research, the majority then called for a
moratorium. The minority recommended that this practice should proceed
with recommendation. The Council has not, in this report, changed its
mind on that report.
Second and last, I don't think that there should be
misunderstanding about what the Council is saying in this report on
things touching embryo research and stem cell research. We have called
here for a moratorium on the buying and selling and patenting of human
embryos for any reason, and a moratorium on research that uses
latter-stage human embryos once they have reached a certain stage of
development. We have left it to the Congress to settle that between 10
or 14 days.
Regarding embryo research in earlier stages, and federal
funding of such research, those stages where embryonic stem cells are
derived, the nation and the Council, alas, are still divided. Some
members continue to believe that all embryo research should be
restricted or banned; other members believe that it should be
encouraged, accelerated, and federally funded much more than it now is.
What we agree on is only what we've got here—namely,
that research on embryos at a later stage is either wrong or imprudent,
at least for the time being, and should be placed under a moratorium.
In calling for this prohibition for the time being, the Council neither
endorses federal funding for embryo research nor opposes it, nor does
it propose limitations on research conducted with the very early stage
On those contested matters this report and this Council is
still silent. We are calling only for a restriction of the practice
that everyone believes should, for the time being, be restricted. I
think with these important clarifications, because there is a great
deal of danger of misunderstanding, lots of people on various sides
hoping to make use of this, I think we should simply say we've
agreed on certain things. I'm delighted that we have. I wish it
was possible to agree on more, but the society is divided on those
We will take a respite from those arguments here in the Council,
but that is where we stand.
I think that's both too much and too little, but that's
all I would like to say on behalf of the report as a whole, and
then placing my own particular emphasis on what I think are our
achievements, and try to correct some likely misunderstandings that
have already produced a flurry of phone calls to the office saying,
"You did what?"
So there it is, and the floor is open for discussion.
Before I ask for individual members who have asked to make comments,
are there any questions to me in terms of what I've just said?
Well, that's it.
Good. Well, I have a list of people who have asked to make
comments. And, Frank, since you are the founding father of this
venture, even if it hasn't produced quite the child yet in full
maturity that you had hoped for, perhaps you would be willing to lead
off. Frank Fukuyama.
PROFESSOR FUKUYAMA: All right. Thank you very much, Leon. I
am in fact extremely happy with the publication of the Reproduction
and Responsibility report. I want to thank the staff of the
Council for its assiduous, you know, pursuit of this issue. And I
think that the result, for all of the reasons that Leon just laid out,
is something that we can all be quite proud of. And let me also thank
the other members of the Council for working together to agree on it.
I think that since it's a relatively short statement
I'm simply—and since Professor Wilson has also signed on to this,
I will simply read the personal statement that I have written, because
I don't want to put words in Jim's mouth.
We believe that the Reproduction and Responsibility report
is a very important document that articulates a broad, moral
consensus over the limits that our society should place on new reproductive
procedures that are now made possible by technology. Proposed legislation,
if passed, would ban certain clearly unacceptable techniques, including
reproductive cloning, while at the same time neither prohibiting
nor condoning research cloning or other forms of embryo research.
As such, it shows a way to get past the current deadlock
that leaves the United States as one of the few developed countries
without guidelines in this area, and I think that's an important
point to stress.
Appropriate as these guidelines are, however, we believe
that they represent only a first step towards a more complete
regulatory approach needed to deal with these new technologies. Today
we can foresee possibilities like reproductive cloning or human-animal
hybrids that should be banned, but the technology will move quickly and
in the future pose ethical challenges as well as scientific and medical
opportunities that we have not today imagined.
It would be difficult and inappropriate for Congress to
intervene seriatim as these developments occur. What is called for
instead is a modernization of our existing regulatory structure to
allow it to respond with flexibility in such cases, taking into account
not simply the safety and efficacy of the new procedures but ethical
concerns that would be widely shared in our society.
Our hope is that the current report will represent not a
final word on the subject of the legislative limits but a beginning of
a broader discussion of regulatory oversight of new reproductive
technologies. As a general rule, we do not welcome government
intrusion into scientific inquiry and into the reproductive choices
made by parents.
But regulation frequently facilitates scientific advance
and individual choice by reassuring the public that it is being done
responsibly. That is the light in which the current report should be
seen as well as hope for future efforts to update and modernize our
Then, I would simply add in my own name. I have been
working independently through a study group to, you know, look at
further measures. I think at this point it is really not clear when
you talk about the modernization of a regulatory system what that
involves, whether you need actually new institutional powers, whether
the existing institutions can actually be modified in one way or
another to do that.
But I do think that we are at a juncture where we need to
consider this further. So I do hope that—that this, as I said in the
statement, will not be the last word on this subject. And I also would
like to, again, stress the point that regulation is not in this
instance an obstacle, I believe, to further scientific research.
I think that as in the case of biomedical technology more generally,
regulation is a—is something that actually promotes the possibility
of future research by making sure that people understand that it
is being, in fact, done safely and responsibly. And I hope that
people will take all of this in that light.
CHAIRMAN KASS: Michael Gazzaniga?
DR. GAZZANIGA: Well, there's going to be a certain
redundancy to these messages. And what I would like to offer here has
already been said as part of the record. It's not—it's my
earlier thoughts on this enterprise, and so there are no surprises here
that I have really never been happy with this effort since it was
launched. And the final report continues, really, to leave me
While drafts of this report have been freely available for
almost a year on the web, and while they have been updated and revised
as we all know, and we have certainly extensively discussed these
comments—all of this material at these meetings, I have never felt
comfortable with the thrust.
This is despite the fact that a few of us, in addition to
the time spent at these meetings, have spent many, many hours reading
it, suggesting changes to its language, and yet I get the sense of—I
was going to try some French here, but the more things change the more
they stay the same. But I never did well in French, so I won't
give you the translation.
Somehow this report starts out examining the regulatory
atmospheres of various reproductive technologies and concludes with a
set of recommendations that really have a newsworthiness. And, as Leon
has just pointed out, on this cloning issue the objective stated time
and again is to frame a set of recommendations that would break the
logjam in Congress on the issue of cloning.
This is achieved in the present document by suggesting we
outlaw any other means of making a baby except by the union of egg and
sperm, whether it be through normal sexual activities or through IVF
technologies. At this point in human history, this is certainly fine
The report also recommends any research use of leftover
embryos from IVF has to be completed by 14 days, and that, too, is
fine. What is not said, however, and as Leon has alluded, so this is
the redundancy here of the message and is left open, is whether or not
federal funding can be used to study those leftover embryos, or clumps
of cells as I would prefer to call them. They would serve as a rich
source, as we all know, for stem cell research.
It is also not stated that somatic cell nuclear transfer procedures—so crucial for therapeutic cloning—could go forward with federal
funding. Sometimes I think we have the sort of cloning version
here of the "Don't Ask, Don't Tell." I say again,
let's be explicit, and that's what my difference here is
I'm drawing—is I think we should move forward to being explicit
on these important issues.
And, finally, this Council has been through the issue
before—these issues before, as you all know. The one time we did
vote on anything in the Council, in 2002, the majority of us voted—10
to seven—to reject an outright ban on biomedical cloning. Ten of us
had no ethical objections in principle to biomedical cloning. Of that
majority, three major—three members wanted to, nonetheless, have a
moratorium until regulations were in place.
I now think we are moving towards having those recommendations
in place, and I hope and assume that these Councilors will soon
be ready to move forward and support federal funding of biomedical
CHAIRMAN KASS: Thank you very much, Mike.
I have Alfonso Gómez-Lobo next, please.
DR. GÓMEZ-LOBO: Thank you. Now,
the specific reasons I had to endorse the report are really
spelled out in the two additional statements to which I added
my signature, so I won't repeat those.
Now, what I'd like to do in this very brief statement
is, on the one hand, again call attention to the cultural and deep
background against which we are addressing these things, and then
I'll move to the specific recommendations.
In my view—and I feel very strongly that because of my
professional background I may be called to insist on this in this
Council—from my perspective, I view our culture as moving at a swift
pace towards the radical instrumentalization and exploitation of early
We're going by incremental steps, and early human life
I think is, of course, an expression that refers to human beings who
find themselves at a stage at which we all found ourselves at the
beginning of our own lives. We all started as a one-celled organism
and grew to be what we are today—namely, the same organism but with
millions of cells. And I am, of course, always willing to rediscuss
the question of identity through time.
But one of the consequences of that is that if we deserve
protection today, we deserved equal protection then. Of course, I
could expand this argument for hours.
However, in my view, going now to the recommendations, the document
we are unveiling today is a minimalist document. The recommendations
in the closing section of the report should be understood,
in my view, as minimal protections, as the least we should
It seems to me that the transfer of a human embryo into the body
of a member of a non-human species, the production of a human-animal
hybrid, if it works, the buying and selling of human embryos,
the patenting of whole human organisms, are all activities
that reasonable people should reject as basic violations of
our dignity. That is, as forms of instrumentalization. I
think that's basically what dignity means here.
The report also seeks minimally to restrict destructive or
harmful experimentation after a certain period in the life of an
embryo, because at present those legal restrictions simply do not
exist. We make no recommendation, however—and Leon has insisted on
this—on what should be permissible or impermissible during the first
few days of life, nor is there any recommendation with regard to
In fact, I join many Americans in thinking that destructive
or harmful experimentation on human embryos, either produced by cloning
or by union of the gametes, should be prohibited altogether. The
Dickey Amendment, of course, is I think, again, the minimal we could
If enacted, the recommendations of this report would raise
a very basic fence in front of activities that are, I think, deeply
dehumanizing, and I'm glad we could all agree on them.
CHAIRMAN KASS: Thank you very much.
Rebecca? Rebecca Dresser.
PROFESSOR DRESSER: This report responds to a significant
information gap. More information is needed on ART outcomes. Few
people would argue against the position that novel ART interventions
should be evaluated according to the criteria used to evaluate other
novel biomedical interventions, and that is safety and efficacy.
Yet a combination of circumstances has produced relatively
weak oversight for ART. Because the NIH and other federal agencies
rarely support research relevant to ART, innovative approaches may be
tried in patients without prior scientific or research ethics review.
Because novel ART procedures are ordinarily not subject to
the FDA approval process that governs drugs and other medical products,
ART procedures may be offered and performed without meeting the
agency's safety and efficacy standards. Because insurance coverage
for ART is limited, insurance company demands for properly qualified
practitioners and adequate facilities have less impact on the quality
of care than they do in other medical areas. And because causation,
negligence, and harm can be difficult to detect, much less to prove,
the tort system is ineffective in deterring substandard practice.
Now, the profession I think has made an important and
significant effort to assess its methods and encourage ethical practice
by clinicians, but more is needed. There is a professional medical
duty to make reasonable efforts to discover risks associated with
interventions that are offered to patients.
Fulfilling this duty is also in the profession's self-interest,
for careful evaluation of ART interventions will lessen clinicians'
exposure to liability for any alleged harm related to the interventions.
And there is also a broader social interest in learning
more about the effects of ART—for example, in learning more about the
possible health effects in children born after the use of these
interventions, and in learning more about the health of the women
undergoing superovulation, either as part of their own treatment or to
provide oocytes to others.
Now, if researchers are going to increasingly seek human oocytes
for research purposes, such as to create embryos through cloning
or IVF to serve as sources of embryonic stem cells, more women are
going to be exposed to these high doses of hormones and to other
parts of the oocyte retrieval procedure.
We really need to find out whether there are any long-term
consequences of oocyte retrieval. At minimum, we ought to have solid
information about risks to give to women who are thinking about
undergoing this procedure. And at a broader level, we should have this
information when decisions are made about whether the potential
knowledge gains generated through creating research embryos would
justify the harms it could produce.
Finally, the legislative recommendations the Council endorses in this
report are narrow and are designed to shift the burden to those
proposing certain questionable practices. These recommendations
seek to change the U.S. status quo from one in which individuals
seeking to engage in such practices have no obligation to explain
or give reasons for proceeding, to one in which such individuals
would be required to make their case—that is, to give reasons
that a substantial portion of the community would accept as justifications
for going forward.
This kind of a shift would place the United States with
many other developed nations engaged in ART and embryo research where
researchers and infertility specialists proposing novel investigations
or procedures must establish an appropriate basis for doing so.
Our constitution establishes a very general framework for
decisions about reproduction and research, but leaves most of the
issues discussed in this report to be resolved through the democratic
process. People dissatisfied with the present U.S. situation, whether
they are dissatisfied with the absence of constraints on embryo
research and ART practice in the private sector, or dissatisfied with
the absence of federal support for research involving embryos, or
dissatisfied with the lack of attention to potential social effects of
increased control over children born through ART—all of these people
face a choice.
Those who insist on securing every change they desire will
reduce the chance of securing any change. A more fruitful alternative
is to sit down with those who see things differently and to try to
craft policies reflecting points of agreement.
In developing this report, the Council chose the second
path. I hope those considering our recommendations will choose this
path as well.
CHAIRMAN KASS: Thank you, Rebecca.
PROFESSOR MEILAENDER: To gestate and give birth to this report
has been for us considerable labor. It is, I believe, a small
beginning at thinking about some very difficult topics, difficult
morally but also difficult in terms of the everyday life of many
Biotechnologies touching the beginnings of human life have,
for the most part, simply grown up around us. Not without thought, to
be sure, but largely without the kind of thought that gives direction
and sets limits.
It is not hard to praise their benefits, and it is not hard
to bemoan their effects on our understanding of parenthood and
childhood. But it is very hard to say what, if anything, we ought to
do or might be able to agree to do, given the circumstances in which we
now find ourselves.
This report at least gives us a developed context in which
to think about such questions. It makes clear our need for further
information, though I'm not confident that the information for
which we call will provide all we need to know, in particular
sufficient information about the condition of children born with the
aid of IVF or detailed information about the numbers of embryos
produced for our reproductive purposes but never brought to live
birth. So this is a very modest beginning.
The report does, however, move beyond calls for information
and conclude with some recommendations for interim legislation,
recommendations on which we have been able to reach consensus despite
our disagreements on a variety of related issues.
The problem with consensus, of course, is that it can often
be too cute by far, blurring rather than clarifying important
disagreements. And that will certainly be the case if we do not keep
faith with each other about the nature of the agreement we have
It may be useful, therefore, simply to note for the record
where these interim legislative recommendations leave us, what we have
said, and where we have been silent. With respect to cloned embryos,
the Council here says nothing that goes beyond or qualifies what we
said in our report "Human Cloning and Human Dignity."
Hence, the majority recommendation of that report, coupling together
a ban on cloning to produce children with a four-year moratorium
on cloning for biomedical research, has not been altered in any
way and remains our majority recommendation for legislation. We
have not uncoupled those two forms of cloning or recommended uncoupling
With respect to the use in research of so-called spare IVF
embryos, the Council has been able to agree only that there should be a
point in the life of an embryo at which such research should be
prohibited. We have not endorsed research prior to that point in an
We have certainly not recommended government support for
research on human embryos at any point in their life, nor do our
recommendations in any way suggest that the current prohibition on
federal funding of all research that destroys embryos should be
We have not recommended a prohibition upon the implantation
of any embryo, and we have not said anything at all about what should
be done with embryos at the point where research must stop.
In the context of all those silences, we have said only
this: recognizing that there is research not governed by the
restrictions on federally funded research, we have simply recommended
that if anyone carries out research on living human embryos there be a
point at which such research must stop.
Thus, the silences surrounding our agreements are very
large and complex. And lest good faith be replaced by duplicity and
mistrust, I hope their complexity and their largeness will be both
appreciated and honored by all of us.
CHAIRMAN KASS: Thank you.
PROFESSOR SANDEL: Thank you. Much of this report
concerns fertility clinics. But as the comments around the table
have already made clear, the two elephants in the living room are
cloning and stem cell research. A great merit of the regulations
in the report is that they point to a possible solution to the vexed
issues of cloning and stem cell research that could overcome the
current impasse in the United States Senate.
First on cloning. Despite the widespread opposition to reproductive
cloning, the Senate hasn't been able to ban it because of disagreement
about cloning for biomedical research. This report offers an ingenious
way of detaching those two questions. It proposes that Congress
prohibit attempts to conceive a child by any means other than the
union of egg and sperm.
This language provides a way for Congress to ban
reproductive cloning while agreeing to disagree on the question of
cloning for biomedical research. Congress could prohibit attempts to
create cloned children while allowing debate to continue about cloning
for stem cell research and regenerative medicine.
The proposed regulations taken together also point toward a possible
compromise on federal funding of stem cell research. They do so
by addressing at least one of the main worries people have about
stem cell research, which is the slippery slope worry. This is
the worry that without clear limits, embryo research could lead
down a slippery slope of exploitation and abuse.
If we allow stem cells—stem cell research today, the
argument goes, tomorrow some people might try to transfer embryos into
a woman's uterus, or even a pig's uterus as we've heard
said, to grow organs for transplant, creating the nightmare prospect of
embryo farms, fetuses exploited for spare parts, and the
commercialization of human life.
The regulations contained in this report address that
slippery slope argument. They do so by assuring that such research is
done responsibly, within carefully prescribed limits. No embryos used
for research could be used or preserved beyond a 10- or 14-day limit,
or transferred into a woman's uterus or into an animal's body
to grow organs for harvest, nor could embryos be bought and sold.
By assuring that stem cell research is conducted within
these limits, these regulations address the slippery slope objection,
the worry about exploitation and abuse. And so they point the way, or
so it seems to me, toward a compromise on federal funding along the
lines that were proposed back in July of 2001 by Senator Bill Frist.
Senator Frist argued then that both embryonic and adult
stem cell research should be federally funded, but within a carefully
regulated framework, and these regulations begin at least to create
such a framework.
Now, why is this important? Well, recent scientific
developments illustrate the need to adjust federal funding policy along
the lines that Senator Frist proposed. Only 17 cell lines are
currently available on the NIH registry for federally funded research.
Just a few weeks ago, Harvard Biologist Douglas Melton announced the
creation of 17 new embryonic stem cell lines that he is making available
free of charge to scientists for non-commercial research purposes.
The Harvard stem cell lines meet all of the criteria proposed by
They were derived using private funds from blastocysts left
over from IVF clinics, not from— nothing involved with cloning—blastocysts left over that would otherwise be discarded and with the
consent of the donors. They meet all of the requirements.
And yet, under current federal policy, research on these cell
lines is ineligible for federal funding. Despite meeting all other
ethical and legal requirements, these new cell lines were derived
after 9:00 p.m. on August 9, 2001. That's the only difference
between them and the approved lines.
Now, the August 9th cutoff may have been a reasonable
compromise two and a half years ago when it was thought that some 60 or
70 cell lines would be available. But in the light of what we know
now, that August 9th cutoff looks less and less sustainable, both
practically and ethically, because whatever one's view of the moral
status of the embryo it is difficult to understand the moral
distinction between research on stem cell lines created before 9:00
p.m. on August 9, 2001, and research on stem cell lines created
according to all of the same ethical requirements except for the fact
that they were created later.
And so I endorse the regulations proposed in this report in
the hope that they can point the way to a national compromise on both
cloning and on federal funding of stem cell research—a compromise
that will enable this country to promote the promise of stem cell
research while upholding the highest ethical standards.
CHAIRMAN KASS: Thank you, Michael.
I have just two more people, so that people know where
we're going. I have Robbie George and Dan Foster.
PROFESSOR GEORGE: Thank you. I wish to begin by associating
myself with the careful exposition of the content of our report this
morning that was provided by Dr. Kass. And also, I wish to thank him
for the careful clarifications which I hope will help to prevent
misunderstanding of the report, some of which is already abroad.
I'd like to direct my comments this morning not so much
to my friends and colleagues on the Council, but broadly to citizens
who are following our deliberations, and particularly to those citizens
who share my own basic perspective on the fundamental ethical questions
having to do with embryo research.
So I ask: how ought the targeted measures proposed in
Chapter 10 of the report we released today be regarded by members of
Congress and by citizens who share the belief that human beings in
every stage and condition, including the fetal and embryonic stages,
are entitled as a matter of strict justice to full respect and legal
I hope that they will be regarded as, in Dr. Kass' apt
words, significant, yet modest, steps forward. Of course they will be
regarded, and in my opinion should be regarded, as not enough, for even
if all of our recommendations were enacted into law injustices would
remain in my view.
The moral ideal and the ultimate political goal must be
full legal protection for all living members of the species homo
sapiens, all human beings, irrespective of age or size or stage of
development or condition of dependency or location. It should never be
lawful to treat a human being as a mere property or as disposable
research material or as a collection of cells or tissues or organs to
be harvested for the benefit of others.
As Professor Gómez-Lobo and I say in our statement attached to
today's report, biomedical science should move forward aggressively
by all ethically legitimate means in its mission of curing diseases
and ameliorating suffering, but also adding to the sum of human
knowledge. Respect for human dignity requires nothing less than
But the very same principle of respect for human dignity
also requires strict adherence to ethical norms protecting the moral
equality and inviolability of each human being. It is my hope that our
law and public policy will move steadily in the direction of full
respect for human dignity and protection for human life in all stages
The targeted measures proposed in Chapter 10 should be supported,
I believe, because they move us in the right direction. They do
not weaken or diminish any protection of nascent human life currently
in place. They do not alter the prohibition, for example, of federal
funding for destructive embryo experimentation and research.
Their sole legal effect would be the desirable one of
restricting unethical practices which are currently unrestricted by
federal law, including some that are unfortunately encouraged by some
Today's recommendations are being proposed unanimously
by our Council. Although for some of us they are worthy of support as
important steps in the right direction, for others they represent all
or most of what should be done by way of restricting research involving
the destruction of nascent human life. As Chairman Kass has indicated,
we remain divided on these basic moral questions.
We remain divided as a Council on the question whether all
embryo destructive research should be forbidden. We remain divided on
whether cloning to create embryos for research should be permitted or
proscribed. Today's report leaves unaltered our recommendation on
that issue contained in the Council's report entitled "Human
Cloning and Human Dignity."
But these continuing divisions should not obscure the
considerable consensus we have reached. Even members favoring embryo
research agree that even privately funded research should be subject to
significant federal restrictions.
Even those who support research involving the destruction
of human embryos in the blastocyst stage agree that after a certain
point in development—10 to 14 days or fewer—the use of embryos for
research involving their destruction should be banned.
Moreover, in an important preemptive strike against the emergence
of fetus farming for transplantable tissues and organs, the Council
is united in recommending a ban on transferring a human embryo into
the body of a member of a non-human species for any purpose or into
a woman's uterus for any purpose other than attempting to produce
a live-born child.
I know that many of my fellow citizens of New Jersey,
alarmed by legislative developments in our state, will applaud the
President's Council on Bioethics for its moral leadership in making
these particular recommendations. On the other hand, it is already
clear that two of our recommendations are being received with caution
and concern by citizens who believe in the full dignity of human beings
at every stage of development, including the embryonic stage.
The first of these is the proposed day limit on privately funded
embryo destructive research. Some people fear that this will be
perceived as an authorization of embryo destructive research prior
to the limit.
I would respectfully ask those who share this view, this
concern, to consider the points advanced by Professor Gómez-Lobo and
myself in our statement attached to today's report, as well as
those developed in the statement in which we are joined by Professors
Meilaender, Glendon, and Hurlbut.
The second point of concern has to do with the operational
definition of the proposed ban on attempts to conceive a child by any
means other than the union of sperm and egg. On this point, the
Council has attempted to find a way to preempt development of
industries that would produce children who would be deprived of the
rights and human attachments naturally available to children conceived
A substantial body of opinion on the Council, and which I
share, believes that the right way to proceed here is to ban the
creation of such embryos by certain processes.
For now, however, this does not appear to be feasible
politically. So our goal has been to design an approach that would
provide an effective deterrent in the face of disagreement to the
development of an unethical industry while at the same time avoiding
any suggestion of legally mandated embryo destruction or placing limits
on bona fide embryo rescue.
It's also important to note that we leave untouched the Council's
recommendation of a four-year moratorium on the production of embryos
by cloning for biomedical research, during which time those of us
favoring a permanent and complete ban on human cloning would continue
vigorously to make the case for such a ban to state and federal
legislators and to our fellow citizens.
Whether our proposal on this particular point is a prudent
way to proceed is a legitimate question that should be reflected on and
carefully discussed by people who share the goal of protecting human
life in all stages and conditions. People who share the foundational
ethical conviction may differ in the matter of prudential judgment, yet
careful thought and discussion may yet yield consensus.
So to those who have concerns on this point, I would
respectfully say that we should embrace those recommendations made by
the Council today, which all of us can see advance the goal of respect
for the life and dignity of the human person, while resolving to work
together in carefully thinking through the matters on which differences
of prudential judgment persist.
CHAIRMAN KASS: Thank you very much.
Dan Foster, last but by no means least.
DR. FOSTER: Well, you'd better not say that yet.
So anyway, I want to make a real-world comment, sort of in response
to Leon's earlier explanations, and not comment on the report
itself. I thought the statements were very good.
One of the characteristics of the Council in its first two
years has been open discussion, so that there has always been a
transparency to the thoughts of the members, and that was one of its—has been one of its great strengths. And in that spirit, I want to
acknowledge a transparent fact briefly and without polemic.
And that fact is this: that the reconstitution of the
Council has evoked strong concern externally, especially amongst the
scientific community. The concern is that the Council has become
unbalanced. Two strong members of those who hold science to be a high
good have left and have not been replaced.
Consequent to that, some members of the Council itself have been concerned
and have conveyed that to Leon—this issue of the perceived imbalance
that I have mentioned. And I thought it would just be crazy to
have a meeting here and not acknowledge that rea-world fact.
My colleagues would say, "What is this with all of
this going on that there's no comment about the
reconstitution?" And that's the purpose of my statement here.
I want to point out that the concerned Council members are
all here. And, further, I think it fair to say that they think that
the Council has been a good thing, and has done good work, despite the
Now, three quick comments, and I'm through, about how
to deal with this. First, the Chairman has always been fair in letting
issues be amply discussed in meetings. He frowns a lot, but he has
allowed ample discussion to take place.
Second—and this is to many of our scientific colleagues
who felt that those—that we should not stay on the Council. I can
tell you that there are many, many of the major scientists in the
United States who felt that the reconstitution was such that we should
But my view is that it's almost certainly better to
have the voice for science present in future discussions than absent,
even though we're smaller in number. And that's because
science and scientific medicine is a very high good, and most of the
people in this country know that. So it's good, I think, to those
who say "leave" that we stay.
And, third, there is always the possibility that
rationality will conquer and that Leon and the older members on the
"other side" will change their view. And I certainly assume
that as we welcome the new members to the Council we will do everything
we can to make them become more rational, too.
CHAIRMAN KASS: Charles?
DR. KRAUTHAMMER: I just wanted to make a—I have no
statement to make about the report, but I have been provoked by Daniel,
as I have been in the past many times.
DR. FOSTER: Charles, I've been provoking you ever
since I joined this Council.
DR. KRAUTHAMMER: Well, it finally worked.
I respect what you say, and I understand the sincerity and depth
from which it comes. But you talked about perceived imbalance.
We've heard about that perceived imbalance for two years now,
including the Council as composed in the past, which we are now
idealizing, and which when the Council began two years ago was characterized
in the press and elsewhere as analogous to the Taliban, among others.
So let's remember where we started from.
I think anybody either reading this report, anybody hearing
our discussion this morning, would say that the idea of perceived
imbalance is only a perception. We have just heard from Michael
Gazzaniga a reference to the embryo as a clump of cells. We have heard
it referred to by Robbie George as the—deserving the dignity afforded
a full human being.
We have the full range of philosophical approaches on this
Commission, and I think it reflects very much the divisions and
disagreements in society itself. I believe this Council is the most
diverse, open, and reflective of any bioethics council ever constituted
in this country.
And I think the fact that we produced a report today where
we achieved unanimity despite our differences is a tribute, a) to the
sincerity and the willingness of us to work together on common goals,
and b) to the fact that in a diverse society we can actually have
ultimate agreement on basic goods.
So I understand how there is a perception about a lack of
diversity, but I don't think anybody with a fair mind, hearing what
we have heard today, reading our report, could conclude anything except
CHAIRMAN KASS: Thank you very much.
Thanks to all Council members. And, Dan, let me single you
out. Thank you very much for that comment. I think it is good that
the concern of the larger community is acknowledged here, and we will
continue to strive in every way possible to make sure that every
respectable opinion is heard, welcomed, and given the full weight that
And on the question of being able to listen to reason, the
conversation is always open, and persuasion is the ultimate
possibility, and we look forward as we move forward to new topics to
learn from one another and try to reach greater clarity, either about
what we can't agree on, but certainly to try to find common ground
as we proceed.
We have run over. I'm long-winded. Council members are wonderfully
articulate. Let me say the following. We want to have at least—without stealing too much time for the next session—we have
a couple of people—we have five sort of personal statements, four
There are two who have asked to speak, people who have worked
very closely with us in preparing this report. Pam Madsen
from the American Infertility Association, the Executive Director
there, and Erin Kramer, who is the Director of Government
Affairs from Resolve, would like to offer a comment at this
Then, we're going to have to take at least a few
questions from the press for maybe five minutes. The rest of them we
can deal with at the break. But let's at least have these
comments. I will call attention to the other press releases that we
have, so that people can read them, and I won't take up valuable
Ms. Madsen, would you please come forward? And welcome back to
our gathering. It's nice to see you.
MS. MADSEN: I do have a prepared statement that is out
front, but I've actually chosen not to read from it, because if you
want to read that you can read it.
First of all, I stand before you as probably one of the
most recognizable faces and voices of the infertile community, as I
have been doing this work for 15 years, and I was an infertile person.
I'm now a mother of ART children.
I want to first begin and thank you all for listening,
listening to the stakeholders that have come to you. I want to thank
you for responding to us, because the responses—and, yes, there
obviously has been division, and there has been division even when
I've been thanking you. I've been told maybe I shouldn't
thank you. So division has always been quite present. But your staff
and your chairman and all of you have worked very, very hard to be
attentive and responsive listeners.
And on behalf of the community that I represent, I do think
we feel responded to. Many things that we were extremely unhappy with
are no longer in the report, and we thank you for that. There are
wonderful things as well that we support, that we do think is going to
help the patient community—the women, the husbands. You know, we
don't talk about the husbands around this table. It's always
about the woman.
But there's actually usually two people who go in for
treatment. It's the man and the woman, and then there's the
resulting children. So for the protections for the couple and our
children, we support any help that you can give us to get funding for
prospective, balanced studies for the health and welfare of our kids.
And nobody cares more about that than patient organizations, because we
are the mothers and the fathers of our children.
As many of you know, the American Infertility Association, in
partnership with Randt, is working to get funding for Footprints,
which will be the first prospective IVF study in children in this
country. And it will be run by stakeholders, not by people with
political agendas. All we care about is an honest outcome, because
we care about our kids.
We care about you supporting funding to help the women who
are taking known and unknown risks for the dream of a child. We want
to know what we will face later in life, and very well nothing. Maybe
something. But do we really know? No, we don't. So thank you for
We thank you for preserving the rights of the individual to pursue
collaborative reproduction without government interference. We
thank you for listening to us. We thank you—I have to acknowledge
Carter Snead, who has been a great ear to bring things to the Council
for us. We said, "How come you're not talking about insurance?"
And in this final report we see mention of the importance of insurance.
And we agree with your recommendation for publicly reported
data to include the cost of ARTs to patients, as well as a number of
ART patients, in addition to the number of cycles. We feel that this
is very critical information that all patients should have.
Do we have some issues with the report? Everybody has
issues. Everybody comes to the table with different viewpoints. And,
yes, we too have some issues and anxieties, as Dr. Kass mentioned I
think in the very beginning.
We have some issues with what we consider ambiguous
language in some of the recommendations, such as the union of egg and
sperm and creating a child. Well, does that mean we can't do
ooplasm transfer or cytoplasm transfer? What does that mean?
I've been assured by the Council that it doesn't mean
that, but this is a political document. It's going to travel
up. Are you going to be there to explain exactly what it means
to members of Congress? I think you need—this is a pre-publication
report. There's a possibility for clarity of language. It
would help everybody interpreting your report to have a bit more
clarity around some of these recommendations.
Thank you for inviting me repeatedly. Thank you for
listening. Thank you for responding. And I bet that you will respond
CHAIRMAN KASS: Thank you very much, Ms. Madson.
Erin Kramer, please. Welcome back.
MS. KRAMER: Thank you so much. We also at Resolve, the
National Infertility Association, would very much like to acknowledge
the time and effort of the Council members, the chairman, who has spent
a great deal of time trying to be responsive to the various occasions
when we've expressed concern about elements of earlier drafts, as
well as the staff.
We think that there has been a great effort in at least
being responsive and trying to be clear about what is the Council's
intent in different versions. And we want to acknowledge that you
responded to our concerns about what we originally have thought were
very overly burdensome proposed regulations of pro-pregnancy
treatments. Again, that's what we're talking about here is pro-pregnancy treatments for these couples.
We do, however, remain concerned about some aspects of the
final report. You know, the stated intent is consumer protections.
Yes, we know that. But we feel that it may also make these medical
treatments for the infertility of infertile couples more costly and
less successful. We think that's going to be the reality.
And we are wary of proposed governmental monitoring and
publication of all aspects of fertility treatments to a degree that we
still think is unheard of in other areas of medicine.
Our challenge, of course, is the next steps. Our challenge
is seeing this as it moves forward. And we are going to make sure that
if and when these recommendations are acted upon, they are implemented
in a manner that is fair, is unambiguous, and is in the best interest
of the millions of U.S. patients and their children.
We are going to remain vigilant to ensure that any further
application of these recommendations does not limit access to medically
necessary infertility treatments, does not unduly restrict the privacy
of the people working so hard to build their families, and also the
privacy of their reproductive choices.
We do applaud the Council for removing earlier
recommendations and language that we thought was very hostile to ART,
and that we thought in the end would be damaging to those seeking
medical assistance to build their family.
And we also recognize the Council for pointing out the
important need for federal funding for the studies of assisted
recommendation and also for including language in the final document
that speaks to the issue of insurance, although we still feel that we
will continue in our efforts for what we do think is the most important
consumer protection, and that is procuring insurance coverage for those
individuals working to build their family.
CHAIRMAN KASS: Thank you very much.
Let me make an administrative decision. We have a
distinguished guest who is—we have already held—we have run 15
minutes over our time. There are—I would be remiss if I didn't
simply mention that we have a press release from the American Society
of Reproductive Medicine and the Society for Assisted Reproductive
Technologies. They have released a statement. This statement is
available on the press table.
I was going to read it, but I will not do so. They've
been wonderful to work with, and we've learned a lot from them, and
we will continue to work with them as we will with the patient groups.
We have a joint statement from the group Our Bodies
Ourselves jointly issued with the Center for Genetics in Society, Judy
Norsigian—and I've just lost page 2—and Marcy Darnovsky. This
statement is out there, and they are willing to be called about this
And we have a statement from John Kilner from the Center
for—President for the Center of Bioethics and Human Dignity,
and a statement from Lori Andrews who has been one of our
consultants. I will not read these. These are available
to people who would like them.
In the interest of not spoiling the rest of the day, let me
simply say I will stay here through the break and be available for
questions from the press. Members of the media may also, of course,
speak to other members of the Council.
Let us take a break, and let us reconvene here at a quarter
of 11:00, so we can hear Dr. Jessell's presentation.
Apologies to those members of the press who wanted the
microphone, but I think we can try to help you get your stories written
if you speak to us individually. And I'll simply stay here.
This session is adjourned. We'll convene in 12
(Whereupon, the proceedings in
the foregoing matter went off the record at 10:33 a.m. and
went back on the record at 10:52 a.m.)
SESSION 2: NEUROSCIENCE,
BRAIN, AND BEHAVIOR I: BRAIN DEVELOPMENT IN CHILDREN
CHAIRMAN KASS: Session 2 of our meeting, Neuroscience,
Brain, and Behavior I: Brain Development in Children. From
reproduction and the beginning of bodily life to the brain and the
functions and flourishing of mental and emotional life. Everyone
senses the great excitement of neuroscience and modern psychology,
methodical investigations by the mind of the mind to increase the human
understanding of the human, prospects for addressing mental illness and
aberrant behavior, and improving our abilities to make the most of our
native mental capacities. Everyone also vaguely senses that those
exciting new discoveries might be accompanied by new ethical, social,
and philosophical challenges precisely because these studies touch so
directly on many of the powers and activities that make us who we are:
awareness, memory, imagination, desire, motivation, thought, feeling,
and moral judgment itself.
The Council is interested in learning about the developments in
neuroscience and psychology present and projected that might raise
significant ethical and social issues either because of the technological
interventions to which they might lead, or because of changes in
human self-understanding that they might invite. In our Beyond
Therapy report, we explored some of the psychotropic drugs that
alter behavior, memory, and mood, in the service of goals beyond
therapy. But we sense that this was just one of a number of challenging
issues that might emerge from this field. At the last meeting we
got a beginning in this area with introductory presentations from
Robert Michaels on neuropsychiatry, by Jonathan Cohen on brain imaging
and reward and decision, and you'll recall that we decided at
that meeting before proceeding further to find out which aspects
of this large domain were most worthy of our attention, that we
should try to learn something about just the foundations, about
normal brain and mental development, especially in children. So
today and the rest of today is about those foundations, the scientific
foundations of normal brain and mental development in infants and
The questions behind these discussions are really these.
What can neuroscience and developmental psychology tell us, either now
or soon, that might be relevant for understanding how best to raise
flourishing children and adults? What can neuroscience and
developmental psychology tell us that might be relevant for
understanding and preventing disordered or dysfunctional children or
adults? But the explicit discussion, as opposed to these larger
questions, the explicit discussion will be the science itself,
neuroscience in the morning, psychology in the afternoon, and at the
end of the day we'll have a chance to take stock of what we have
done and how far we have come.
It's my great pleasure to welcome Dr. Thomas Jessell
who is Professor of Biochemistry and Molecular Biophysics, the Center
for Neurobiology and Behavior, and Howard Hughes Investigator, at
Columbia University. He is a distinguished researcher in the field of
brain development. It's a great pleasure to welcome you to the
Council. Apologies for detaining you, and we very much look forward to
your presentation. Dr. Jessell has asked me to announce that he would
very much welcome our interruptions if we have questions or things on
clarity. He wants to make sure that we're following. Dr. Jessell,
the floor is yours, and thank you again.
DOCTOR JESSELL: Well, first I would like to thank Dr. Kass
for this opportunity to participate in this discussion of brain science
and its relation to behavior. And just to echo these comments that I
really would encourage interruptions, comment, dissent, clarification.
If I lapse into jargon, then please bring me back to clarity.
Perhaps in the light of the first session this morning, an
interesting place to start this discussion is in fact early in
embryonic development, because it's at a relatively early stage in
development that nervous systems form, that nerve cells are generated,
and that those nerve cells begin to acquire identities that drive the
subsequent formation of connections within the developing brain. And
one of the things that I'd like to suggest or argue in my comments
this morning is that to a large extent the precision with which those
connections form governs the intrinsic behavior or repertoire of any
organism, whether it be a child, any type of mammalian organism, even
lowly invertebrates. Behavior is in large part dependent on the nature
of the circuits that exist within those nervous systems.
Now that is not to say that the wiring diagram, if you
like, of the nervous system is the only determinant of behavior. I
think we've understood for many years that this provides an
architectural substrate upon which environment and experience then mold
those connections and refine those connections to produce the full,
rich repertoire of behaviors that any given organism is characterized
So one of the things I'd like to discuss this morning
initially at a relatively reductionist level is really to review what
the field in general has learned about the nature of brain development
during embryogenesis and postnatal development. What is the
relationship between genes, neurons, circuits, and behavior? What are
the molecular determinants that begin to establish the structure of the
nervous system? Then discuss the interplay between these genetic
programs and environmental influences. When does the nervous system
cease to develop, if you like. When is the pattern of connections
established in a way that cannot be changed? And our views on that
have also changed rather dramatically over the last 10 to 20 years. So
we're dealing with questions of plasticity of the nervous system in
relation to circuits and the way that those circuits influence
behavior. So these are all normal developmental processes, if you
like, and perhaps if we have time at the end I will turn to the way in
which those normal developmental processes become subverted in brain
disease, in various types of neurological and psychological,
psychiatric disorders. Now those are very large problems, so I think
at best I will be really scratching the surface on some of those later
So just to put things into a general context. Now, I hope that
everybody can see some of these images, because some of my
comments will really be dependent on them. And those on my
left are in danger of being attacked by this laser pointer,
but I think we're working at the moment. So what you
are looking here is in very superficial terms the process
of human brain development as a function of the nine months
of gestation. And so somewhere within the third to fourth
week, the nervous system begins to form. So cells in one
of the major germ layers of the embryo, the ectoderm, make
a decision that they're going to acquire neural character
as opposed, for example, to acquiring the properties that
eventually give rise to skin. So the first steps in the formation
of the nervous system occur at a surprising early stage.
And then as you can see because this is drawn relatively to
scale, what happens over the subsequent eight months of embryonic
development is a process by which the nervous system at least
in large part accumulates large numbers of cells. So the
nervous system is exceedingly small at these early stages,
but as you can see, by the time an embryo is born at nine
months of gestation, there is a very highly organized nervous
system which is much, much larger than the anlage that was
seen at three to four days. And so what we're really
looking at at this period, and this process continues, not
just in embryonic life, but in postnatal development. Neurons
continue to be added.
So in a sense what the field of developmental neuroscience
at these early stages has been trying to address are two basic
questions. So one of these relates to numerology. So these are
estimates, but the human brain is thought to contain some
1011 neurons. This is a staggeringly large number of
neurons. And it also contains, and again this is simply an estimate,
at least 1,000 different classes of nerve cells. So by comparison,
with most other tissues and organs in the body, the extent of cell
diversity inherent in the nervous system is observed at a much more
extreme level than in the liver, or in the heart, or in other tissues.
And so one of the major questions is to understand how during
development the nervous system controls the number of nerve cells that
And the other thing that this image shows is that not all nerve
cells, once they're produced, are the same. Individual nerve
cells have discrete functional properties, and some of those functional
properties are inherent or derived from the fact that the morphology,
the shape, the structure of those nerve cells is markedly different.
So on the right-hand side of the screen here we're looking at
one nerve cell that is found in a part of the brain called the cerebellum
that is involved in motor control and many other functions. And
you can see that that cell, that neuron, looks very different from
a neuron found in the retina that is involved in visual processing.
So one of the things that development does is ensure that not only
do you generate very large numbers of neurons within the developing
human brain, but you make these neurons different from a very early
stage in fundamental structural ways that presumably influence their
later functional properties.
And I'll talk a little bit about what we currently understand
about how these two problems of generating neurons and making
neurons different are achieved at a developmental level.
Now these neurons don't exist in isolation. The functional
property of the neuron is dependent on that neuron becoming
incorporated into a functional neural circuit, a network of
neurons interconnected in different regions of the brain such
that the combined activities of many neurons in different
parts is necessary to produce a given behavior.
So the problem becomes even more complicated at this
point. So if we look at a typical region, for example the cerebral
cortex, what we're seeing here is a complex, dense mesh work of
neurons. And this has been appreciated from classical anatomical
techniques for the last century or more. So each of these individual
neurons as you can see from their morphology is subtly different from
their neighbors. One of the questions is how do these differences in
morphology, these differences in structure, relate to the types of
connections that they produce.
So the two general questions that I want to begin to
address, at least in the first part of my comments, are really going to
be the issue of the impact of genes and genomes on neurons, on neuronal
identity, and the way that those neurons begin to assemble
interfunctional circuits. So if you like, this is a reductionist view
in which many aspects of brain organization are achieved through a
genetic program to result in a wiring diagram of the brain.
So how are neurons generated? This is perhaps the
fundamental problem, the event that has to proceed if all other aspects
of circuitry and behavior are going to be achieved. And this is a
problem that has been appreciated for, again, almost a century. But
it's only very recently that we have any molecular understanding of
the way in which a cell in a primitive ectoderm acquires a neuronal
property. And this is a process that is reiterated many, many times to
produce this vast diversity of neurons that exists in the human brain.
And so if we look from classical studies by Pasko Rakic and others,
what we're looking at here is a small region of the developing
brain, in this case a region of cortex. And so in this region what
you can see is a layered, a striated structure here. One particular
region called the ventricular zone, which you can't really see
properly here, is the site of the precursors that will give rise
to nerve cells. These are neuro-precursors if you like. They're
stem cells in a particular context of neural development. So these
cells lie at one side of this epithelium, this sheet of neural cells.
And those cells divide under tightly controlled programs. And the
process of division here will determine whether that precursor cell
continues to remain a precursor cell with a capacity to divide further,
or whether that cell will leave the cell cycle and acquire so-called
post-mitotic neuronal property. One of the characteristic features
of neurons is that once they're generated, they never undergo
further divisions. So this is a crucial event in determining the
number of cells that populate the nervous system to determine how
many of the precursor cell population remain, and how many post-mitotic
non-dividing neurons are produced.
And the classical view until a few years ago had been that
these cells divide in this restricted germinal or ventricular zone, and
then they migrate through a complex process series of cellular events
away from this germinal zone into their eventual settling positions in
other regions of the nervous system. And one of the ways that
they're thought to undergo this migration process is along a
series, if you like, of tram lines, or structural elements called
radial glial cells which act as conduits for this migration process.
So really there are two processes going on here at these very early
stages. The process of cell proliferation coupled with the decision to
give rise to a neuron, and then the migration of the neuron along these
Until very recently, and part of the reason I'm
mentioning this, is to indicate that some of our thinking on these
processes, even though the problem has been identified in classical
terms. Some of our thinking and some of the information is really
very, very recent. So much of what I'm saying is really a current
2004 view of these processes. But this is still a field that is in a
state of considerable flux.
So the classical view, which is shown on the left-hand image here,
is that neurons achieve their final position within the nervous
system through this migration. They ensheath, they intertwine around
these radial glial cells, and that's the way they move. But
the radial glial cell and the neuron have been thought of distinct
cell types with no relationship. What we now know from work in
the last five years or so from many people is that this is certainly
true, but this is an oversimplification, because it turns out that
the radial glial cells, these structural elements, not only serve
as a scaffold for neuronal migration, but they also represent in
many ways the precursors of neurons themselves. So the radial glial
cells have a dual role. They not only generate neurons, but they
then act as a scaffold. And I'll just give you one example
of this new view. So here we're looking almost in real time
at one of these radial glial cells. You can see its processes spanning
the length of the future cortex. And if we follow that cell in
real time, although I'm showing it in a series of static images,
what you can see is this cell divides at around Time Zero. And
then there are two cells. And as we follow with time, one of the
progeny remains in the ventricular zone, presumably to remain a
precursor cell, but the other cell begins to migrate along this
structural element. And by using various genetic markers, some
of which are not showing actually on this slide here, what we can
see—there's a slight technical problem here, because this
cell would be labeled Red with a neuronal molecular marker. So
this type of real-time imaging here is showing that radial glial
cells are in fact the precursors of neurons. So this is a piece
of cell biology that has emerged over the last few years that has
radically changed the way that we think about neuronal production
in the developing brain.
So can we move then from this cellular description of where neurons
throughout the central nervous system, throughout the brain, come
from, into a molecular understanding of this decision. What are
the genes that determine whether a cell remains proliferative, or
whether it exits the cell cycle and acquires a neuronal fate And
over the last decade there have really been very substantial advances
in understanding the nature of genes that drive this neuronal differentiation
process. And one can show that some of these genes are sufficient
when expressed in a proliferative cell to produce the neuronal phenotype,
to produce the neuronal fate. And I'm showing you one example
of this. The nature of the genes don't really matter here.
But what we're looking at is a top-down view of an early vertebrate
embryo. And so this has a left side and a right side. And on the
left side, if we concentrate on, for example, the image in Panel
B, you can see a few blue dots here. Those are the neurons that
have been generated under a normal developmental condition. And
you can see that there's a sea of non-neuronal tissue in which
are interspersed individual nerve cells. So in this experimental
situation, a single gene that is one of these genes that promotes
neuronal formation, has been introduced into these precursor cells,
and the consequences for neuronal production have been examined.
And what I hope you can see is that to the right of this dotted
line there is a vastly greater number of nerve cells that have been
generated as a consequence of introducing that one gene. So neuroscientists
now are beginning to be able to control this early decision as to
whether to give rise to a proliferative cell or whether to generate
a nerve cell. And these are genes that are operating in the embryo
normally, and this is part of a genetic program that in a sense
is determining the fact that the human brain has 1011,
not 1012, not 1010 neurons. So there's
a tightly orchestrated genetic program that ensures the production
This image indicates, at least with this sort of color-coding,
that all neurons are the same. So there are really two problems
here. One, as we saw, to generate large numbers of neurons. But
the second is to make those neurons different. And so if we consider
that the human brain at the time of birth contains some 1,000 different
cell types, how are those different cell identities? They're
all neurons, but each of them acquires a characteristic identity
that suits its particular later function. How is that diversity
of neuronal identity controlled? So if there are 1,000 different
classes of neurons, does that imply that there must be 1,000 different
signaling mechanisms that are operating with one pathway of signal,
one signal per neuron, which would provide extreme constraints on
the number of genes necessary to generate this diversity. Or has
the nervous system evolved more efficient ways of generating diversity
from a relatively small number of signaling systems. So as a generality
in the nervous system, as in the embryo as a whole, the way in which
cells acquire their different identities is through the intersection
of two different pathways.
The fate of no cell in the nervous system is really
preordained from an early stage. So there is no such thing as a
central nervous system homunculus. Cell identities are acquired
because of their position in an early developing neural epithelium.
And what their position really is doing is defining the environment to
which that individual neural precursor cell is exposed. So if
you're in one position you're exposed to a different set of
signals then being in a different position. So really, neuronal
generation and neuronal identity involves the intersection of
environmental signals with programs of gene expression that are going
on within the nerve cell itself. And it turns out that this vast
diversity of neuronal identities, 1,000, 2,000, whatever that number
turns out to be, is generated through a surprisingly small number of
environmental signals, where those signals operate in combinations. So
the nervous system has evolved efficient ways of using a small number
of signals to generate this vast degree of diversity.
And I just wanted to give you one principle by which
diversity comes, how you can generate many different cell types,
neuronal cell types, from just one signal. And it turns out that some
of these signals, which are secreted proteins produced by one cell
which influence neighboring cells, have been termed morphogens. So
what we're looking at here is an early primitive region of the
nervous system. This particular region is going to give rise to the
spinal cord, but if you looked in the brain, you'd see a very
So this is the nervous system. These are non-neural tissues.
There are localized sources of these secreted factors in non-neural
tissues. You can see by the shading of the color blue here which
represents a site of gene expression. And one of these proteins,
which has been known as Sonic Hedgehog for various reasons, is a
secreted protein. That protein functions as a morphogen. So what
a morphogen is is a protein that can induce or change or compose
different cell fates as a function of the different concentrations
of that one substance that a cell is exposed to. So the exposure
of a naïve precursor neural progenitor cell to a low concentration
of this factor will induce one neuronal fate. But as you double
the concentration of that factor, that same recipient cell acquires
a different fate. And so in this way, one single signaling factor,
by acting at different concentrations can induce different classes
of neurons. And so for example, the local source of this factor
establishes a concentration gradient throughout the early nervous
system, the neural epithelium. And in this particular example at
least five different classes of neurons—their identity doesn't
really matter—are generated in response to this one factor through
twofold differences in concentration. So this type of mechanism
is used again and again in the nervous system. In some cases it's
concentration, in some cases it's the convergent exposure to
two different signals that results in differences in identity.
But numerically, a relatively small number of these signals imposes
the vast degree of neuronal diversity that we see within the nervous
So I want to switch now. And you'll see that this is
going to be of necessity a relatively superficial overview of all of
these processes away from generating neurons. Let's assume that
you have generated vast numbers of neurons in the early nervous
system. How do those neurons begin to form connections? Because one
of the things that these early programs achieve are neurons with
distinct identities. And in reality, what the identity of a neuron
does is enable it to extend a long process, kind of an axon, from the
site at which it's generated into the vicinity of its target cell.
So neurons need to connect. And so in some cases—and I'm going
to show you an example from the visual system throughout some of these
comments—you can see that the distance over which a nerve cell has to
project in order to connect to its eventual target is very
considerable. Some several orders of magnitude longer than the
diameter of the cell body at that cell itself. So here we're
looking at a sort of schematic view of some aspects of the visual
system. These are the eyes. And in the retina there are neurons which
process visual information, process light, convert light into
electrical signals. And the job of these retinal neurons is to take
that information that is arriving from the environment, from the
periphery, and to transfer that information into higher centers in the
central nervous system. And in many ways it does this by extending
this long process called an axon from the site at which the cell is
generated into its eventual target regions. And then once it reaches
that target region, it then has to choose particular sets of target
neurons with which to form connections.
So there are many challenges here for a developing neuron in order
to be able to establish an appropriate wiring pattern. For example,
if you focus on this retinal neuron, it has to make a decision to
leave the retina, to extend this process out of the retina, along
the optic nerve. It then has to make a decision as to whether to
cross, as most axons do, or stay on the same side of the brain.
So there are important guide post or path-finding decisions. It
then has to reach an appropriate position within its target region.
And then it alters trajectory, and then reaches an appropriate depth
within the target region. So all of these are different environmental
problems that the developing neuron has to negotiate in order to
reach its target. And again, over the last several years we've
begun to understand the complexity of this organization, again,
has been appreciated for over a century. But what we haven't
known are any of the mechanisms, the molecular mechanisms that ensure
these precise patterns of connectivity. And the last 10 to 15 years
has revealed almost a greater degree of molecular information than
is currently processable. But I want in very brief terms just to
go through some of the thinking about how neurons, once they have
acquired an identity, begin to be able to connect with target cells.
So the business end of the neuron is a sensory motor
apparatus which is called the growth cone. So the neuronal cell body
gives rise to a long axon. And at the end of that axon is a highly
motile cellular structure, the growth cone. And so what we're
looking at here are various views of growth cones. So the axon would
then move out of below the screen and some many yards away would be the
cell body. But what you can see is that the growth cone which really
senses information in the environment and converts that sensory
information into a direction, into a vector or trajectory, is a highly
organized structure. And the general view is that the ability of the
growth cone of the neuron to navigate this complex terrain en route to
its target depends on the expression of a variety of receptor molecules
which are sensing information in the environment, mediating that
information through these receptors and converting that into directed
And so what this involves, both the reception of information
in the environment and the conversion of that into a motor
response. The growth cone has to crawl physically through
a variety of substrates. So in this process of extension
of the axon, there is a highly complicated cellular machinery
that is occurring where, for example, the actin cytoskeleton
is tightly linked to these receptors on the cell surface.
So that information from the environment is converted through
the actin cytoskeleton into directed movement. And we're
beginning to understand a great deal about the way in which
neurons, growth cones, use their cytoskeletal, use their structural
properties to influence their direction of growth.
The other thing that we've begun to understand is the
nature of the environmental symbols that influence the behavior of
axons, behavior of growth cones. Now I'm going to show you an
example from an isolated in vitro experiment that the assumption is
that same mechanisms are going on in the developing brain in situ.
So what we're looking at here in this panel is the axon
of a growing neuron and here is the growth cone. You can see that this
is a highly elaborate process, the small protrusions called Filopodia
that if this was a real time image are constantly changing, constantly
moving. These are the sensory apparatus. This is the sensory
apparatus that is looking for cues in the environment.
We know a lot about the molecules in the environment that
influence the structure and the direction of axon growth cone
movement. So the details of this don't matter, but we now
understand many, many classes of molecules that are distributed at key
points along the trajectory of a growing axon and that influence
direction directly by impinging, by imposing, changes in shape and
motility in the growth cone.
So what we're looking at in the bottom panel is the
exposure of the same growth cone to a protein that we know guides axons
and the way that it guides those axons is by inducing a very dramatic
collapse of this complicated cellular structure. So essentially it
prevents growth cones and axons from moving in that direction because
the growth cone is necessary for motility in a directionally sensitive
manner. This will then prevent growth continuing in this direction and
then the axon will move off in another direction.
Some of these molecules influence guidance if you like in a negative,
repellant way. They form no-go zones in which axons are simply
incapable of moving. Others act in a more positive way. That is
they act as lures or attractants to direct in a positive way axons
towards a particular target. Through the combination of these negatives
factors and positive factors, it's thought to guide axons from
the site in which the neuron is generated in a set of complicated
steps to the vicinity of its targets. So this have been a very
dramatic advance in understanding as we will see later on and may
have implications in therapy in the context of regeneration in the
Once an axon through these guidance mechanisms has reached
the vicinity of its target cell the next challenge it faces is actually
to select which of the small subset of neurons it's going to form
stable connections with. There may be 1,000 different potential target
neurons for that one neuron, one axon, to connect with.
How does it choose which of those 1,000 neurons it's
going to form a stable association with? Now this is an area that even
though has been the subject of intensive study is still relatively
poorly understood. It's only in the last five years or so that we
have any understanding in the central nervous system in the brain of
the mechanisms for forming functional synaptic connections because
communication between nerve cells depends on the formation of these
functional connections. There are many problems inherent in this
process of recognition of how you recognize the target cell to form
So in various schematic ways, there are sort of where type questions.
That is this is one target cell. This in-growing axon has chosen
to form a connection on that one target cell, but not on a neighboring
cell which would be off the screen here. So that is the first type
of question. Which cell do you choose to form a connection with?
The second type of question which is very important for the function
of the neuron is where do you form the connection. Do you form
the connection close to the cell body of that target neuron or do
you form because neurons are such highly polarized structures way
out from the distal processes of the so-called dendrites of the
neuron? So there are questions of sub-organization as well as which
cell you choose.
Frankly we don't have a good understanding in molecular terms
of how these processes operate even though we do know that there's
a high degree of stereotypity of selectivity in those processes.
So what the field currently trying to understand in a way that I
think will eventually be important for understanding how circuits
control behavior and how those behaviors are eroded in disease is
understanding the biochemical mechanism that is essentially a recognition
process between the arriving neutron, the pre-synaptic neuron and
its pos-synaptic target. We have little information yet on the
nature of the molecules that drive this process.
But interestingly and I'll come onto this later, the few molecules
that have been implicated in this process are known to be mutated
in certain forms of human neuro-developmental disorders. So it
begins to suggest that actually understanding the machinery of synaptic
connectivity may say a lot about the normal and pathological function
of the human brain. I'll elaborate on that point.
So the final step in this brief overview of the wiring
diagram in the brain occurs after neurons have made connections with
their target cells. You might imagine that this is the end of the
process. Once you have generated the neuron, you've managed to
reach the target region. You form the connection with the target
cell. The job of development is done. But it's very far from
done. As we'll see, there are many processes that have to operate.
One of those processes relates again to this basic problem
I started with of numerology. That is in order for a circuit to
function appropriately, there has to be a precise matching of the
number of neurons that are generated in one region and the number of
target cells or target neurons that are found in a completely different
And one of the very surprising things that emerged some 50 years
ago is that the nervous system is extremely wasteful in the generation
of neurons. In fact in most regions of the nervous system, two
to three-fold more neurons are generated than are eventually incorporated
into functional circuits which would seem a wasteful process.
But one of the rationalizations of that process has been
that perhaps one of the things that permits one to do is to achieve
numerical matching between two sets of interconnected neurons. If you
generate neurons in larger numbers, those that are generated in excess
become dispensable and can be eliminated. There is a lot of evidence,
cellular and molecular evidence, that this type of process occurs and
this is generally known under the term of neurotrophic factor
The basic idea that seems to operate is that you have a
restricted target cell and many neurons that have the potential to
innovate that target cell. But what happens again and again during
brain development is that only a small set of those neurons that are
originally generated eventually form stable connections with that
target cell. The reason at least that this occurs in part is that one
of the things the target cell is doing is communicating back to the
There is a two-way process of communication and the target cell
is producing factors that support the survival of the neuron and
it's producing those factors in limited amounts and limited
availability. So in a sense, this target cell produces only half
as much of this survival factor as is needed to support the entire
compliment of neurons. As a consequence through a competitive process,
only perhaps 50 percent of those neurons that are alive in the vicinity
of the target cell form stable connections. What we'll see
in the next section is that this process of competition, excess
production and competition, is really paramount in linking the genetic
programs of neuro-wiring to experience and activity in the way that
experience and activity sculpt these basic projections.
Without going into details, we know the basic elements of this
competition, target-celled derived support factor hypothesis. In
many cases, we know the nature of the molecules that promote cell
survival. One of the dramatic advances in all biology over the
last 10 to 20 years has been the appreciation that in fact the default
state of most cells in the body is not to survive, but to die.
There's an intrinsic death program that is inserted
into every cell. Cell survival really only is permitted under
conditions in which that intrinsic death program is suppressed and is
subverted and the first inkling of that information in fact derived
from these sorts of experiments in the nervous system. So we know the
nature of these neuronal survival factors and we know a lot about the
biochemical mechanisms by which they promote cell survival. This is
the first example really in a normal developmental epoch of ways in
which competition and interactions between cells shapes this genetic
programming of the wiring diagram.
I'm going to move now unless there are questions or
comments that I could elaborate on from this simplistic but
nevertheless I think valid idea that genes in large part program the
basic wiring diagram of all nervous systems from invertebrates to
vertebrates, from mouse to man. Many basic aspects of the connectivity
are programmed in a way that involves serial developmental decisions to
give this basic neural blue print. But at that point, the precision of
connections, which connections are maintained, which connections are
reinforced, which are eliminated then begins to be impacted in an
extremely profound way by environmental signals.
So I want to begin to talk now about how activity of
nervous systems, how the experience and the environment shape these
connections. Again I'm going to use the classical example which
emerged from studies by Hubel and Wiesel in the 1960s and the 1970s
focusing on the organization and structure of the visual system and the
influence of environmental deprivation on the structure because I think
that there are many, many examples of this general paradigm but that
the first realization came from these classical cellular and
We're now back in the visual system. These are the
eyes. This is the optic nerve projecting to a set of relay nuclei to a
second order neurons in the thalamus and those thalamic neurons then
relay visual information from the eye via this one relay station to the
cortex. So most vertebrates can extract information from the visual
world and use two eyes to do that.
How does the brain extract information from the left visual
field, the right visual field, keep that information separate as it
begins to form these projections, form these connections, and where is
that information integrated? One of the important things that occurs
is that you keep the information from the left eye and the right eye
separate at many of the early processing stages in the developing
brain. What you can see is as one traces through and then looks in
higher magnification, that an input from say the right eye here will
eventually project to a region of cortex that is spatially distinct
from that region of cortex that receives information from the left eye.
What the great discovery of Hubel and Wiesel together with
Vernon Mountcastle in the somatosensory system was that the cortex is
basically organized in columnar fashion. Information doesn't
arrive in an indiscriminate, anatomically mixed fashion. Information
from the two eyes is physically separated. One can see that
physiologically as Hubel and Wiesel first saw that but you can also see
For example, if we provide a tracer into one eye such that
that tracer is incorporated through all of the neurons that form that
right eye circuit, you can then see the consequence of the projection
of that right eye in relation to the unlabeled left eye. So that if we
look here, this is a cross section through a mammalian cortical
structure. This is true of humans. This is true of primates. This is
true of cats, many mammalian organisms. What we are looking at are the
terminal fields of axons that receive information let's say from
the right eye. They would be shown as these light patches here.
What you can see is the cortex consists of the mosaic of light and dark
patches which is a reflection of information coming in from the
right eye as opposed to the left eye. This is a relatively mature
state. This is what 13 week post-natally in this cat experiment
But what is interesting is if you look at a much earlier but still
post natal stage, what you can see on the top here is that these
stripes or banded patterns don't exist. What the implication
of that is is at this early developmental stage information from
the left and right eyes is arriving in the same spatial region within
the developing cortex. What you can see is that over the intervening
11 weeks of post natal development in a so-called critical period,
the information, the axons from the left and the right eyes are
segregating to form these distinct domains.
This is a process of development of connectivity that is occurring
in the post-natal period which then follows most of the earlier
embryonic patterning mechanisms that are described in the first
section. What is particularly dramatic about this sort of structural
organization of visual input is that it's critically dependent
on visual experience. An early set of classical experiments looked
at the consequences of eliminating visual input into one of these
eyes and examining anatomically and physiologically the consequences
for the structure of the brain. What happens if you deprive one
eye of the normal sensory information that it receives? And you
see very dramatic changes.
So we are now going to switch orientation and we're
going to be looking at top down images of the brain, of the cortex with
sections or slices cut through in this plane. What you see here is in
the top panel—I hope you can see that from the back—that you have
again these alternating stripes, so-called ocular dominance columns of
left eye, right eye where the width of each of these stripes which is
an anatomical representation of information coming from the two eyes is
roughly equally proportioned, that equal black stripes and white
stripes here. This is a diagram showing this mosaic of information.
What you can see in these intervening panels is that
structural reorganization of information in the brain in the cortex has
a consequence of monocular sensory deprivation, depriving one eye of
visual input. For example here, and it really doesn't matter, what
you can see in this case is if the eye that was represented by these
dark stripes was deprived, you can see here that there's a massive
over representation of the structure, the inputs, from the eye that is
still receiving visual information. The white patches greatly exceed
the dark patches.
Conversely if you design the experiment in a different way
and you deprive the light patch eye, you can see that the dark patches
prevail. This is very dramatic evidence that visual experience
produces a structural change in the brain. One of the things that one
can now begin to understand is the nature of the process by which
environment and experience produces structural changes in the central
nervous system in the cortex. This is just a diagram of what we were
looking at in real images before.
Early on the information from the two eyes is essentially
overlapping over this post natal, critical period. The information
gets segregated into distinct ocular dominance columns in the
developing cortex. And that under conditions where sensory information
is eliminated from one input, then the other input predominates. So
these are gross structural changes in the organization of the brain
that are the consequences of presumably the inability of experience and
activity of those neurons to maintain a spatial territory.
You can actually see this influence of experience and the
environment at the level not of just domains of the cortex but
individual neuronal branching patterns and morphologies. These are
just four diagrams showing essentially the normal change in development
of an axon, a nerve that is going to innovate the cortex and the
consequence of deprivation.
On the left-hand side here, we've traced the terminal projections
of one of these axons arriving in the cortex conveying visual information
in a young post natal animal. You can see that the region of space
or cortex occupied by this axon that it's relatively broad that
the density of terminals of branches in any given region is relatively
small, relatively low.
Now as the animal matures under the consequences of normal
visual experience you can see that there's a dramatic
change in the shape of that projection. A much smaller region
of the cortex is now innervated, but that region that is innervated
now receives a much higher density of axonal branches and
synapses. So this is the process of post natal structural
reorganization that is occurring.
We know that this structural reorganization is again
dependent on experience upon sensing the visual world because if we
deprive one eye then you can see that at the level of an individual
neuron those structural changes are very dramatic. The neuron has few
axons, few terminals. We are seeing this level of structural
reorganization in the nervous system as a consequence of visual
experience at many, many levels.
Here we're looking—and I'm going to emphasize
this point because I think it's one of the major features in the
way in which environment, the experiential world influences the
structure of the mature nervous system—at the level of the axons that
are arriving in the cortex, but we can also see this at a finer level
of resolution if we look at the target neurons that are going to
receive that information.
I'll do this first. Here is one of these cortical neurons.
The cell body, it has a very extensive set of processes called dendrites
and the synaptic input, the information that is coming into this
neuron is occurring on a series of very small micro structures that
come out from one of these dendrites which are so-called dendritic
spines. The spines here, these protrusions, are really the units
of synaptic information. Each of these spines is going to be occupied
by an incoming synaptic terminal.
We know that some of the same activity experience dependent changes
that I was showing you in the previous slide at the level of the
pre-synaptic terminal also influenced the dynamics of these spines.
Whether these target neurons have many spines, have few spines,
these are very dynamic cellular structures which come and go as
a consequence of activity. Both on the pre-synaptic input side
and the post-synaptic target side, experience and activity in the
circuit is having an dramatic impact on the structure.
This information all of which is derived initially from the visual
system raises the question of whether this is something special
about the way the visual system works, or whether in fact
all sensory systems are subject to the same structural change
in organization of the brain as a consequence of sensory information
coming in from the environment. There are many, many examples
as one moves out of the visual system that the same thing
is true. I'll show you just one example from the auditory
This is again a slightly varied organization here, but
we're now looking at a map of a region of auditory cortex. This is
the region of the brain that processes normal sound, auditory
information. The wonderful thing about the auditory system as opposed
to the visual system is that sound is tuned according frequency.
Different regions of the auditory cortex are tuned to optimal
There's a so-called tonotopic map. Different sound frequencies
get projected to different regions of the auditory cortex. By applying
a single sound you can make that region of the cortex that receives
that particular sound frequency. That's what we're looking
at here in an early post natal rat in fact this is.
Now the relatively large region of cortex associated or
devoted to that particular tonotopic frequency. If we look some 34
days later, the region of cortex that is devoted to that same sound
frequency has reduced in a very dramatic way. This looks a lot like
what we saw in the visual system. We know that auditory experience,
the sound that we experience, over that critical post natal period has
a dramatic influence on how this auditory, tonotopic map forms.
Because if we now apply to an experimental situation, apply in a sense
a white noise preventing the auditory system from extracting normal
variation in sound frequency, then applying this distracter noise
produces a very dramatic slowing of the normal maturation of this
We're now looking at the same map here but under
conditions in which a distracter noise had been applied. You can see
that not only does deprivation of visual information but deprivation of
important auditory information erodes the normal formation of the
structure of the brain, the structure of the cortex. You see this
same information, this same principle, occurring in all sensory
What this means I think is that during this critical post
natal period information coming from the environment and from the
visual senses, the auditory senses, the tactile senses and the
somatosensory system, taste, smell, all of this information is
converging on the central nervous system and providing these structural
refinements in the basic wiring diagram that are essential for accurate
perception of the environment, accurate performance of motor commands
in response to that information. This I think highlights what
we've known for many years that this critical post natal period is
essential for the appropriate structural information within the nervous
CHAIRMAN KASS: This sounds as if this is mostly a certain kind
of openness is then restrained and pruned and that there's a
greater sort of amorphousness which then becomes more specialized as a
result of this experience. Have I gotten that particular point right
PROFESSOR JESSELL: Yes, perhaps the easiest way of showing
it is just to go back to this image which is essentially a pruning
image. What is happening at these post natal stages in development is
that the map is roughly correct. So visual information is coming into
the visual cortex and not to the auditory cortex. But the fine details
of the working of those cortical structures is not sufficient to
achieve this rough map. You have to proceed. You have to achieve a
precise map. That precision is achieved by this pruning process.
So in a sense what we're looking at here as you go from
young to mature is the pruning of one neuron. That has functional
consequences because then you achieve a much greater degree of point to
point precision in connections. This pruning process is activity, is
experience driven. Without that experience, without the range of
information coming in from the outside world, this pruning process
fails to occur. We can see that at the single cell level and we can
see that at the level of the auditory example.
CHAIRMAN KASS: May I just follow up? Would there be—I don't even know what I'm asking here, but is there something
that you could call pre-natal experience that is at work even before?
Sound I suppose is still transmitted intrauterinely. Visual would
be a different matter. But do we have environmental and "intrauterine"
experiential things that are already doing this or does the major
effect take place after birth?
PROFESSOR SANDEL: And what about the Mozart effect? Even
if that's not true, would that be an instance of this?
PROFESSOR JESSELL: Yes. I haven't mentioned it and
stressed the post natal period, but there is strong evidence that
this activity-driven wiring of the nervous system occurs during
fetal development as well as post natal development. There is very
strong evidence in one of the articles I distributed.
Carla Shatz is one of the people who has really provided
some of the strongest evidence that in fetal development the retinal
ganglion neurons that are first arbiters of processing of visual
information are firing in patterns during embryonic development that
is thought to be important for setting up perhaps the first aspects of
organization superimposed on this basic genetic wiring program.
That is certainly true for the visual system. I think
there is good evidence that is true in the auditory system. Whether
it's true in some of the other sensory systems, the evidence is
less. So this process even though it's been most heavily studied
at a post natal period for reasons of accessibility probably is
beginning during the embryonic stage and when it begins you can put
limits on to in the nature of the basic connections that have to be
formed before the information from the environment can even reach
relevant areas of the cortex. But it's a relatively early process.
DR. ROWLEY: But if I can follow on with that. It
was my impression from reading Carla's article that what's
formed are some of these intermediate connections or the way
stations or the relay stations rather than the specific connection
with the fine processing neuron in the cortex.
PROFESSOR JESSELL: Yes.
DR. ROWLEY: In her example in the visual cortex. So you
set up the systems that are necessary already before birth so that
these intermediate processes that connections have been made and then
the pruning of the final one is what's then done after birth.
PROFESSOR JESSELL: Yes, that's absolutely correct.
The system that Carla is looking at which is shown on this slide back
here, I've been concentrating on the cortex which is the final
target. Carla has looked at this intermediate thalamic relay station
because those are the targets of retinal ganglion neurons that are
spontaneously active during fetal development.
I suspect that wherever you look you will find evidence
that the activity experience dependent structural changes traditionally
this has been looked at first in cortical structures. We now know
it's true in subcortical structures in the thalamus. I suspect
even at the level of the first sensory relay station, perhaps even in
the retina itself, activity is having an influence in terms for example
of the morphology of neurons or fine details. I suspect that this is
happening in a very pervasive manner and where you look depends on what
type of experimental system accessibility of that particular region of
the nervous system.
PROFESSOR SANDEL: You've been speaking about the
plasticity in the early post natal period. Do we know when it stops?
PROFESSOR JESSELL: Yes.
PROFESSOR SANDEL: When experience dependent changes no
longer affect the structure of the brain?
PROFESSOR JESSELL: That's the next section. So maybe
I can come onto that. Yes. The answer is that if you'd asked me
this or asked the field this ten years ago, the idea would have been
that this critical period closes at some point two to three months
after birth in an experimental animal. It perhaps closes in the first
several post natal years in the human infant. What we now know is that
to some extent that process of plasticity persists throughout adult
life. I'll give you some examples of that. Probably I think as a
generality the nervous system is most plastic at early stages and
plasticity is essential for connectivity in the way that we've seen
in an immediate post natal period. But there are striking functional
elements of plasticity albeit at a reduced level even in the mature
CHAIRMAN KASS: Dr. Jessell, would you like to complete the
presentation? We can take questions then.
PROFESSOR JESSELL: If they are burning questions, now is a
good point. We've reached the end of this stage.
CHAIRMAN KASS: Bill Hurlbut and then Gil.
DR. HURLBUT: In saying that there is a longer phase of
plasticity at some point whether now or in your further presentation,
can you talk about the possibility of actual revisions like the slide
you showed Mike Merznich's information? I know Mike is very
interested in revisions of neural process.
PROFESSOR JESSELL: Yes, I will comment on that perhaps in
this context of the adult stage and what some of the Merznich
observations, some of those implications are. Yes.
CHAIRMAN KASS: Gil, very briefly. Then I think we should let
Dr. Jessell complete.
PROFESSOR MEILAENDER: Yes. Whether I
can make sense of this question or not I don't know.
I don't belong to the party of rationality. But could
you or would you use in describing this process of development
a word like optimal? Is there an optimal point anywhere along
the way? Or is that not the kind of word that you would use?
Is it just a process that you describe in which one couldn't
find a place to use that sort of word?
PROFESSOR JESSELL: I think what we've learned is that
development as I'm describing it is a process of gradualism. That
there is constant change as a consequence of influence of the
environment. To use the word "optimal" presupposes to some
extent that we know how the circuit should function in all its
aspects. What we see are erosions of performance in behavior that
presumably can be linked to changes in circuits. So that is
What the optimal wiring of these circuits are I think we
don't understand. So dramatic perturbations I think we can
interpret. As we'll see, maybe it's a matter of give and take
that in considering for example the plasticity of the adult nervous
system. One is balancing two forces. One is that you want some
constancy in connections because that constancy allows you to perform
at a high cognitive level. Learning and memory are thought to be
encoded at least in part in the constancy and the strengths of
individual connections. So constancy there is a desired attribute
perhaps something approaching optimal.
On the other hand if you think about regeneration of the
nervous system under conditions of lesional injury, then the nervous
system, that constancy becomes a liability in terms of the ability to
reform connections. Where optimal is along that sort of line, I
don't know and I don't think anybody perhaps knows at this
I'd now like to come onto the question that we were
just discussing which is over what period does plasticity really
persist. Is there as classically viewed a critical period and once you
reach the end of that critical period in post natal development, the
wiring diagram of the brain is fixed and activity simply operates on
the structure that exists without having the ability to change it
further? Work from Michael Merznich and many other people I think has
very dramatically changed our view of the extent of plasticity in the
What I was going to do is to talk about three aspects of
this balance between constancy or stability and change in an adult
context in three different sections. One comes back to what we were
talking about earlier in terms of just the generation of neurons. The
second is the reorganization of circuits. The third is the
regenerative capacity of the nervous system as a function of age.
One of the dogma that has been overturned in the last 10
to 15 years relates not only to the reorganization of circuits
but to this idea that neurons are born early in development
and then once they're born the nervous system has acquired
its mature cohort of neurons and there's not much you
can do to change that situation. I think that now we know
that that is not the case and that there are certain privileged
sites within the brain that are capable of new neuronal production
even in the adult stage. This obviously has many implications
in a clinical, in a therapeutic way.
If Rusty Gage who I think was due to be here, he would
expounded on this view because he's been one of the major
contributors. But in his absence, I'm going to really review very
briefly some of the evidence that I think provides persuasive evidence
that at least in the mammalian brain although I think whether this is
really true and the extent to which it's true in human brain is
still a matter of debate that in the mammalian brain, in mice and many
experimental animals, neurons are produced in the adult nervous system,
in the adult brain.
But they are not produced everywhere. There seem to be two
privileged sites where neurons can be produced. One of those is in a
region in the forebrain in the subventricular zone. The details really
don't matter, but many of these neurons will then migrate into the
olfactory bulb, one of the regions that is involved in processing
sensory information. It's been known for many years that neurons
that convey odor perception from the external world turn over even in
the adult state. These are the primary sensory neurons.
What has been appreciated more recently is that they are
target neurons, the neurons that have to receive that incoming odor
information also turn over at some rate. So the olfactory system for
whatever reason and one might speculate on that is a privileged site
within the human brain in which neurons are constantly being
replenished. What impact that has on one's ability to respond to
odorant information to pheromone information, the environment, is
something that could be discussed. What this shows very clearly is one
site in which neurons are produced in the adult brain contravening
existing dogma that had persisted for many decades.
There is also a second site and so far only a second site
of new neurogenesis and that is found in a cortical structure called
the hippocampus. This is an area which has been implicated in many
interesting cognitive functions, learning and memory amongst them, but
also mood and emotional disorders. It's very clear here that there
is a small group of precursor cells that in the adult animal in just
the same way that we've seen in the embryonic period of
neurogenesis, there are progenitor cells which make the decision
whether to leave the cell cycle and become post mitotic neurons in the
You can visualize them with various molecular tricks. What
people now think that at some slow rate these neurons are
produced. They begin to acquire all the hallmark structural
features of neurons and there is some, albeit weak, evidence
that these neurons can actually contribute, reconstitute themselves,
into functional neural circuits although I think it remains
unclear as yet what the functional consequence or contribution
of these adult generated neurons is.
But this has been a very surprising set of observations
that initially met with some resistance and then some over enthusiasm
and interpretation. But I think that it's now clear that these two
regions of the adult mammalian brain can produce new neurons.
There are further implications of this observation in terms
of plasticity of the mature brain because the production of neurons
for example in the hippocampus in the adult brain doesn't proceed
at a constant rate. It itself, this process of neurogenesis, can be
influenced by environmental stimuli.
Rusty Gage is one of the people who've show that
rearing experimental animals in deprived or enriched environments can
have a relatively significant impact on the rate of new neuronal
production in this region of the hippocampus. One of the experiments
that Gage performed is to rear mice in a relatively deprived
experimental laboratory environment or to give them enriched
environments or environments in which exercise and motor systems are
activated at a much higher level.
You won't be able to see this because of this technical
problem, but maybe if we concentrate of the middle panels here, each of
these black dots represents that region of the hippocampus where new
neurons are produced and each black dot is a newly generated neuron
under these control conditions and under conditions of exercise or an
enriched environment. Here you can see that stimulating the
environment of the animal produces a significant increase in the rate
of new neuronal production. Again this is a much later example of the
way in which an animal's environment influences plasticity in the
DR. ROWLEY: I was wanting to ask you to define more
precisely the age both of the animals and of the equivalent age in
PROFESSOR JESSELL: Yes. In these animals, these are mice
in this case. You can see the same thing in experimental rats.
These are so-called mature which would be two to three to four months
of age, something like that. The issue with humans is, I think,
at a more fundamental level and there are people more expert than
I who could address this as to whether the same process that we
see in lower mammalian species occurs in a significant way in the
adult human brain. I think that is a matter of debate.
It's clear that there are progenitor cells that are proliferating
in the adult human brain. The question as I understand it is whether
those progenitor cells produce, overt fully authenticated post-mitotic
neurons in the human brain at the rate that they do in the lower
mammalian brain. This phenomenon can be seen at six months of age
in mice. This is a very robust phenomenon. It's not the trailing
edge of a developmental process. I think new neurogenesis is really
occurring at a relatively constant level probably until middle age
for the mouse. But again there are fundamental issues as to what
extent—and maybe other people will have views on this, to what
this really occurs in the human brain.
So one form of plasticity change in the human brain as a
consequence of the environment is seen through simply modifying the
environment. But there are also experiments which suggest that
pharmacological intervention can also influence the rate of
neurogenesis in the hippocampus at least in experimental animals.
Eric Nessler and Ronald Dumond, some years ago, not too long ago,
came up with a very striking observation that anti-depressant treatment
using a serotonin uptake inhibitor, Fluoxetene, has a dramatic effort
on the rate of neuronal production in the hippocampus in this same
system. I've just taken one image which is exactly the same
type of experimental approach. Under the control conditions, there
are relatively few of these black dots. You probably can't
even see them there.
Under Fluoxetene treatment, then the rate of neurogenesis increases
in the hippocampus. This suggests that clearly these drugs have
behavioral consequences and raises the question of whether some
of the behavioral consequences of mood-altering drugs are in fact
a consequence of changes in the rate of new neuronal production.
Clearly these drugs may have many effects. So this could be an
incidental rather than a causal influence.
My colleague at Columbia, Rene Hen, has performed an
interesting series of experiments recently that were reported in
Science last year which actually while not proven at least keep
open the idea that adult neuronal production is in fact perhaps a
causal contributing factor to changes in the behavioral consequences
following serotonin uptake inhibitors. This is a very active field at
the moment, but I think it have many people galvanized about thinking
not only about natural experiences but also the way in which
pharmacology and drug treatment influences this aspect of brain
plasticity and behavior. This is a recent set of observations so the
consequences of this I think remain to be discussed and thought about.
This is one example which really takes the information.
DR. HURLBUT: Those studies are on mice.
PROFESSOR JESSELL: These are on mice.
DR. HURLBUT: And are these mice that are in any sense
depressed so to speak or are they in an enriched environment?
PROFESSOR JESSELL: Yes. There are a behavioral assays
that the Hen group have done in particular where they've
used certain behavioral, open field trial responses. It's
a complicated issue. One of the things that the Hen study
tried to do is actually prevent adult neurogenesis and then
ask about the behavioral consequences of Fluoxetene administration.
One of the ways they tried to do that is to irradiate the
hippocampus, killing the progenitor cells, preventing neurogenesis
and they have some behavioral evidence that many of the behavioral
consequences of Fluoxetene treatment are belated as a consequence
That raises all sorts of additional questions about whether
irradiation is specific and whether you can contribute the
effects of irradiation to the loss of neurons and whether
the behavioral parameters being measured in mouse really are
a reflection of the state of elation or depression as viewed
in a human. I think all of these are open questions and hopefully
will emerge with further studies.
DR. HURLBUT: So essentially you are saying that there is
to date no evidence that an otherwise normally functioning enriched
mouse would have increased rates of neurogenesis under an SSRI.
PROFESSOR JESSELL: I think many of these things are
suggestive correlations at the moment that drugs and environmental
experience that change the behavior of the mouse change neurogenesis.
The Hen experiment to my knowledge is the experiment that most closely
links causality or implies causality in the process, but I think Hen
himself would not argue that that case has been proven at the moment.
I think there are experimental designs that will emerge over the next
two to three to four years that will establish causality or not. Then
I think things become interesting.
This has been plasticity in the adult context viewed from
neuronal production. There is extensive evidence that aspects of
circuitry are also plastic beyond the traditionally viewed critical
period. We've discussed the Merznich type of experiments and
Michael Merznich has been the person who has promoted this idea most
persuasively. It again comes back to mapping in regions of the cortex,
particular regions of a peripheral sensory receptive field.
Merznich has done this to a great extent in the
somatosensory system where individual regions of the body surface can
be mapped to particular locations in the somatosensory cortex. Then
the basic gist of these Merznich type of experiments is to change the
level of information that is applied to that peripheral receptor field
by training in way or another and ask in a mature central nervous
system in the mature brain whether the cortical representation of that
peripheral receptor field changes using physiology and to a lesser
extent using anatomy.
Then there are striking examples that the cortical
representation of a given receptor field for example on the digits in a
primate, in a monkey, changed dramatically as a function of training.
So here is the receptor field on the digits of a monkey. This is the
normal region of cortex that receives that information. This darkly
shaded area represents the normal area, the normal region of cortex,
that receives information from those three receptor fields on the
digits. After training you can see a very significant expansion in the
area of cortex that processes that information.
This is a functional reorganization of the nervous system
as a consequence of experience or training. It raises the issue of
what is the structural basis of this. Is this a structural
reorganization in the way that we've seen at earlier stages of
development in the visual system or is this really a functional
reorganization? Are some synapses normally just not operative and
sitting there in a quiescent state? But upon training, these synapses
suddenly start to work? So at a physiological level, you see a change
in the map. These are questions that I think are currently being
The extent to which this clear and established functional
reorganization which is the important thing reflects a structural
change or reflects changes in the efficacy of synaptic communication
between neurons. Merznich's group has some evidence for structure,
but whether structure accounts for all of the dramatic changes in
mapping of sensory inputs I think remains to be seen. Nevertheless
this very clearly, I think, shows that there can be reorganization of
circuits as well as simply the generation of neurons at a much later
stage in an adult stage.
Then finally I want to deal with, if you like, the flip
side of plasticity in the adult nervous system. The ability of the
nervous system to adapt to a changing environment probably is a good
thing. It allows you to optimize perhaps circuitry in relation to
particular environmental conditions.
But one of the things the nervous system is not good at
doing is reorganizing in the wholesale way so all of the processes I
described at early stages in development, the extension of axons, the
ability to form connections, the ability to refine those connections in
a very dramatic way, decrease dramatically with age. One of the major
problems from a clinical perspective is the relative constancy here.
I've focused on examples were things can change. Neurons can be
But by and large, the mature nervous system is a relatively static
structure. This has dramatic consequences following damage or injury
to particular regions of the nervous system. In one well-talked
about example in spinal cord injury, one of the reasons that people
with high spinal cord injuries recover so poorly is because of a
poor regenerative capacity of the nervous system. This is if you
liked limited plasticity. Damage to a particular region, all of
the descending fibers from the brain that are necessary to activate
the motor system to restore motor control, the extension of those
processes across a lesion or scar region is extremely poor at the
moment. This again has been appreciated for 100 years.
Over the last ten years I think partly through work on
developmental mechanisms, there is now some hope that plasticity in
this context can be enhanced dramatically by changing the environment
in which regenerating axons are trying to grow. One could view this in
two ways. One is that perhaps the failure of adult neurons to extend
axons effectively to recover function is an intrinsic property of those
neurons. They just somehow with age lost the capacity to grow axons.
That probably is not the case.
A major influence on the inability of axon regeneration is nothing
to do with the neuron itself, but is the fact that the environment
of that neuron is now extremely non-permissive for axon growth whereas
at an earlier stage in development, it was highly conducive to growth.
The last five years or so has seen very dramatic advances in understanding
the molecular basis of that non-permissive adult environment. It
turns out that many of the supporting glial cells in the nervous
system—we focused here on neurons—in particular a class of cells
called oligodendrocytes express proteins on their surface that will
inhibit axon regeneration.
Since most axons are trying to grow in the mature central
nervous system in the highly myelinated oligodendrocyte rich
environment, the reason they don't grow well at least in part is
because oligodendrocytes with maturity acquire proteins that inhibit
Again the details don't matter, but this slide is
really just to show that there are now some molecular reality to
proteins that are expressed on the myelinating oligodendrocyte and
receptors expressed on the sensitive neuron. Many studies now are
underway to try and eliminate thes proteins and see whether that has
the ability to enhance some regeneration. This is viewed from a
clinical perspective to recover motor function for example in cases of
spinal cord injury, but I think it has interesting implications because
it comes back to this issue about what is optimal in terms of stability
and plasticity in the mature state. If you could find ways of allowing
perhaps in order to maintain faithful function of neural circuits, you
have to find a way to cement them in place.
The downside of that fixation process is the inability to
recover function from more dramatic traumas to the nervous system.
What happens if we can now unleash plasticity to a much greater extent
than had previously been possible? What will be the consequence in
terms of other aspects of nervous system function, cognitive
processes? Will one generate complete disorder? Will animals become
more intelligent as judged by behavioral methods under conditions where
they can reorganize circuits in the mature state?
I think these are issues that one is only just beginning to scratch
the surface with. With the technical abilities that come
in part through molecular biology over the last five years,
one will likely be able to manipulate circuitry in the adult
central nervous system in a much more profound way than has
been possible for the last century. Thinking about how one
then designs, at least initially experimental tests to examine
the consequences of reorganization in the mature state, I
think is something that needs considerable thought. The last
thing I want to do is if I still have five minutes. I can
stop at this point.
CHAIRMAN KASS: Why don't we stop and take a few questions
if that's all right?
PROFESSOR JESSELL: Okay.
CHAIRMAN KASS: Janet.
DR. ROWLEY: I'd like to hear the rest of what's
been prepared please.
CHAIRMAN KASS: Okay. All right.
DR. ROWLEY: We all can have a shorter lunch.
PROFESSOR JESSELL: This will be two minutes so hopefully
it won't impose too much. What I've talked about so far has
really been normal developmental processes, the influence of
environment and genetic programs and predetermination on the structure
and function of the nervous system. But this has as we've begun to
talk about in regeneration a clinical consequence. One of the other
things that has emerged I think from understanding normal molecular
genetic programs that have developed is that those processes are likely
to be precisely the processes that go awry in many neurological and
psychiatric disorders. This is a very new field, but I think there are
enough small examples to indicate how this will really change or
produce a convergence of clinical neuroscience and these basic
One example just comes from looking at many classically defined
neurodevelopmental or cognitive disorders. In the few cases where
genes associated with those disorders have been identified, many
of those genes affect precisely the processes that we've been
talking about this morning, the process of neuronal identity through
genes that control cell identity, transcription factors, the nature
of signaling factors, the nature of synaptic proteins, so two examples
that I won't stress.
Some of the proteins that I've mentioned briefly that
are involved in synapse formation, how one neuron communicates
to another, it's been shown that mutations in those genes
are associated with forms of autism and with the Asperger
Syndrome. Signaling factors that are involved in neuronal
communication have been associated, albeit not completely
persuasively, with schizophrenia.
In the case of transcription factors, one has the surprising
example that quite highly complex, cognitive disorders relate to
genetic defects in genes that are DNA-binding proteins that control
patents of gene expression. So two good examples of that exist.
One is a syndrome known as Rhett Syndrome which again if
you like is a variant form of autism. There is a gene that probably
accounts for the vast majority of Rhett Syndrome cases. These are
children who acquire gradually over the first two to three years of
post natal life progressive cognitive impairments, stereotypic motor
behaviors. They lack function of a gene involved in methylating many
target genes. Some of those target genes are now known and one of
those are the trophic factors that we talked about in the context of
keeping neurons alive.
An even more striking example is in the case of genes that
influence human ability for language and integration of spatial
information. So there is a syndrome described by Tony Monaco and by
Vaga Cadan associated with facial abnormalities and with dyspraxias.
There is a clear pedigree. So these people have abnormal impaired
language acquisition. The gene associated with that pedigree turns out
to be a transcription factor which is expressed and involved in the
determination of neuronal identity.
This raises very profound questions of taking a disease
which appears highly specialized in a cognitive manner and finding out
that the gene that causes that is a gene expressed at a relatively
early stage of development, probably involved in establishing some
aspects of circuitry. One of the challenges that I think is going to
face the field is now understanding causally how the mutation in that
one gene influences a relatively specialized set of cognitive
Another example is Williams Syndrome which is associated
in contrast to for example Down's Syndrome and this KE
language defect with in fact an over elaborate use of language
by children. They have a very extensive vocabulary. They
are extremely articulate, but they have very poor ability
to extract and integrate information from a visual world.
This is a very highly localized cognitive disorder that has
been studied by Ursula Belugi in particular. All of the children
who have this cognitive disorder have a small chromosomal
deletion that probably eliminates in large part a transcription
factor that controls cell differentiation.
So here is another example where very specialized cognitive
dysfunctions are mapping to genes that we can now begin to understand
in terms of their role in developmental processes. Yet there is a very
large gap between understanding the nature of the gene, the neuron, the
circuit and the behavior. But I think over the next several years as
human genetics begins to give us more information on the nature of
these behavioral disorders many of which affect this early childhood
period, we're going to be faced with trying to link in very
relevant clinical context some of the early developmental mechanisms
that we've talked about with some of these behavioral events.
Perhaps that's all I want to say. I'll stop there.
CHAIRMAN KASS: Thank you very much. I'd like to run over
and as Ms. Janet says we'll have a slightly shorter lunch because
we shouldn't waste the opportunity of having some conversation with
Dr. Jessell after this very comprehensive and very stimulating
presentation. Thank you. Dan Foster please would you start and could
we get the lights?
DR. FOSTER: I have just—I don't know whether you
can answer this in 30 seconds, but it's always intrigued
me. From the very beginning, you've talked of a necessity
of scaffolding and we move here in the spinal cord and you
have some sort of signaling, a way that neurons can grown
and so forth. I understand a little bit about oligodendrocytes
and astrocytes and jagged and notched and so forth.
My question is something different in terms of therapy.
At least in rodents, it looks like that if you inject a neurogenic
stem cell even in a peripheral vein that it's going to
circulate and get to the brain and then somehow will target
to a damaged cell—it might be a stroke or a glial blastoma—you put a human tumor in there. So the more I listen to
you it's almost as though they are chemotactically or
someway attracted rather than going on scaffolding. I'm
just dying to know what you think about how that process goes
in ten words or less.
PROFESSOR JESSELL: The first slide I showed I think
illustrates the nature of the problem a little bit. At early embryonic
stages the brain is small. The adult brain is extremely large. So
just distance imposes great challenges. The environment of the adult
brain is completely different from the embryonic brain. Many of those
scaffolds that we talked about have disappeared in the adult brain.
So in an example that you describe where cells seem to be
smart enough to get to the right place, I think we have very little
understanding of how that homing behavior is actually achieved given
that the normal developmental cues are now missing. I would say that
the evidence that that happens in a highly efficient way is not so
I think it can happen whether it happens as efficiently as
it would in a normal developmental context so maybe only one in a
million perhaps by some random probabilistic nature ends up in the
right place and then those cells proliferate in an appropriate
environment. The shorter answer is no one knows how this process
occurs, but whether it occurs in an efficient way is, I think, also a
matter of debate.
DR. FOSTER: But just to follow, I mean I saw a picture in
PNAS where you put a green fluorescent protein on and you were tracking
infiltrating cells from a glial blastoma and there were a lot of these
neurogenic stem cells that got into the lesion.
PROFESSOR JESSELL: Yes.
DR. FOSTER: Not only in the mass but moving in there and
honing in on it. So maybe you're saying—
PROFESSOR JESSELL: I'm completely receptive
to the idea that perhaps under conditions where in a tumor
the blood brain barrier has broken down, one of the things
the tumor does is produce attractants that then guide cells.
I think there is likely to be that process.
CHAIRMAN KASS: Dr. Carson.
DR. CARSON: Yes, early on, you were discussing the
periventricular glial cells which divide and then give rise to
neurons. There's always left behind a glial cell. Now is it
possible later on to provoke that residual glial cell to differentiate?
PROFESSOR JESSELL: Yes, this relates to why most of the
adult nervous system doesn't actually produce neurons, only these
two little epicenters. So does that mean that the precursor cells
simply don't exist in those other regions or whether they exist and
they're quiescent and something needs to happen in order as you say
to provoke them?
There's a lot of evidence, for example, in the spinal
cord, one of the areas that is not noted for neuronal production. If
you damage the spinal cord, ependymal cells around the central canal
will start to proliferate and start to produce glial cells. So there
clearly are environmental stimuli or trauma that can kick these cells
What they can't do still even under those conditions is
produce neurons. They seem to produce glial cells. So is there a
single gene? As we saw there are single genes that produce neurons.
Is there just one gene missing from those cells that impairs their
ability to produce neurons? These are things that I think will emerge
over the next five years as many people are looking at this as now some
of the molecular players in the normal developmental process can be
applied to the conditions of cell regeneration in an adult context.
CHAIRMAN KASS: Mike Gazzaniga.
DR. GAZZANIGA: Dr. Jessell, a wonderful talk. I wish my
mentor, Roger Sperry, could have been alive to hear your first section
of it and that beautiful molecular work. When one hears the sweep that
you gave today, sometimes people can misunderstand the extent to which
the people come to think of the brain as a set piece to the extent to
which it can be infinitely plastic and change. Plasticity is used in
this funny way. We all still are capable of learning Leon tells me.
So plasticity in that sense is going on all the time.
But plasticity in the infrastructure of the nervous system
aspect is probably not as much as we would like to think it is. So
when we hear these beautiful examples of Merznich and of Rusty Gage and
so forth, I would be interested in your opinion on a scale of the set
piece—I think those were your words—versus the changing at the
PROFESSOR JESSELL: Yes.
DR. GAZZANIGA: And as you go through maybe by decade, just
give us a sense of your feel for that.
PROFESSOR JESSELL: I think there's no region of the
nervous system in which the two extremes of a genetic predeterminism
and environment don't contribute. I think the question is what are
the relative contributions of those types of programs according to a
I tend to agree with you that there is a remarkable degree of
molecular genetic programing of connectivity. The more one understands
the more remarkable that observation is. In regions like the spinal
cord where motor commands are essential for processes like locomotion,
I think there is very compelling evidence that many basic features
of those sensory-motor integration processes can get wired up in
the absence of experience, in the absence of activity.
One of the early sets of experiments as Sperry did before
he worked on the visual system really demonstrated that that
essentially if you misconnect so that the sensory information coming
from an extensor muscle is now rerouted to a reflexor motor neuron, an
adult animal has a hard job in adapting to that surgically induced
misconnectivity. So what that says which I think was the basic thesis
of Sperry is that essentially there are strong molecular cues that
drive the specificity of circuitry. That will occur in the spinal
cord. It will occur in the cortex.
What I think we're seeing in the cortex for example but
probably in other regions is that the extreme view that in the adult
state all of those connections are fixed at a functional and structural
level is beginning to be eroded a bit. But the real challenge I think
is to work out to what extent the environmental influence what are the
constraints achieved by these early molecular programs on which
environment can work.
Now all of these experiential influences have to have a
molecular basis. This is not some mystery. So presumably environment
and activity is changing connectivity through a molecular program. If
we knew more effectively the nature of that molecular program—what
does the firing of an action potential in the neuron really do
biochemically to that cell, what molecules change—then we will be
able to integrate more effectively the plasticity environment together
with these molecular programs. To me that's one of the great
things to emerge from understanding the molecular biology of
development. It allows you to perhaps demystify some of the
environmental influences that clearly do exist.
CHAIRMAN KASS: Janet, please.
DR. ROWLEY: Well we spoke about this earlier in our
general discussion and the release of this report and the one issue
that was not touched on directly is the whole issue of cloning for
therapeutic uses. I would be interested in your opinion on how you
think embryonic stem cells for example could be used therapeutically
either to deal with those problems of the central nervous system or of
course for spinal regeneration. The second part of that is what kind
of research is needed, what kind of support for that research is needed
to see whether embryonic stem cells do have a potential in dealing with
these very serious problems.
PROFESSOR JESSELL: So this is something that in a slightly
different context we in the lab experimentally got very interested
in because what we do on a day-to-day basis is work on spinal cord
organization and development and an important set of neurons there
are motor-neurons which really mediate all the central nervous system
control of action and movement. There is a reasonably good understanding
of the normal developmental processes that take a naive progenitor
cell and convert that to a motor neuron.
So one of the things we asked is if we really understand
that process as it occurs in the normal embryo, can we then apply that
information in the context of other precursor cells like embryonic
stem cells and apply the right embryonic signals in the right order
and the right time and the right concentration and simply ask the
question of whether you can now convert an embryonic totipotent stem
cell and can drive that to a motor neuron using normal developmental
signals? Rather surprisingly that turns out to be quite easy to do.
So the same signals that operate in the normal embryo will operate in
the context of an ES cell such that you can produce fully
differentiated motor neurons from embryonic stem cells.
One of the things that I think development has taught is
how to manipulate other classes of progenitor cells along defined
pathways. That raises all of the questions that you mentioned about
what use is that going to be in regenerative medicine. It may be that
the motor neuron is not the ideal neuron in which to test this because
of the details of circuitry that are necessary.
So we come back to this question of if you put these cells
back in, how are they going to find their right targets in a very
different adult environment. But in some diseases, in demyelinating
disorders where one is trying to reintroduce oligodendrocytes or in
Parkinson's disease where there is almost proof of principle that
if you can put back dopaminogic neurons, you can ameliorate their motor
If you could make infinite numbers of purified dopamine, mid-brain
dopamine neurons, with that be an interesting route to self-therapy
in that particular neuro-degenerative disorder. I think all of
those issues are soluble now. What I think we've learned that
molecular biology has taught us how to turn embryonic stem cells
let alone the issue of adult progenitor cells.
But I think embryonic stem cells I think can be converted
to any class of central nervous system cell that one now is interested
in on the basis of the normal developmental program. To what extent
that information is useful in a clinical context I think will very much
depend on which disease one is thinking about. Somewhere it won't
be useful and there is somewhere where I think it's promising.
But the technology just from the point of view of cell
differentiation I would say exists today. So if one wanted to generate
one class of CNS cell, I think there are good ways now of thinking
about how to do that.
DR. ROWLEY: Then I ask a second part. What's needed
to move this field along?
PROFESSOR JESSELL: Yes. Much of the work that is at an
experimental stage has been done on mouse embryonic stem cells.
Mouse cells, ES cells, are remarkably constant from cell line to
cell line. The first thing that is needed is to ask whether the
developmental potential of human embryonic stem cells mimics or
reflects that in the mouse. I think what we know at the moment
is that many of the existing human ES cells, until Melton's
recent studies, have shown a remarkable variability in their properties
in differentiation along neuro-pathways, a much greater diversity
of properties than would be predicted simply from the mouse experiments.
One of the virtues of the report from Melton and his
collaborators in generating new cell lines is that many of these cell
lines now are going to increase the probability that some of them will
behave like their mouse counterparts. We have actually been working
together with the Melton group to extend some of the work on mouse
embryonic stem cells to ask which of those human lines that Melton has
generated behave most closely to their mouse counterparts. That's
a first step.
DR. ROWLEY: But then this brings the point which some of
us have again dealt with tangentially that these are not cell lines
that you can study with Federal funding.
PROFESSOR JESSELL: No, that's right. There's a
DR. ROWLEY: So that one of the critical things that's
needed is Federal funding for these new cell lines as they become
available to see whether or not they are useful.
PROFESSOR JESSELL: I would absolutely endorse that. They
are technical limitations.
DR. ROWLEY: And have you tried any adult stem cell lines
to see whether they too can produce functional neurons?
PROFESSOR JESSELL: Yes. So using the mouse
embryonic stem cell as a positive control, that is we can now turn
those cells into motor neurons at will with the addition of two
chemical factors. You are now in a position to ask whether adult
progenitor cells from the nervous system can recapitulate the properties
of the mouse embryonic stem cell as we currently understand how
to do that. If you do then adult neuro-progenitor cells will not
generate motor neurons under the conditions that the mouse embryonic
stem cells do.
What that tells us is there are some constraints on adult progenitor
cells. It doesn't mean it can't happen in the future.
It just means as of today I think the developmental repertoire of
an adult neuro-progenitor cell is very much more limited than its
embryonic counterpart. Just in a practical sense what you can do
with embryonic stem cells today in the context of neutral pathways
of differentiation far exceeds what can be achieved with adult neuro-progenitor
CHAIRMAN KASS: Could I ask before? We're going to
have to draw to a close fairly soon, but stepping back from some
of the particular phenomena that you've described and looking
at their possible human-social-education significance because we'll
be talking about this later on, and the question is exciting and
wonderful though this is scientific matter. If one wanted to think
about the possible human implications of this over the next decade
or so—I know you're not a prophet, you are a scientist—but
the question is what are the one or two areas or questions that
you would like us to keep our eye on when we think of the significance
One thing I gather has to do with the knowledge of some of
these horrible behavioral and mental disorders and the capacity to be
able to learn some of their sources and perhaps ultimately to
intervene. The other vaguer thing when Michael Sandel talks about
Mozart and the like and there's all kinds of faddishness out there
with respect to taking advantage of this alleged early environmental
stimulation to enhance the pre natal capacities, could you say again
along those lines and have we missed or did I miss something, some
other areas of significance?
PROFESSOR JESSELL: To me the greatest challenge is that
the very few, relevant interesting human behaviors, do we have any idea
about the principles of circuitry that underlie those behaviors? We
don't yet know. We have through imaging methodologies, through
other methods of intervention, we have a sketchy idea of some regions
of the brain that are more involved in learning and memory, mood
disorders. But the nature of the circuitry and the ability to
intervene in that circuitry and relate that to important forms of
behavior, I think is still at a very, very primitive state.
So one of the things that I haven't emphasized but I
think at a practical level is going to have important consequences,
both experimentally and in terms of studies of human behavior, is what
molecular biology of circuit assembly has given one so far are a large
number of genes that show that neurons that behave differently are
molecularly distinct. The advantage of that is that certainly in
experimental animals that is going to give you an unprecedented way of
manipulating the circuit on the basis of a neuron by neuron change
which hasn't been possible with conventional anatomy and
So for example if we knew in some region of the cortex a
gene that defined one very small subset of functionally coherent
neurons, how do you get at those neurons and how do you tell what their
contribution to circuit and behavior is at the moment? Through the
gene what we can now do as a field is introduce genetically encoded
proteins which allow you to manipulate that set of neurons in a
coherent way. For example you can introduce proteins that allow you
selectively and conditionally to take those neurons out of the circuit
and look the consequences for behavior. Or you can introduce sensors
that allow you to selectively activate those neurons and leave all of
the other neurons intact and look at the consequence of that particular
micro circuit for a given behavior.
So what I think will emerge from this is a much clearer
understanding of what behavior in any context really means in terms of
the details of the circuit. What are the core elements of the circuit
that contribute to that behavior? If one knew that, then I think the
diversity of range of human behaviors that one sees in the normal
population together with pathological behaviors one can start now to
analyze that from the level of single neuron or dysfunctions. What is
the relevant aspect of circuit that we're trying to look at?
I think, and Michael will have thoughts on this, my feeling
is at the moment is that we simply don't know enough about the
basic circuitry that underlies many of these interesting behaviors even
to know how to approach the problem. What I would hope is that link
between circuit and behavior becomes consolidated over the next ten
CHAIRMAN KASS: Thank you. Look we are 12:50 p.m. We have guests
coming at 2:00 p.m. I don't know how quickly people will serve
lunch where we're going. If Dr. Jessell might be willing to
simply standby for people who didn't get a chance to ask their
questions, I fear that if I don't discharge you now I won't
see you back here before 2:30 p.m. and that's not permitted.
So, Dr. Jessell, thank you for an enormously interesting and stimulating
presentation. It's a massive amount of stuff to present in
a kind of coherent way. I learned a great deal and I trust my colleagues
did too. Thank you and we'll reconvene at 2:00 p.m.
(Whereupon, at 12:48 p.m., the
above-entitled matter recessed to reconvene at 2:03 p.m. the
SESSION 3: NEUROSCIENCE,
BRAIN, AND BEHAVIOR II: EMOTIONAL AND COGNITIVE DEVELOPMENT
CHAIRMAN KASS: This afternoon's session, the first of
two, is titled "Neuroscience, Brain, and Behavior II: Emotional
and Cognitive Development in Children." And I've been asked
to say at least a sentence or two about, well, to be blunt, what's
going on here. This will not be long, and we'll have more to say
about what's going on here in the last session when we're
talking amongst ourselves, but I remind everybody that the purpose of
today's session agreed to last time was that before we took up and
searched for various ethical or social or philosophical issues raised
by advances in neuroscience and psychology, we ought to learn some of
the basic facts.
And the purpose of these discussions is to lay the
groundwork for anything further that we would do. The morning was on
the neuroscience. This afternoon is on the side of psychology.
There are no axes here, and there are no agendas, other
than getting us informed about the current state of knowledge about the
developing brain and the developing mind and behavior of children. So
if anybody is impatient, just soak up this knowledge. It's
The relation of the brain and the mind, of the activities
of molecules and synapses to mentation, never mind consciousness,
is, as everybody knows, a venerable question, a deep philosophical
issue that has occupied and vexed and challenged the best
minds since classical antiquity, and one simply has to mention
the names of Lucretius and Aristotle to show you how old these
controversies are. There are idealists; there are dualists;
there are compatiblists; there are epiphenomenalists.
Yet even as those sort of prize questions continue to be
discussed and debated, even people who are committed to fully
neurochemical and mechanistic account of all mental and behavioral
activity recognize the prime importance of studying the mental and
behavioral phenomena in their own right and on their own level, leaving
for later any attempts to connect the domains of psychology, the study
of the psyche, and the domain of neuroscience, the science of the
So with no prejudice regarding this deferred questions about the
relation of mind and behavior to the brain, we also want to
know not only about the neural development, normal development
of the brain and nervous system in children, but the normal
and also abnormal development in all of its variations of
the emotional and temperamental side of human development,
and of the cognitive capacities and activities of children,
and that is the theme for this afternoon's discussion,
and we're very fortunate to have two colleagues from Harvard's
Department of Psychology, Jerome Kagan, who is the Daniel
and Amy Starch Research Professor of Psychology at Harvard
University, and Elizabeth Spelke, who is Professor of Psychology,
also at Harvard University.
Dr. Kagan is going to speak about the temperament and
affective side, and Professor Spelke will speak about the cognitive
side, and I think the procedure is we will let each of them make their
presentations, perhaps with small questions of clarification after each
talk, and then the general discussion will follow.
Thank you both very much for coming down and being with us,
and we're delighted to have you here and look forward to the
Professor Kagan, would you like to start?
PROFESSOR KAGAN: Yes. Can you hear?
Thank you very much for inviting me, and let me also follow
Professor Jessell's suggestion that interrupt me if there
are any questions that you have during the presentation.
And I promise to hold it to 40 minutes, ten of three, so
that you can hear Dr. Spelke and have time for discussion.
Unlike the area you heard this morning, the growth of the brain,
which is, you know, mid-volume, the systematic work on human temperament
is about 50 years old. Since American psychology was committed
to a behaviorism that did not want to acknowledge biology, and although
there have been many essays going back to Hippocrates on temperament,
there is no empirical work.
So this is a field that is in Chapter 1, and therefore, we
can't show off the wonderful findings you heard this morning, but
we can give you a scaffolding.
Also, you should appreciate that in biology when a speaker
says "dendrite," everybody knows what he means. But when you
get to psychological concepts, people have different understandings,
and so I will try to give you the understanding that I'm using.
Remember the meaning of words, as Virginia Wolf said, is a function of
how they're used.
So the concept of temperament as it is used today in the
Western world means variation within humans in mood and behavior that
is biologically based. My own view is that it should be restricted to
inherited variation, but there are those who say any variation, even
variation caused prenatally.
Now, the analogy would be we talk about breed differences
in dogs. So some people like Rhodesian ridgebacks. Some people like
cocker spaniels. They belong to the same species. Their behaviors are
different, and we say those are breed differences.
When we talk about humans, that is the domain we're
talking about, but we use the word "temperament." My own
view is that most of the temperamental variation—one should never say
"all" in the life sciences—that most of the temperamental
variation will be due to inherited differences in neurochemistry.
There are over 150 molecules discovered. Many more may be discovered.
We all have the same molecules, but we differ in their concentrations,
and we differ in the density receptors, those proteins that sit on the
neurons. How dense are those receptors.
And we differ in the distribution of those receptors.
Thomas Insel, who now is the Director of NIMH, provides us with a
perfect example of what we mean by a neurochemical variation that
causes a big difference in behavior. So let me use it, and it will
help you understand the work on humans.
The vole is a very small rodent. It looks like a mouse.
Now, there's one strain of voles called prairie voles. They pair
bond. Once the male and female mate for six hours they will never mate
again with anyone else.
The montane vole that shares 99.99 percent of its genes
with the prairie vole doesn't pair bond. Now, that is a dramatic
difference in behavior, and Insel in 20 years of really elegant
research finds that the main cause of that difference is a change.
Remember a gene is a strip of DNA, but in front of each
gene is an area called the promoter region which governs the DNA.
Well, in the promoter region for two molecules, one is called
vasopressin and the other is called oxytocin, secreted during sexual
intercourse incidentally, both of these molecules; that that explains
So tiny, tiny genetic differences, not even in the DNA, but
in the promoter region for the DNA.
Now, I wish I could tell a story. Here are some of the
molecules, and remember there are over 150. At the moment they look
relevant. So children could be born with differences in opioid
concentrations or the receptors for opioids.
For example, right here in our neck is the structure called
the medulla. All pain, information from your heart and gut come up
through your body, and they have to pass through that gateway.
Well, supposed some individual was born with a light set of
receptors for opioids. Then they would experience pain and muscle
strain more easily than others.
GABA is an inhibitory molecule prevalent throughout the
entire brain and its job is to mute excitability. I'm going to say
in a moment that some infants are very irritable, extremely irritable.
It looks like a temperamental trait that expresses itself in certain
behaviors later in life.
It could be that what these children inherit, these very
irritable infants is a failure, a compromised function in GABA.
Dopamine is a powerful molecule. Every time any one of us
anticipate a trip, a holiday, a good meal tonight at 6:30, dopamine
pours out of our central nervous system. When a rat is about to get
food it wants, it pours out dopamine from its source in the brain.
Now, individuals, and it is believed by many that
there's a subtle surge of pleasure when one is looking forward to
seeing Rome for the first time and you're there. People differ in
their hedonic tone, in the amount of pleasure they take from
experience. It is not beyond reason that someone some day will find
that dopamine is playing a role.
Notice there's no determinism here. I'm going to
use words like "enable," "determine a role,"
Norepinephrine is a very important molecule. If you're
listening hard for a signal that your wife is coming home because
it's midnight. Norepinephrine acts on sensory neurons so that you
hear the signal you're interested in and not the noise or when
you're trying to hear a conversation several feet away. So
children are extremely vigilant to change, any subtle change, and some
children seem oblivious. Perhaps norepinephrine makes a contribution
And finally, just to have a flavor for these, corticotropin
releasing hormone is often secreted but not always when one is under
stress, and I'm sure most of you know that all of us when we're
under stress secrete a small hormone called cortisol from our adrenal
cortex, and variation in corticotropin releasing hormone could play a
Now, I wish we could go to a book and look up everything
we've learned about neurochemistry and now talk about human
temperaments. One day, but not today.
So those of us who study temperaments must begin with
behavior. That would be like medicine 250 years ago when one knew
nothing about what's happening in the immune system, and so the
patient tells you, "I have an ache in my body. I itch in my
arm," and so on. You go to the surface, and one day, of course,
we will tie together the behavior with the biology.
Now, many psychologists have been studying the
temperamental traits, and here are four that look like they might be
temperamental, that is, due to inherited variation in this
I mentioned irritability. Some infants are extremely
irritable, and the data indicate that that persisted the first year.
Now, you stop being extremely irritable when you're one and two
years of age, but investigators who have followed such infants find
that they are different at five, six, and seven years of age. Some
children are very active and show very high levels of muscle tension,
and we'll be talking about that in a moment.
Believe it or not, in the first six months some infants
smile a lot, and you'll see in about ten minutes I regard this as a
very powerful temperamental trait in humans. Children who smile a lot
in the first six months spontaneously tend to preserve a more sanguine
view of life through adolescence. Some infants don't smile at
all. As a matter of fact, in the laboratory they'll show a frown
on their face, and they tend to be more pessimistic children later in
Now, in order to concretize this discussion, let's tell
two stories. I'm going to tell you one story. It's the story
that I've been writing for 25 years, but it only reflects two
temperaments of the many. There are going to be thousands of
If there are 150 molecules and they vary in their
concentration and receptor density, remember from your algebra how many
combinations of 150 things you can have. There are going to be
millions of temperaments, and even if half were not functional,
you're going to have a very large number, some being very rare like
the Unabomber or Mozart, and some more common.
I'm going to talk about two common temperaments only
because the work on them is more extensive than others, and they're
relatively frequent, but not that they are necessarily the most
important temperaments, and it has to do with reaction to
In every vertebrate species, within every vertebrate
species, fish, birds, cats, mice, monkeys, and of course, humans, there
are some members that react to novelty and unfamiliarity by become
immobile if you're an animal, freezing if you're a rat, not
exploring an unfamiliar area if you're a mouse or if you're a
child, closing down and exploring the situation before you assimilate
it and move forward.
And other children are just the opposite. Now, in animals,
this is extremely heritable. You can breed it. You can breed quail,
rats, mice, and Steve Suomi of NIH believes even breed monkeys so that
after 20 generations you have either very timid or very bold monkeys,
mice or rats.
Now, it is believed by the work of many scientists that
deserve a great deal of credit, it looks like the amygdala, which is a
small structure right in back of your temporal lobe, tiny, shape of an
almond. It's very important because whenever you present novel
stimuli to any animal and you record from neurons in the amygdala,
those neurons respond.
And so if you presented a novel event to a monkey and you
had electrodes down the amygdala, it would respond, but if you kept on
presenting the stimulus, the neurons would stop responding. The
amygdala response is a novelty, and you can see why this is important.
You're a monkey out in the savannah, and you're
munching your bananas, and suddenly an odd sound occurs. The amygdala
fire, makes you alert, and then you decide whether you're going to
flee or it's an unimportant event and you keep on eating your
Now, I have been interested for many years in timid versus
bold children, and so to abbreviate ten or 15 years of work, we decided
that perhaps these were temperamental traits traceable to infancy, and
so we began a study of 500 healthy, middle class, four month old
Now, why did I restrict it? Because if you want to study
temperament, you have to eliminate all of the other causes of possible
timidity: a mother took drugs during her pregnancy; drank too much;
smoked cigarettes; drank coffee. And so you want mothers who cared
about their pregnancy and gave birth to healthy babies at term.
That means that if one did the study I'm about to
describe on infants born to compromised pregnancies we might get
different results. Okay? So these are healthy babies born at term.
Now, the reason why the amygdala is important is that if
you stimulate the amygdala of a cat or a monkey, you get limb movements
and you get distress cries, and of course, human infants will display
those two responses.
So here is the central idea behind the work. This is a
schematic of the amygdala. Vision audition and touch come into this
area of the amygdala, send their information up to this nucleus, and
then out to the body to produce tension, immobility, a rise in heart
rate, a rise in blood pressure or other biological consequences.
Assumption: if some infants were born with a chemistry
unknown at the moment that rendered the amygdala excitable to
unfamiliar events, then they should show a lot of motor activity and
crying when you present these unfamiliar events. If you were born with
a different chemistry, then you should show low motor activity and not
be very distressed, and we call those infants high and low reactive.
So after testing 500 infants by showing them unfamiliar
mobiles of different colored elements moving in front of them,
listening to speech on a tape with sentences like, "Hello, baby.
How are you today. Thank you very much for coming," or presenting
a cotton swab dipped in butyl alcohol to their nostril, olfactory,
auditory, visual, what you see is that 20 percent of the babies are
very different from all other babies. They begin to thrash. They
arch their backs. They become very aroused motorically and cry. They
should have a more excitable amygdala.
Forty percent, twice as much, are just the opposite. They
don't move. They lie there. They move an arm. They don't
Now we call the first group high reactive and the second
group low reactive, and now briefly I'm going to show you what
happens if you follow these infants through 11 years of age. Okay?
So you bring these infants back at 14 and 21 months for two
hours with their mother and they encounter unfamiliar events. Nothing
threatening, no snakes, no mice, just people they don't know, a
clown, people dressed in clown costumes, robots that move, novel events
that are not obviously dangerous.
Some children do not become very frightened. Some cry and
clutch their mother. I didn't bring my laser so if you follow me,
you see the high reactives are in the light color, the low reactives in
the dark purple. So at 14 months those who are high reactive at four
months were more fearful. At 21 months they were more fearful.
At seven and a half years the IRB of the university, in
order to make children cry, you have to do things that are unethical.
So we don't do that.
Now, with age what happens is that these traits become
internalized, and so rather than cry you begin to show the traits of
the introvert. You don't smile or talk easily with a stranger. So
if you're interviewed by an examiner for two hours, you talk less.
You see at seven and a half years you smile less.
You remember I said that smiling is very sensitive, and
based on observations of children and interviews with the mothers and
the teachers, you're more likely to have anxious symptoms. Now,
notice I'm not calling this child as having an anxiety disorder.
This is a child who doesn't want to sleep over at a friend's
house, needs night light on, asks their mother will they be kidnapped,
is their mother going to die. They're afraid of large dogs or
And you'll see that 45 percent of this group who are
high reactive had anxious symptoms. Remember only 20 percent of the
group was high reactive. So that's twice as many as you'd
expect. Only ten percent of low reactives had symptoms, while 40
percent of the sample. So that's much less than you would expect.
So these children are developing in a way that one would
anticipate, given the assumption about their amygdala. Okay?
Now, by the time they're 11 years of age, a lot of them
aren't shy anymore. What happens with increasing age is that you
get an increasing dissociation between your behavior, what you have
called your persona, and what's going on inside. Your grandmother
knew it as "don't judge a book by its cover."
But we believe that they retain their biology. So we have
to measure their biology, and I apologize for doing this quickly.
There are four measures that based on the research of many
scientists one would reasonably assume should characterize the high
reactive children at 11 years, but not the low reactives, and they
are: One is to have greater activation in the right hemisphere than
the left. For example, if you take a newborn baby and put lemon juice
on its tongue, you get right hemisphere activation. If you put sugar
water on its tongue, you left hemisphere activation.
Now, there are exceptions here, but as a rough rule the
right hemisphere is more active under states of uncertainty and
adversiveness, the left hemisphere under the complimentary state. So
we measured that using EEG.
Let's do the behavior first. When they come in at 11
years of age, we watch their behavior, and if we combine their behavior
at seven years and ten years of age, and here's the important
result, 40 percent of the children who had been high reactive made many
low comments. You see the turquoise blue bar on the left, and very low
smiles, 40 percent, while less than ten percent of the low reactives
While if you said who talked and smiled a great deal,
it's just the opposite. So, in other words, temperament constrains
what you will become. Forty percent are honest to their early
temperament, but only six or seven percent cross over. So that means
temperament doesn't determine what you will be, but its power is to
prevent a high reactive infant from becoming an extremely social,
exuberant child, while a low reactive temperament constrains that child
from becoming an extremely timid and subdued child. We'll return
to this in a moment.
Now, here are the data on hemisphere activation. The high
reactives are in pink, and the low reactives in yellow, and on the left
side of the graph is showing right hemisphere activation, and on the
right side of the graph is left hemisphere activation. So follow the
pink line, and you'll see that 43 percent of the high reactives
showed greater right hemisphere activation, and as you move towards the
left fewer and fewer high reactives, while the yellow line, only 18
percent of low reactives were right hemisphere active and they moved
So there's the first prediction. AT 11 years of age,
you can do better than chance at predicting hemisphere activation at 11
years of age from what they were like at four months.
Now, the next measure is more direct. In the system for hearing,
when you hear any sound it goes through a series of ganglia, first
your basilar membrane in your ear. Then it goes through a series
of nuclei and ends up in the mid-brain in a structure called the
And if you present clicks to an infant or a child, if you
get a series of brain waves from those clicks, every infant in
Massachusetts is tested this way to insure that it can hear. Now,
notice pk V. That is the evoke potential from the inferior
colliculus. It occurs in about six milliseconds.
Now, here's why that's important. The amygdala,
our friendly amygdala, sends projections down to the colliculus, pk V,
but not to any other structure before it, and that means that if you
had an excitable amygdala, you should show a larger pk V, a larger wave
V than if you were a low reactive.
I hope that's clear. So the 11 year olds wore
earphones, and they heard clicks for 90 seconds, and sure enough, as we
expected, the children who had been high reactive at four months had
large wave forms, especially when the loudness was 70 decibels and you
were measuring it on the opposite side of where the information came
So there's our second prediction, and that one does
support the notion that high reactives have a more excitable amygdala.
The third, many scientists over the last 35 years have made
an important discovery. Whenever you're presented with a visual or
auditory event that surprises you, you have a very distinctive wave
form. If you were sitting in a laboratory with EEG electrodes on and
you heard the following, "Washington, D.C. is a vegetable,"
that on the word "vegetable," you would have a wave form like
But if you heard "Washington, D.C. is a city,"
there would be no wave formed. So whenever you're surprised by an
event you don't expect, you get a very distinctive wave form.
Now, remember what I said about high reactive infants.
They are very sensitive to unexpected events. So we then hope to see
that at 11 years of age, the high reactives would show larger, evoke
larger event related potentials as you saw in the last slide to scenes
that were totally unfamiliar.
Go to the far right where it says "invalid."
These are ecologically invalid scenes, none of which are dangerous.
For example, a baby's head on an animal's body or a car in
midair or a chair on one leg.
While for the frequent, if you go over to the far left
where it says "frequent," that's a fire hydrant being
shown 70 percent of 169 trials.
So there's our third prediction affirmed. Right
hemisphere activation, a larger wave V, and a large event related
potential to surprising scenes.
And the last measure, the amygdala sends projections to the
sympathetic nervous system, and therefore, one should show greater
sympathetic tone in the cardiovascular system, and we measured that in
several ways, and so the term sympathetic means that you have greater
priming of the circulatory vessels and the heart, while the vagal
system means you have less priming because it is mediated by the
parasympathetic system, and as you can see, about 65 percent of the
high reactives at age 11 were sympathetic compared with about 38
percent of the low reactives and the opposite for vagal tone.
Now, let's put it together. A temperamental bias
constrains what you will become. Let me skip that, and here is the
final line. About one in four high reactives and one in four low
reactives combined expected behavior with biology versus one of 20 who
That means that if outside that door there were 100 adults
and I said—they're 20 years old—I said they're high
reactive infants, every one of them. If I predict that they will not
be exuberant, bold, highly sociable 20 year olds who show right
hemisphere—they wouldn't show right hemisphere activation; they
wouldn't show a big wave V; they wouldn't show sympathetic
tone; I'm going to be right 95 percent of the time.
If you say they're going to be quiet introverts who
have high sympathetic tone in a large wave V, you'll be right 20
percent of the time.
And of course, the same thing shows for the environment.
If I say, "I have this beautiful girl born to nurturing parents in
a lovely suburb of Boston who went to good schools, she's 25 years
old. Tell me about her," you will be more correct if you what she
She's probably not a drug addict. She's probably
not a prostitute. She's probably not on welfare, but what else?
Who did she marry? What did she major in? What will she do? You have
And that's an important message which we have in
psychology, tend to think of the environment and biology as
deterministic, and we should begin to think of it rather as
constraining rather than deterministic.
Because of time, let me go to some of the implications
because I don't want to take much time from Professor Spelke. Here
are some implications.
Individuals with similar public profiles can differ in the
origins of those profiles. Current psychiatry, 99 percent of all you
read in the papers about the epidemiology of psychiatric illness is
based only on interviews. They never assess the biology of the person.
And so two people can say that they worry. They're
worried about the war or they're worried about terrorists, but one
person has an extreme emotional reaction, and once psychiatrists begin
to add not necessarily these measures, biological measures to the
interview, then you will see all of the prevalence figures for mental
illness change because right now they're based on one source of
Second, the ancients understood a temperamental bias does
not imply that will is impotent with respect to a behavior. Remember
the ancients said that temperaments control your mood. They don't
control your action.
So I can feel anxious, but I can control my tendency to
avoid. I can feel angry easily, but I can control my impulse to
strike, and so on. And so we're in a dangerous period because
biological determinism is so popular in having the public believe,
well, after all, if this is genetic, then why should I be held
responsible for my behavior.
The third implication will come in about 20 or 25 years
from now because there will be variation in temperaments across
reproductively isolated populations. When mutations occur and they
change the shape of your eyes, the color of your hair, whether
you're vulnerable to spina bifida or not, nature doesn't stop
there. Obviously the genes that separate reproductively isolated
populations are going to affect the neurochemistry, too, and so
we're going to discover in a quarter century that there are
temperamental differences among Asians, Africans, aborigines of
Australia, Europeans. No question about it.
Although the work is preliminary, it is pretty clear now
that Asian and European infants differ dramatically. There are three
studies: Daniel G. Freedman, Caudill, Michael Lewis, my own.
Asian infants tend to be very low arousal, whether they are born in
America or born in Beijing, while European infants are much more
active, more easily distressed, and those look like temperamental
differences, and I'm sure when we are less self-conscious—unfortunately we are—about ethnic differences, right now it's
focused unfortunately on school performance and IQ and that will
vanish, but there will be temperamental differences. I think that
the benevolent consequence of that is that we'll recognize that
every reproductively isolated group, as is true for humans, is true
for animals, has a special set of advantages and a special set of
disadvantages, and that's the way it goes, and that will be,
I think, beneficial.
But there will be differences in risk for particular moods
and psychological symptoms. There's an Asian psychiatrist in Los
Angeles who has written several papers that, for example, Asian
patients in Los Angeles require half the dose of Prozac or Valium than
Caucasian patients with exactly the same psychiatric diagnosis.
So we return to voles again. This research has just
begun. I must confess to you as I now stop that I'm surprised by
these results. I wouldn't have expected them.
When I was a graduate student, I was very hostile to the
role of biology in human affairs. I was convinced that most
of the variation among 20 year olds was a function of what
happened within the walls of their family, but I've been
dragged to this conclusion by their data, even though as I've
shown you the role of the environment is powerful for temperament
constrains rather than determines.
Thank you very much.
CHAIRMAN KASS: Let's agree to have just a couple of
minutes for questions of clarification, although the two papers I think
might be best discussed at the end.
Diana Schaub, Diana.
DR. SCHAUB: You spoke of ethnic and racial differences.
Are there sexual differences also? Do girls tend to be more high
reactive than boys?
PROFESSOR KAGAN: Right. Surprisingly, there's no
difference at four months. High reactive and low reactive infants,
it's equal on the sexes.
Now there's an interesting story. Under age seven or
eight more high reactive girls are timid, shy, introverted than boys.
But by adolescence, it has changed. Now, I think this may be—here's my hypothesis.
At 15, it's just the opposite, and I think it's
because girls in this culture are gentler with timid girls than boys
are. Boys are very cruel, and so at 15, which is the age we're
studying now, high reactive boys who have not lost their persona, they
are very shy, very frightened, very introverted.
Our girls are garrulous, have many friends, and my own
belief is that that's all environmental. It's because girls
are less cruel toward a girl who is initially timid in her personality.
But there is no difference at four months.
CHAIRMAN KASS: Jim Wilson.
PROFESSOR WILSON: Thank you very much, Jerry.
You said toward the end of your remarks, speaking, I think,
of adult populations, that psychiatrists should gather biological
evidence. What kind of biological evidence, and how do they gather it?
PROFESSOR KAGAN: I would say I think it would be very useful
if as part of the psychiatric examination, I'm thinking of
something that could be done in the office. You could easily gather
sympathetic and vagal tone, easily. Given the fact that many are
associated with the hospital, you could order an EEG and get right and
left hemisphere dominance, yeah, and I think that would help the
CHAIRMAN KASS: Other questions? Michael Sandel.
PROFESSOR SANDEL: This is a simple minded question, Jerry, but
what was the question that drew you to this? Were you trying to figure
out what makes some kids shy and some kids bold?
PROFESSOR KAGAN: No.
PROFESSOR SANDEL: What was the animating question for you?
PROFESSOR KAGAN: The animating question was this. My first
job was at the Fels Research Institute in Yellow Springs, Ohio, in the
campus of Antioch College. I inherited a corpus of data that has been
gathered since 1929, and Howard Moss and I studied the adults, and he
rated the children, and only one trait was stable from the first two
years of life to adulthood, and it was these two traits, but I
didn't understand it in 1957.
But I was thinking about it, but I resisted. Then Zowazo,
Richard Kiersley, and I were doing a study of the effect of day care.
Remember years ago, in 1978, the Congress was going to vote day care,
and we were certain day care was bad for infants. So we got an NIH
grant, and we began to study in the South End the role of day care on
But we needed political protection. Things were very bad
then if you remember, and so the Chinese Christian Church said,
"We'll protect you, but you must take Chinese American infants
from Boston's Chinatown."
So we had half Chinese American infants and there it was,
and that's when I saw that these children were temperamentally so
different. Then I remembered the Fels, and of course, I had been
studying children for 40 years, and I realized I was resisting the
notion of temperament. I was resisting it.
And my resistance collapsed, and that's why I did this.
CHAIRMAN KASS: Peter Lawler.
DR. LAWLER: You seem to have, as far as I can understand,
covered some of the wisdom of Machiavelli, right? Some people are
impetuous; some people are cautious. These are natural things. We
really can't change them very readily, and which is better sort of
depends upon circumstances, and the point of education is to rein in
the destructive aspects of one or the other.
But then the last page of the very fine chapter that you
gave us you said what we now have to do through education we will
eventually be able to do through pills. Do you really think this is
PROFESSOR KAGAN: Oh, no. I'm sorry. I hope you
didn't misinterpret the last page. This book says in our
technological culture both types have advantages. There's a line,
I think, in the chapter which says if we ask T.S. Eliot the day after
he won the Nobel prize, you know, you—if you read his biography, he
was a very inhibited child—you know, would you have wanted your
mother to give you medicine, he would have said no, because he
wouldn't have become a playwright.
We need people who like to work alone, bench scientists,
programmers, and of course, that's where our high reactives drift,
and we need statesmen and surgeons and trial lawyers, and I think the
account is balanced.
If I can tell an anecdote that Steve Suomi told me, on the
island of Cayo Santiago, which lies off Puerto Rico, there are 1,000
Rhesus monkeys. No one lives there, but graduate students code their
behaviors. They know which ones are timid, which bold.
And one spring, Steve—
PARTICIPANT: (Speaking from an unmiked
PROFESSOR KAGAN: Sorry? No, the monkeys. Sorry.
In one year two juvenile males died of starvation. They
were the timid ones. Because food is put out once a year, and they
wait, and if you wait too long, you die of starvation.
Two bold monkeys died because they attacked two large alpha males,
and so four males died, two from one temperament, two from
another, and the account is balanced.
We don't tell our mothers of high reactors that, you
know, this is a trait you should change. In an earlier study, one of
our most inhibited boys said to an examiner at nine or ten, to the
question what do you want to be, he said, "I want to be a
He paused, and he said, "I like being alone."
That boy is getting a Ph.D. in physics from Berkeley this year.
He's going to be a productive member of our society.
So in a society as diverse as ours, it is not obvious that
one of these temperamental types has advantages and you wish to change
DR. LAWLER: So although you try to be nonjudgmental here
at the end, you actually are quite judgmental on this. That is, nature
has given us a pretty good deal. We shouldn't mess with it that
PROFESSOR KAGAN: Yeah, I think in our society, which is mobile
and youth leave their homes and so many jobs require dealing with
strangers and risks with minimal uncertainty, at this historical
moment, not in colonial times, there probably is a slight advantage to
the low reactive, slight, yeah.
CHAIRMAN KASS: Let's just take one more, and then we
can hold the rest of the conversation. Gil, do you want something
PROFESSOR MEILAENDER: I think so.
You used the words "bold" and "timid"
with respect to temperament. Moralists in speaking about virtues
sometimes use words like "courageous" and
"cowardly." What would be the relationship do you think
between your words "bold" and "timid" and the
moralists talk about "courage" and "cowardice"?
PROFESSOR KAGAN: I'm glad you asked that. Very
different. When I use the word "bold" and "timid,"
I mean what is your initial reaction to a challenge or a novel event.
Is the initial tendency to psychologically freeze, encase it, or go
That has got nothing to do with defending your values, and
as a matter of fact, the interviews at age 15 are revealing that
it's the high reactives who are more likely to defend their
Let me end by reminding you of that wonderful paragraph in
Portrait of an Artist. Remember Stephen Daedalus is Joyce, who
is a frightened, timid boy, and remember his mother. He's talking
to a friend, and he says, "I'm not going to Easter mass. I
don't believe in it."
He says, "But your mother wants you to go."
And then he says, "No, I shall be a hypocrite."
He says, "So what? You don't believe. Go to
please your mother."
And Stephen says, "I can't."
That's often the reaction, so that in terms of
courageously defending your beliefs, I have the inkling—and I'll
stop—that those are the high reactives. They're often
ideologically more courageous.
CHAIRMAN KASS: Let's hold the rest of the discussion
until we have Dr. Spelke's presentation.
PROFESSOR SPELKE: While we're waiting for the PowerPoint
to come up, can I just ask if anyone has a laser? That would be
great. If not, I'll make do.
CHAIRMAN KASS: Do we have one or not?
PROFESSOR SPELKE: If not, it's okay. I can do without.
Thank you for inviting me today, My task is both exciting
and impossible. There's no way that in 40 minutes I'm going to
really be able to convey to you what we've been able to learn about
children's cognitive development, but I do want to try to talk
about three aspects of the work that has been going on.
First, I want to tell you a little bit about the methods that
have been developed over the last 50 years or so for addressing
questions that people have asked for 2,000-plus years about the
origins of our understanding of the world, the experiences of young
infants, the states of knowledge of infants and how our knowledge
grows and changes with development.
These questions are very old, but research strategies for
addressing them have really emerged in the last 50 years, and I want to
introduce you, in particular, to two research strategies that have been
important and will do so in talking about space perception.
Then I want to turn to some substantive topics and talk
about two core systems of knowledge that I think these strategies have
given us evidence for in young infants. One is a system for
representing and reasoning about the physical world, particularly
solid, manipulable objects, and the other a system for representing and
reasoning about people.
And then my final substantive topic, I want to turn from
the systems of knowledge that infants have to some central systems of
knowledge that they appear to lack and that children appear to
construct over the course of the preschool years from about age two to
And although there's many such interesting systems,
because of time limits I'll just give you one example and talk
about the construction of natural number concepts, and then if
there's time at the end and you'll permit me, I wanted to lay
out just a couple of themes that I thought might suggest questions that
you would want to consider in this group.
So beginning then with the origins of space perception, as I said,
this is a very old question, but until relatively recently, "recently"
being around the mid-1950s or so, there weren't systematic attempts
to answer it because there seemed to be this insurmountable obstacle.
In order to answer these questions, we needed to understand what
human infants experience about the world.
Yet human infants have extremely limited abilities to act
on the world, to communicate with other people, to convey to us what
their experience is. And that seemed to place a major obstacle in the
path of pursuing this research.
Well, I think the first serious progress in overcoming this
obstacle came about around the end of the 1950s through the work of
Eleanor J. Gibson and her collaborators, and the crucial research
strategy that she employed was a comparative strategy.
She started with incidental observations on newborn goats,
that if you took a goat just born and put it on a flat surface, it
would start walking around, but if instead you put it on a tiny stool,
it wouldn't move. It would freeze and not move off the stool, and
Gibson wondered what role visual information might be playing for the
goat in controlling this behavior.
So she designed the now-famous visual cliff. This is a simple
apparatus where there's a center board that you put an animal
on, and two plexiglass surfaces immediately below the center board.
So immediately below the center board on both sides are two surfaces
that will support the animal, which if the animal reaches out and
touches them, they'll feel that they're rigid surfaces of
However, on one side, she put—if I had a pointer, I would
point to the right there—she put a visual pattern directly below the
plexiglass. So the surface not only was solid. It also looked solid.
Whereas on the other side, she put that pattern much
further away. So it looked as if there was no surface of support
there, even though there was one, and what she found was that newborn
goats placed on the center board would readily go scampering off on the
visually shallow side and avoid the visually deep side.
Now, of course, this is useful to goats, since they live on
mountains and need not to fall off them, but this observation raised
the question, is this an ability that we'll only see in animals
living in those kinds of environments or will we see them more
And to address that, Gibson repeated the visual cliff
experiments on a wide range of different animals, including rats and
kittens and human infants.
The findings are easy to summarize. For any terrestrial
animal that she studied, at the point at which the animal becomes
capable of locomoting on its own, which is at birth for some animals;
it's after a few weeks or months of birth for other animals; for
human infants, it's about six to eight months after birth. At
whatever point an animal begins locomoting on its own, they would
locomote over the visually shallow side and avoid the deep side.
The next question Gibson asked then was: is each of these
abilities in different animals due to a distinct mechanism or, rather,
is there a single general mechanism for perceiving depth and using
depth to guide locomotion that evolved in some distant ancestor common
to all of these animals and, therefore, the same mechanism at work
To address that question, Gibson did a whole further series of
studies, which I don't have time to describe, looking
for each animal at the signature limits for cliff avoidance.
That is to say, the conditions under which they would succeed
in avoiding a visual cliff and the conditions under which
they would fail, in which she found across this range of animals
was common limits across the animals, providing evidence that
common mechanisms were at work in all of these animals.
Finally, a question arises. What about for those animals that don't
locomote at birth and that require some weeks or months of postnatal
experience before they start engaging in visually-guided locomotion?
What role does experience play for those animals?
Well, this is a question that one can't ethically ask
for human infants, but one can ask for other animals by doing
controlled rearing experiments, and Gibson did a whole series of
experiments where she reared rats or kittens in darkness or with
nonspecific visual stimulation or with specific experience with cliffs.
And to make a long story short, what she found was that in those
animals this ability developed independent of any specific learning
about the effects of cliffs. In some animals nonspecific visual
stimulation was necessary for the development, probably for the
reasons that Dr. Jessell talked about earlier today, but no animal
needed to learn to avoid the drop-off.
So the conclusion from all of these studies is that depth
perception is innate in the sense that it develops independently of
specific learning in mammals, including humans, given the evidence that
common mechanisms are at work across these animals.
Nevertheless, there's two general related limitations
to this line of work. It doesn't allow—when you study
systematic, coordinated behaviors that only emerge late in human
infancy, you don't have the possibility of studying the actual
development in humans of these abilities until those behaviors emerge.
And the second limitation, this comparative method works
great for studying the development of abilities that we share with
other animals. It's less clearly applicable to studying
developments that are uniquely human.
So let me introduce the second research strategy that has
been important for this field. There are a number of people
responsible for it, but I think one watershed set of studies were
provided by the psychologist Robert Fantz, again, in the late
'50s. He focused on the fact that human infants from the moment of
birth do engage in at least one highly systematic and controlled
behavior. They look around the world, and they will show systematic
tendencies to look at some things more than others.
So drawing on this observation, Fantz developed the
preferential looking method, which you see a picture of here. What you
have is a baby lying on its back. It's looking at two visual
displays side by side, and between the displays is a peep hole. Back
in the '50s you didn't have a video camera, I guess, to do
this, and a person looking through the peep hole and just judging which
of the two displays infants looked at.
And he found that down to newborns infants would show
systematic visual preferences under certain conditions, and two
particularly interesting ones. First, they would tend to look longer
at novel arrays. So if you presented an infant over a whole series of
trials with, say, two red circles on both sides of the peep hole, and
then after they had seen those for a while you presented one red circle
and one green square, the infants would tend to look longer at the new
display, showing that they were showing some form of memory and visual
discrimination, and I'll come back to that novelty preference
later. It's not incompatible with the novelty weariness when you
present an entirely new situation that babies show under other
The second finding was that infants looked longer at three
dimensional displays than at two dimensional displays, and that's
actually the study that's being pictured here. What a baby is
being shown is a sphere, three dimensional sphere on one side of the
peep hole and a flat disk on the other side, and the babies looked
reliably longer at the sphere.
Now, this may seem to show that babies perceive depth, but
actually it doesn't because there's two different accounts one
could give of that visual preference, as the psychologist Richard Held
pointed out some 20 years later.
One way to illustrate these two different accounts is to
consider some experiments that Held did himself. Now, these
experiments were looking, testing for the development of a certain kind
of depth perception, not the only kind, but the one whose neural
mechanisms Professor Jessell was talking about this morning, perception
of depth from stereopsis.
And for these studies, Held put stereoscopic goggles on
infants such that each of the two eyes was seeing a different display,
different pair of visual displays.
One of the displays that was projected to both eyes
projected exactly the same array to both eyes, and for an adult with
normal stereoscopic depth perception, that looks like an array of flat
The other display presented stripes that were two patterns
that were slightly offset with respect to each other, to the two eyes,
and when you put on stereoscopic goggles and look at that display, you
will see stripes arrayed in depth.
Now, the first thing that Held found was that at about four
months of age, between three and four months of age, infants start
looking longer at the display that we adults see as stripes arranged in
depth than at the display that we see as flat.
But Held pointed out there's two very different stories
you could tell here about this preference. On the one hand, maybe
infants are also seeing depth just like we do.
On the other hand, it's possible that when infants look
at the display on the right, they just see a pair of double images,
whereas when they look at the display on the left, they see a pair of
coincident imagines that fuse into a single imagine, and so a very
different experience could be underlying their preferential looking
relative to our depth perception. So how do you get around that
Well, what Held suggested, and this is the critical
research strategy that I think has been followed in most of the work
that has been done since this time looking at perceptual and cognitive
development, what he suggested relies on 100 years of work on the type
of physics of depth perception in adults, work that reveals that we
adults perceive depth from stereoscopic information only under a very
restricted and well defined set of conditions.
So, for example, in a display like this, we'll see
depth if the edges are slightly offset from each other, but not if
they're very far offset from each other. We'll perceive depth
if the edges are vertical, but not if they're horizontal.
We'll perceive depth if we look through the stereogram with the
glasses on, but not if we take the glasses of.
And so Held suggested we can look across this range of
conditions at when infants do and don't show the preference for the
display on the right.
And what he found was that infants' preferences lined up down
the line with adults' perception of depth. Infants preferred
the display on the right, starting at about four months under all
and only the conditions in which adults perceived depth. So that
common set of signature limits suggests that infants aren't
just responding to double images. Rather, they've got the same
mechanism that we have and it's working in the same way, giving
us reason to attribute to infants the same kind of experience of
a three-dimensional world at that point in development as we have
So to conclude this first section, what this work put together
suggests is an answer to a 2000 plus year long debate. The tendency
to look out into the world and see a stable array of surfaces at
a distance from ourselves and stable, coherent three-dimensional
arrangements appears to develop largely independently of experience.
We seem to be built to perceive space.
The mechanisms by which we do so are not unique to humans.
They're shared with other animals. And the mechanisms by which we
do so as adults have a long developmental history in us. We see the
same mechanisms at work in human infants. And these continuities,
ontogenetic and phylogenetic, provide a set of tools that we can use
for shedding light on infant's perception capacities and also on
some of their cognitive capacities.
So what I want to do now is use these tools and take you
very briefly through some of the highlight conclusions of research
looking at what infants understand about inanimate objects and what
they understand about people.
I'll be particularly fast in talking about objects
because this work is relatively older and some of it was in some of the
supporting materials that there circulated to all of you, but basically
starting as using Gibson's approach focusing on adaptive behaviors
on objects and particular in these studies the adaptive behavior would
be reaching out for objects and manipulating them and also studies
using Fantz's approach focusing on preferential looking and in
particular the tendency to look longer at novel events. These two
lines of studies have both been conducted to ask, what do infants see
when you present them with an array of objects. And they converge on
the same set of conclusions.
One conclusion is that infants have capacities that we also
have as adults, starting as young as about 2 months of age, maybe
younger, though. It's hard to do these studies when infants are
younger. Capacity is to take a continuous array of surfaces and break
it into units. And the boundary of those units generally coincide with
the boundaries that we take to be the objects, in a scene.
So, for example, if you present a baby with two objects
sitting on top of one another, one of which slides over the other but
remains in contact with it throughout that motion, present it until
babies are bored with it, and then reach out and lift up the top object
and either it moves by itself or the two objects move together, babies
look longer if the two move together, suggesting that even though the
objects were in contact throughout the time the babies were becoming
bored with them, they were nevertheless perceiving a boundary between
Other studies have asked whether babies are able to
interpolate parts of objects that are hidden from view. If you see an
object whose top and bottom are visible and its center is hidden behind
another object, can babies ever extrapolate that connection between the
two and see a connected object? And again the answer is they can, if
you bore them with a display like this, a rod moving together behind a
block, never enough for its center to come into view. They will be
relatively bored if you then take the block away and show them a
complete rod, suggesting that that's not new to them, that's
what they were seeing before and relatively more interested if you show
them a rod with a gap in the center.
Further studies have asked whether babies are able to
represent objects as continuing to exist when they move fully out of
view. And these studies show that they can, under certain conditions,
and that they keep track of objects that move in and out of view in
accord with the basic principle that objects are going to move on
spaciotempororally connected paths. They're not going to jump from
one place in time to another.
So, for example, the study of ours took four months old infants
looked just at the—I'll just describe the case on the right.
Four-month-old infants and presented within an array where there's
two screens, an object moves behind one screen. Then there's
a pause. And an object that looks just like it moves out into view
from behind the other screen.
Now, adults looking at that will infer that there's two
objects in that event behind the screen because one thing couldn't
move from far on the left to far on the right without traversing the
space between the two.
To see if babies perceive that, we again bore them with the
event I just described and then remove the screens and alternately show
them arrays with one versus two objects. They look longer when you
show only one, suggesting that they like us, perceived two objects in
And one last example, studies have asked whether babies are
able to make inferences about mechanical relationships between
objects. And in particular, if babies infer that objects will act on
each other when and only when they come into contact. This is one of
the earliest experiments that was done by, I think, an undergraduate at
the time. It may have been an undergraduate of Jerry's, William
Here's the events that he presented to infants.
There's a screen. There's an object that's partly hidden
behind the screen and another object that moves behind the screen, and
when it's fully out of view, the object that's initially half
hidden and stationary starts to move, okay. Now adults look at that
and infer that the first object hit the second and set it into motion.
But actually, the event is physically consistent both with that
possibility and with the second. The screen is big enough that the
first object could have stopped short of the second object, and it
could have started moving on its own.
So to see whether babies made the same inference as adults,
we bored with the top event, and when took the screen away and then
indeed they looked longer at the event where the first object stopped
short of the second, suggesting that they inferred that the two would
come into contact.
Well, putting all this work and other related work
together, I proposed and others have proposed that babies starting at
about two to four months have a system for building representations of
objects that accord with three general spaciotemporal constraints on
They build objects that are cohesive, that is, bodies that
are internally connected and move relative to one another, that are
spaciotemporally continuous, that is, that these are things that bodies
can't do. They move on connected paths, but they don't jump
from one place to another and their paths also don't intersect,
such that two things occupy the same space at the same time. And they
move when and only when they come into contact, there's no action
at a distance.
But interestingly, this is not to say that infants perceive
objects under all the conditions that adults do. My colleague Susan
Carey has discovered some interesting limits to infants' abilities
to perceive objects. If you present them with situations where
spaciotemporal information for properties like cohesiveness and
continuity do not dictate where the boundaries of objects are. For
example, you place a toy duck on top of a toy cup, presenting no
relative motion between the two, no motion at all in the scene,
infants' perception of the boundary of those objects is
Now recently there's been a lot of beautiful work, some
of it on the island of Cayo Santiago that Jerry was talking about
asking whether this same system of representation exists in nonhuman
primates and also asking whether the same system exists in adults. And
like the strategies of Gibson and Held, the way of asking whether the
same system exists is to ask do we see the same abilities and the same
limits. Well, to just simply give you the answer, since I don't
have time to take you through the studies, the answer appears to be yes
in both cases. This system exists in adult rhesus monkeys. It also
exists in human adults when you test us under conditions where
we're not able to use our specific knowledge about the world, our
language, other strategies that infants lack to track things through
time. We show the same patterns of success and failure as infants do.
Well, let me turn to the other core system that I wanted to
lay out for you. This, I think, is a system for reasoning about
persons, and there have been many signs from studies of infants over
the last 20 years or so that the system exists and is at least as
important for infants as the system for representing objects.
One source of evidence for this system comes from some studies
conducted by the psychologist John Morton and Mark Johnson with
newborn infants. They took brand new babies, put them on the lap
of an experimenter, and presented them with simple schematic oval-shaped
patterns, either a pattern representing a face or one of a number
of other kinds of displays. And when the baby was looking at the
pattern, they slowly moved it to the left or right, and the measure
was how far would the baby follow the pattern, how far could they
move it before the baby would lose interest, turn away, no longer
track it? And what they found was that babies would track for the
face pattern at birth reliably longer than for the patterns that
clearly were not face-like and not reliably, but somewhat longer
when they tracked a simplified face pattern as well. And this study
and others suggests initial sensitivity to the structure of the
Here's another ability that comes in by about two to
three months of age from studies by Bruce Hood. In these studies,
infants view the face of a person on a computer screen looking straight
at them and then, I don't know if you can see it up here, but the
person's eyes turn either to the left or to the right, and right
after that the person disappears and an object appears either on the
left or on the right. Now no matter which side the object appears on,
the babies turn to look at it. But when Hood measured how fast babies
turned to look at it, it turned out that they turned to look to the
object faster if the person's eyes had—if it appeared on the same
side where the person's eyes had turned than if it had appeared on
the opposite side.
So from about two to three months of age, babies are
sensitive to human gaze, and they're following the gaze of a person
who's looking straight at them to an object that's facilitating
their attention to other objects.
Well, what about people's actions? Do babies form any
sensible representations of other people's actions? Well, this is
something that psychologist Amanda Woodward has been studying for the
last five years or so through some simple ingenious preferential
looking experiments. In these experiments, she shows a baby two
objects and a person whose hand reaches repeatedly for one of the two
objects, so for example, for a given baby it might be the ball. After
the baby has gotten bored with looking at this, she then switches the
positions of the two objects and has the hand alternately reach to one
versus the other.
Here's the reason for doing the experiment. The question
is, when the baby sees the person reach for an object how do they
encode what the person is doing? Do they think the person is just
like an inanimate object that would move from one position in space
to another position in space or do they encode the action as goal-directed,
directed to the goal, in this case reaching for the ball? Well,
if they encoded the action as simply a movement through space, then
this should be the event that's most similar to it. But if
they encoded it as an action directed at a goal, then when the two
objects move, it's the new action to the new position to the
old goal that should be seen as more similar, and infants' looking
time was consistent with that second possibility. Okay? Infants
looked longer when the goal changed than when the physical trajectory
of the action changed.
PROFESSOR SANDEL: Could I just ask you, the test, though, is
PROFESSOR SPELKE: Right.
PROFESSOR SANDEL: How do you know what that means? How do you
know whether they're looking longer because they're making
sense of it or they're looking longer because it doesn't make
PROFESSOR SPELKE: Okay, in all of these studies, the pattern
of data internal to the study answers that question, okay? So for
example, you can have conditions in which you don't change the
positions of the objects. Right, and so if they're looking longer
to something that's familiar or sensible, they look longer to the
old motion than to the new, but that's not what they do. Does that
So I mean this is a situation that pits two kinds of
novelty against each other and when we see they look longer to this,
we're assuming they're going to look longer to novelty.
PROFESSOR SANDEL: That's my question. Why do you assume
that looking longer corresponds to novel—the perception of novelty?
PROFESSOR SPELKE: Right, because you can also do studies where
instead of pitting two kinds of novelty against each other, you can pit
an event which by any description is more novel against an event which
by any description is more familiar. So suppose, for example, instead
of switching the positions of these two objects, we just left them
where they were, let the babies get bored with one and then alternately
show reaching to the old one versus reaching to the new. Infants will
look longer at the new one, and so that's suggesting that in this
situation when they're bored, they will tend to prefer the more
novel event. Did that make sense?
PROFESSOR SANDEL: I thought the question—
PROFESSOR SPELKE: Let me—
PROFESSOR SANDEL: Please, so ahead.
PROFESSOR SPELKE: Let me keep going because I think in
principle that is a real concern and in practice the pattern of results
across the studies addresses it.
The one last thing I want to tell you about the Woodward studies
is that this effect is specific to people. When she's repeated
these experiments with inanimate objects moving towards—and the
inanimate object she used was superficially in some ways similar
to a human hand and arm. It was a stick with a sponge like deformable
thing on the end of it and she bores babies with the stick moving
to the ball and then switches the positions of the two objects.
She does not get a preference for moving to the same goal, suggesting
that this propensity to understand actions as goal-directed is applied
to people in infants of this age and I should have said these are
five-month old infants. It's not applied to inanimate objects.
Finally, there are other studies, infant sensitivity to
human actions, that show that babies are sensitive to relationships
between what they themselves do and what other people do.
The most famous studies, also were very controversial for
a long time, were conducted by Andy Meltzoff some 25 years
ago and showed that when, for example, he sticks out his tongue
at an infant, infants will reliably not really stick out their
tongue in kind, but act in a way that a blind observer looking
at it would judge to be more like sticking out your tongue
than like other events that the model engaged in.
We now know after many years of controversy that this
ability in newborn infants is extremely limited, but it is real and it
leads to much more dramatic abilities to attend to the actions of other
people and reproduce their actions on objects later in infancy.
I have just one example here to share with you. This is
also from a study that Meltzoff conducted with much older infants.
Starting at about nine months of age, if an infant views a person
acting in a particular way on an object and then that object is
presented to the infant, the infant will tend, if possible, to
reproduce the action that they saw the person perform. In this study,
which is with infants that are somewhat older, they're about 14
months. Meltzoff went a step further and asked what will happen if an
infant sees a person attempting to do something but failing, and in
this study the person is attempting to take this little barbell and
pull it apart and failing to pull it apart. What he found was that
when he then gives the barbell to the infants they grab it and pull it
apart. And again, this is specific to people when they see the very
same series of motions, but it's a machine that's doing the
actions, they don't show that effect.
Okay, so these are all ways in which infants seem to be
able to make sense of the actions of other people. But we can ask, do
infants also apply their understanding of inanimate objects to other
people? Do they expect that people will interact on contact, that
people will exist and move continuously. And some experiments have
begun to ask this. In particular, Woodward did a series of studies
where she took up the old experiment by Bill Ball showing that babies
infer that two inanimate objects that move in succession come into
contact and asked, will they make the same inference for people? So
for this study she presented infants with videotaped events of real
people or real large complicated inanimate objects, things like potted
plants and high chairs, not the objects that I've diagrammed there,
conducting the same experiment that I described earlier.
What she found is that as in the previous experiments, when
the objects were inanimate, infants inferred that when two objects
moved in succession, they came into contact, but when the objects were
people, they did not. Okay? No inference that the first person
slammed into the second to set them into motion.
Finally, very recent set of studies being conducted at Yale
in the lab of Paul Bloom have asked whether infants infer that
people's motion is subject to continuity. And here they took our
method for studying continuity that I already described to you, two
screens and an object that moves behind one and then another object
that appears behind the other and they found, like us, that when the
objects are inanimate infants infer that if there's been
discontinuous motion there must have been two objects. Interestingly
though, they don't infer that in the case of people, even though
it's true, right? A person can't move from the first place to
the second without passing through the space in between, but infants
don't infer that people's behavior is subject to that
So to summarize what I've told you about infants' understanding
of inanimate object motion and human action, I think we see evidence
here for two quite distinct systems of knowledge. In the case of
inanimate objects, infants reason about object motion in accord
with a principle of no action at a distance, contact mechanics,
if you will. They infer that such objects are not goal-directed.
They don't show goal-directed inferences in the Woodward kinds
In the case of people, you see just the reverse. People are predicted
to act in relation to goals and not in relation to proximal mechanical
Similarly, tracing people over time may involve making
inferences about their intentionality. Certainly babies seem to be
sensitive to intentionality, and it doesn't involve making
inferences about continuity, whereas for inanimate objects the reverse
would seem to be the case.
So it looks like we have two distinct systems here. Now I've
raised the question that I can't, unfortunately, answer
about whether these systems show continuity over phylogeny
and also over ontogeny. In the case of studies of nonhuman
primates, there are a number of studies now of nonhuman primates
showing that pieces of the abilities that we see in infants
are shared by other animals, but there's currently a debate
in the field as to whether the entire set of abilities that
we see in human infants are part of our primate heritage of
whether any of them are unique to us. I think that's
a question we have to leave on the table for the moment.
The decisive studies on nonhuman primates just haven't
In the case of ontogeny, I want to throw out a speculation
to you. This is an interesting group, I think, in which to do this
because I believe you may have already heard presentations from some
neuroscientists saying there's really only one system of causal
relationships that underlies all behavior. Human beings are just
complicated machines. Our minds and brains operate in accord with the
same mechanical principles as inanimate objects. And if one takes
these claims seriously, it would seem to suggest that people can come
to overcome this notion that people and inanimate objects are
fundamentally different from one another.
My own experience though, for what it's worth, is that
colleagues who say these things to me about human action tend to
agonize over personal decisions as much as anybody else does, tend to
experience moral indignation. I think that this notion that people
choose their actions and could have acted otherwise is actually very
deeply ingrained within us, and I think we're seeing the origins of
it in these studies with infants.
Okay, I want to completely shift for the remainder of my
time and talk about some capacities that we don't see in other
animals for sure and that we also don't see in human infants but
that we do see in most children at the time that formal education
begins, a set of distinctively human concepts and abilities—one of
the abilities which I didn't put up here is the capacity for
language—that allow us to communicate with one another, to use
symbols and to use abstract concepts that are at the basis of all
science and technology and much of modern life.
Now, what I want to suggest in the case of all of these
concepts is first of all that infants lack them; second of all, that
these concepts aren't explicitly taught to anyone. They develop
spontaneously in children, most children between the ages of about 2
and 5; third, that their development depends, in part, on experience;
and fourth, that their development is absolutely necessary for formal
education, that a child who hasn't developed these fundamental
concepts will be at serious disadvantage in formal educational setting.
Now if I had hours and hours I would try to tell you about
all of these. Since time is very limited, I want to try to flesh out
these claims by looking just at one set of concepts, natural number
concepts. And what I will try to do in my last few minutes here is
begin by telling you very quickly about two core systems for capturing
numerical information that we do find in infants and nonhuman primates,
as well as in us adults, one for dealing with small numbers, the other
for dealing with large approximate numerocities.
Then I want to talk about the construction of the uniquely human
natural number concepts over the course of the preschool years and
then finally, I want to give you a bit of evidence that this construction
depends, in part, on experience. So the first core knowledge system
that serves as a building block for children's number concepts
I've already introduced you to in talking about objects. This
is a system for representing small numbers of objects and all I
want to point out here is that it has some of the properties of
our system of natural number. So this is a system, for example,
that research by Karen Wynn has shown babies are able to use to
do something like compute the effects of adding an object to a scene
or taking an object away from a scene. If you place an object on
the stage, this is again a preferential looking experiment, 5-month-old
infants; place an object on a stage, cover it by a screen, add a
second object to the scene and then ask infants, in effect, how
many objects are there by lowering the screen and presenting either
the right or wrong number of objects. Infants will look longer
if you present the wrong number, and they do that both in this one
plus one kind of problem and also in other similar problems.
Infants can also use representations of small numbers of objects
to make numerical comparisons, and these are studies that have been
explored most thoroughly with older infants about 12-month-olds.
Research in Susan Carey's lab has taken 12-month-old infants
and presented them with graham crackers, putting one plus one equals
two graham crackers into one box. Two minus one equals one graham
cracker into the other box, pushing the boxes apart and encouraging
the infants to crawl to them. And infants will tend to crawl to
the box that has the larger number of graham crackers, showing that
it can both represent the numbers in each box and compare those
But as always with infant research, the limits to
infants' abilities are as interesting as the abilities themselves
and in particular, in these situations we see two general limits. The
first is a domain limit. You see these abilities when you present
babies with solid, manipulable objects. You don't see them when
you present them with nonsolid substances or many other kinds of
perceptible entities and the second is a set size limit. You see these
abilities when you present up to three objects, but when you present
more than three objects babies fall apart.
So here is the results, for example, of the box choice
study, one versus two graham crackers, they go to two. Two versus
three, they go to three. But if you then test with three versus four
or even four versus eight, they're choosing at chance between the
two. They're not able to keep track of more than about three
Now we see the same limits in monkeys. This is research by
Mark Hauser and the same limits in human adults when you prevent us
from counting or otherwise verbally encoding the displays, suggesting
this is the system that shows considerable continuity.
The second system has been revealed through experiments
using an even simpler novelty preference method. For example, a method
that's been used a lot in studies of speech perception where you
take an infant and present them with the sequence of sounds coming out
of one of two side speakers, simply measure how interested they are in
the sound sequence by seeing how long they will turn their head in the
direction of the speaker. Then you can test for their abilities to
discriminate different numbers by familiarizing infants to a set of
different sequences all presenting the same number and then testing
them with new sequences alternately presenting the same number of a
different number. I hope this is clear.
So what's illustrated here, half the babies are bored
with four sound sequences, with four sounds; half with sequences of
eight and then everybody is tested with sequences of four and eight,
and you see will they turn their head to the speaker longer when they
hear a new number?
And very quickly, the findings, the study has been done
with many different numerical discriminations. The findings are at
about six months of age, the first age at which you can use this
method, babies do show abilities to discriminate on the basis of
number. They'll discriminate sequences of four from sequences of
eight, for example. Their number discriminations are imprecise. So if
you repeat the experiment to test discrimination of four from six, they
fail. And what determines whether they succeed or fail is the ratio of
the two numerocities. So a baby who succeeds with 4 versus 8 will
succeed with eight versus 16. If they fail with 4 versus 6,
they'll fail with 8 versus 12.
And finally, as you test older babies, you find that the critical
ratio for discrimination narrows. A 9-month old in particular,
will succeed with a two to three ratio that the 6-month-old fails
Now one can vary the kinds of events or displays presented
to infants to see whether this is an abstract system of number
representation by instead of presenting sequences of sounds you can
present sequences of actions, a puppet that jumps some number of
times. You can also present visual spatial arrays, arrays of dots, of
one or another numerocity. The findings from those studies line up
perfectly with the findings from the studies with sound sequences. If
babies can discriminate a given pair of numbers of sounds, they can
also discriminate that pair of numbers of dots or visible actions.
Now these large number representations show two signature
limits. One that I've already described is the ratio limit on
discrimination. The other limit I also described earlier in talking
about the first system. It's a tracking limit. Babies are able to
discriminate 8 events from 16 events when the events occur in immediate
succession in an object that's continuously visible. But if they
see one at a time, four objects going into a box versus eight objects
going into a box one at a time, and they have to track each of these
individuals as it's hidden, they are not able to use this large
number system in that case. So the same limits have been found in
monkeys and also in human adults, people like us, when we're
prevented from counting or otherwise use language to encode the
displays, suggesting that the second system is also showing continuity.
So it looks like we have evidence for two systems capturing
aspects of numerical information in infants, one focused on small
numbers, the other focused on large numbers, each system showing
successes and failures under a distinctive pattern of conditions.
So the question then is what happens to these two systems,
as children learn verbal counting, as they interact with other people,
and as they develop the kinds of number systems that they're going
to need to use in school?
Now clearly, when children go to school, the assumption is
made that they've got one system of number concepts, not two; that
the system shows neither a set size limit nor a ratio limit. Natural
number concepts allow you to represent whole numbers precisely with no
clear upper bound. And that each number concept refers to a set of
numerically distinct individuals. And the question is where did these
representations come from?
Well, I think some very interesting work that began again
with Karen Wynn and has been pursued by a number of different
investigators since then suggests that these number concepts actually
emerge well after children first learn the verbal counting routine.
So in most American households, somewhere around age 2 or
two and a half, children start engaging in counting. I'm sorry
this is so distorted. There are supposed to be about nine fish on this
table, and if you take an average two year old and say how many fish
are here, the child will very likely go through the routine of pointing
at each of the fish one at a time and going one, two, three, four,
five, etcetera, engaging in verbal counting.
What Wynn showed, though, is that at this early point when
children are engaging in this activity, they don't have the
faintest idea what these words mean or what the activity is about. And
one way to show that is to ask them a simple question. After this
child has counted all nine fish—here's a pair of questions that
shows this. After the child has counted nine fish, you ask the child
would you put one fish in the pond? And the child succeeds. That
shows the child understood the question, is motivated to answer
So now you ask would you put two fish in the pond? And I
can tell you the reaction of my son, aged two years or so at the time
that Karen conducted this experiment on—she was conducting it at the
time, and she came to visit us and did it on him. He looked at her as
if she had suddenly switched to a foreign language. He didn't have
the faintest idea what she wanted, and he then grabbed a handful of
fish and put them in the pond. What her data showed was that at this
point there was no relation between the number asked for and the number
given, except that a child always gave one when asked for one and
always gave more than one when asked for another number.
Now this state persists for about nine months. For about
nine months children are using all of these number words in the verbal
counting routine without understanding what any of them mean. And then
somewhere around age three and a quarter or so, children learn the
meaning of the word two and at that point when you ask for two, you get
two. When you ask for three, you'll get a handful, but not one and
not two. And about another three months later, they learn what the
word three means, and then something magical happens, and they figure
out what the whole counting routine is about.
Now what could be going on here? I think in light of the
work on infants, we can make the following suggestion, that in the
initial step of learning verbal counting, children figure out that the
word one applies when you've got a single object, a single
individual to represent, and the system for representing small numbers
of individuals may support that induction.
They also know that the other number words apply when
you've got a set, a bunch of things, some nonspecific number of
things. When they learn the meaning of two, what they have to learn is
the word two applies just in case your system for representing small
numbers picks out an individual and another individual, and your system
for representing large numbers picks out a set of things, a small set
of things. And then three can be learned in the same way, and then the
child can't go any further because the small number system,
remember the core system, has a limit of three.
But what the child can do at this point is discover that
the progression from two to three and the counting routine involves two
things, adding an individual to the set and increasing the cardinal
value of the set. And once they've got that and can generalize
that to the other number words, they've worked out the meaning of
the counting routine.
Now I've gone through all this because there's no evidence
for any of these developments in any nonhuman animal. This is,
I believe, a distinctively human achievement. And what it consists
of, what the child is doing with support from parents but without
any explicit instruction by anyone is putting together representations
from two core systems with a system of number words and quantification
that's emerged through communication with other people through
their natural language and their culturally specific counting routine.
And I certainly don't have time to give you this evidence, but
there's a wealth of evidence now suggesting that the same three
systems are at work in us as adults when we use and reason about
natural number concepts.
So the last question I want to ask does experience play a
role in this construction? In one trivial sense it must. The number
words of English are different from the number words other languages,
and they have to be learned, but I mean to be asking a deeper
question. Do the concepts that those words pick out emerge, does
experience play any role in the emergence of those concepts?
Now I think there's evidence from the research of two
educational psychologists, Robbie Case and Sharon Griffin, that indeed
experience does play a role. What they showed first is that in the
United States and Canada, although most children from middle class
families have developed these number concepts by the time schooling
begins, many children from disadvantaged families have not. In
particular, Case and Griffin did a set of studies where first they
would take children and have them count and show that all of the
children, these are in kindergarten classes, all of the children could
count to a nice satisfyingly high number, and then they would take
numbers that were in the list that the child had produced, him or
herself, and simply ask questions like if I have five apples and you
have four apples, who has more applies, testing their understanding
that the word "five" picks out a larger numerosity, a larger
number than the word "four."
Now when they asked these questions to children from high
or middle income families, almost everybody can answer them. When they
ask them to children from economically disadvantaged families, they got
a much lower rate of success in kindergarten.
The next question was why would the kindergarten children
from the disadvantaged families be succeeding less? And one
possibility that they pursued was that these children may just not be
having the interactions in their homes that middle class children are
having and that lead children to make this construction spontaneously
on their own. He found, for example, they found that in middle class
families there was lots of talk about number, lots of play with board
games, rolling dice and counting up moves and things like that, much
less of that in the disadvantaged homes.
So Case and Griffin designed a series of intervention studies
where they simply took kindergartners from disadvantaged backgrounds
who tested badly on these number concepts initially and played a
set of games with them, a set of board games, no explicit teaching,
but played games involving talking about number, rolling dice, counting
out moves and so forth and reported dramatic improvements in the
children's understanding of number which were followed up in
one year and three year follow-ups with dramatic advantages in their
formal mathematics education.
So to summarize this, it looks like preschool children
construct natural number concepts spontaneously without formal
instruction, as long as they're given supportive environments.
Without environmental support, it's not clear that these concepts
will develop on their own. Children who don't develop them then
would be at a disadvantage when formal schooling starts, because that
schooling presupposes that when a teacher uses the word
"three" and the child uses the word "three",
they're talking about the same thing. This failure, though
fortunately, the work of Case and Griffin suggests, can be remedied.
Well, I think this general picture applies to many of our most
interesting uniquely human concepts, so I could have given a different
talk about mental state concepts, concepts like beliefs and desires,
propositional attitude concepts. There's good evidence that
infants don't understand these concepts, but that most 4-year-olds
do and that children aren't explicitly taught what beliefs and
desires are, they figure it out on their own in supportive environments.
Similarly, for understanding symbols, young children may
look like they understand symbols when they point to a picture of a cow
and say "cow", but do they really understand that that set of
marks on paper is a representation of a cow, a symbol that stands for a
cow, not a cow itself. There's evidence that that understanding is
not present in infants, that it develops over the years from two to
three or so. The research of Judy DeLoache; again, distinctively human
ability constructed by children without formal instruction, but only in
supportive environments, same for concepts of works of art and tools.
So in each case, I think these concepts are developing in the ways that
natural number concepts did. And I think this suggests that this time
from age two to five is really a critical time in human development,
for the development of a whole host of uniquely human cognitive
abilities, abilities that mark us from other animals and also abilities
that make us capable of formal instruction.
So what I want to do, I'm probably over time, but
I'm just about done, is just end with three general themes and
suggestions that I think this work may support, at least that I wish to
offer to you to consider whether you think this work might support
them. The first theme goes back to the thing you questioned me about,
this preference for novelty. I think it's the case that as early
as we look in infancy, we see that infants are motivated to learn. Now
they're motivated, in part, to learn on their own seeking out
situations that give them new information. But they're especially
motivated to learn from other people, and we see this in everything
from the following a person's gaze to the objects that they're
looking at, to reproducing their actions, to reading through their
actions to the intentions behind them.
But I think a possible implication of this work is that
while infants are built to learn, they're not built to learn
alone. They're built to learn in interaction with other people who
already are immersed in the culture into which they will be growing.
They need social partners to do this, and I think arguably the best
social partners to do this would be one or both of the infant's
In that context, I think you might consider whether our society
is well advised to give so many parents the cruel choice between
having to decide between the economic welfare of their families,
on the one hand, and their opportunity to be there as a participating
parent during the first year of a child's life, on the other.
Should we be requiring single mothers on welfare to work when their
children are infants? Should we be requiring families that require
two incomes to support their children to be choosing between giving
their children that economic support and giving the children the
presence of a full-time parent in the first year? I think that's
one issue worth considering.
The second theme, which I just ended the substantive
presentation with, is that we should pay more attention to the years
from two to five, that this is a critical time for children's
cognitive development. This isn't a time when I think we need to
be putting children in schools or starting formal education. It's
a time when children are learning great things on their own. But
they're only learning those things in supportive environments. And
I think that suggests a further duty that we may have to children that
you may want to consider in this panel, the duty, first of all, of
understanding what are these capacities that are developing in the
years from two to five, and what kinds of environmental support are
necessary for the development of them. The kinds of studies that Case
and Griffin have done for number need to be done, I think, in other
domains as well.
And second, to assure that children throughout our country are
able to grow in environments that provide the resources that they need
for that development.
The final theme is maybe the most speculative one, but for me,
I think it may go the deepest and it takes me back to the first
part of my talk in talking about systems of core knowledge in infants.
Now I think that a general conclusion that's emerged over the
last 50 years is that to a surprising extent young infants, not
always newborns, but 3-month-olds, 5-month-old infants share ways
of conceiving the world with us adults, that they experience the
world in distinctive ways that are much like the ways that we, as
adults, experience the world. And that's true, I think, in
the case of space and objects and other people, the three cases
that I talked about.
But there's a way in which infants are radically different
from us. When we experience negative situations, we're capable
of acting to change those situations. When we find our own resources
for acting are limited, we can communicate our needs to other people
and seek help from them. But infants, though they share many of
our experiences and capacities, radically lack the capacities to
act that we have to ensure that their environments are safe and
healthy, that they're cared for and that their needs are met.
And I think that gives us the most fundamental ethical responsibility
of all, vis-a-vis infants, and that is to care for these creatures
who are so like us in our experiences, but so unlike us in their
capacities to provide their own care.
CHAIRMAN KASS: Thank you very much, Dr. Spelke, Professor
Kagan. The floor is open for discussion.
PROFESSOR SANDEL: Thank you very much for that great
presentation which really covered an enormous amount. I would like, if
I could, to go back to the question about the looking longer test of
novelty, the preferential looking test and what we can infer from it.
Thinking back to that two by two diagram that summarized the study
of children's perceptions of what makes inanimate objects and
people move, contact in the case of inanimate objects, goals in
the case of people, it's a lovely result, so lovely that it's
also a suspicious result because what it discovers is that the way
children perceive the world and the laws of movement recapitulates
the 17th century split between explanation in the physical sciences
and in the human sciences where we concluded in the last 300 years
that mechanism governs the movement of inanimate objects, not teleology.
But the teleology or goal-directed explanations govern the human
sciences, the way people behave, and it just turns out, lo and behold,
that children naturally, so to speak, perceive that relatively recent
discovery, the way that the modern science has bequeathed this split
between the modes of understanding in the physical and human sciences.
So this is really to explore that suspicion.
What's the warrant for inferring from the looking
longer test one thing rather than another? And here's another
experiment, and I wonder what you would read from these results. You
can imagine you could time, never mind children, even adults, how long
some adults might gaze at the sunset or the rising of the sun as those
events naturally occur, familiar though they are, not novel. People
gaze sometimes for long periods of time out of appreciation or
contemplation or who knows what. And then suppose you, as the counter
example, you did an experiment of the kind that occurs in the movie,
The Truman Show. You remember in The Truman Show, unbeknownst to
Truman, he was the character, the Jim Carrey character. He's
living within an elaborately constructed television set where
everything, including the seasons and the weather and the rising and
the setting of the sun is governed by a producer who's in a control
room. And at a certain point this fiction is maintained, but at a
certain point the producer, they're desperately looking for Truman
who has escaped, but it's the middle of the night. And they
can't find him, and so the producer decides he has to spoil the
fiction in order to bring up the lights. And he says "cue the
sun," and the sun rises in the middle of the night. That would be
Now suppose you timed, you applied the looking longer test
to the sun that arose at that unnatural moment, unfamiliar moment,
would people, infants or would we—would you expect that we would look
longer at that unnatural, unfamiliar rising of the sun, than we do when
we sit in contemplation of a natural sunrise? And how would you know
if we looked longer at the one rather than the other that one was novel
and the other familiar?
PROFESSOR SPELKE: Right. Actually, in that case, I think we
probably would. If the sun suddenly rose in the middle of the night, I
think we'd all run outside and look at it. However, I completely
grant your general point. And in fact, the reason I went through the
whole discussion of the Held experiments is that for any given behavior
that an infant chose, looking longer at one thing than at another, we
could tell multiple stories about the causes of that behavior.
That's absolutely true.
So one thing that I had to do in making this presentation
because I wanted to cover a lot of ground was give you the results of
single experiments, but it's when you look across experiments that
I think the following things emerge. First of all, it is not the case
that infants will absolutely and under all circumstances prefer
novelty. That's not true any more than we as adults will always
prefer novelty. Actually, one case I think in which it's least
likely to be true is cases involving human action where if other people
do things that are bizarre, we may avert our eyes from it rather than
look at it. So it's not at all the case that one can take as a
given whenever an infant looks longer at something, that must be more
novel to them.
However, within a series of experiments what you do in these studies
is the following. You start with an analysis of an ability. Under
what conditions would we, as adults, see something as goal-directed
or not. Then you make a set of focused predictions about what you
would see in an infant if they had the same system for representing
things as we have. And then you test down the line whether those
predictions hold. Now if you get a coherent pattern across them,
all involving when you change something in a way that would lead
an adult to say that's funny, the goal just changed, the baby
Across that series of studies, there isn't a coherent
explanation to give if the baby were preferring the familiar one and
there is a coherent explanation to give if they're preferring the
novel one. So that's one answer to your question.
The other answer to your question, though, is that both in
the case of research on infants' reactions to people and in the
case of research on infants' reactions to inanimate objects, the
examples I gave were all preferential looking experiments. But in fact—actually, they weren't all. In both cases, multiple methods have
been used to converge in on the same abilities. So for understanding
infants' representations of other people's actions, you can use
imitation tasks where they repeat people's actions and ask is their
repetition true to the goal or is it true to superficial properties of
the actions? And the answers you get from those studies converge with
the looking time studies.
Similarly, in the studies of object representations, you can ask
what do babies see as the bounded objects in a scene, either using
preferential looking with the assumption of a novelty preference
or by using reaching, and you see a convergence across them. So
I think in both cases it's the converging findings of series
of studies within each method in relation to adult abilities and
also series of studies across methods that lead to these conclusions.
And you're quite right, that if you single out any single experiment,
then you're in the situation that Richard Held was in when he
only had the first experiment on the 4-month-old infants looking
longer at the side with double image stripes than single image,
and you don't know what the basis of the response is.
CHAIRMAN KASS: Bill Hurlbut.
DR. HURLBUT: If our question here, fundamentally, is
nativism versus empiricism, I want to ask you about the sort of fullest
form, that being the development of the moral mind, because building on
what Michael was just talking about, I believe there are studies that
indicate that infants will look at things, certain things, longer than
others based on what you might call intrinsic value. So, for example,
you mentioned faces. There are studies that indicate that certain
faces rated as attractive faces by adults and across cultures command
the longer attention of infants. Now that's really amazing. That
means somehow—and this is quite early infants, I believe. Some sort
of pattern, and it's not just symmetry, some pattern has an
intrinsic value. It's built in, it would sound like. And
that's the first thing. I'd like you to elaborate on that.
The second thing is not just intrinsic value, but the roots
of our relationship between awareness and action. You cited
Meltzoff's work of imitating faces. When you stop and you ponder
that capacity, that again requires that the infant somehow has a
pattern that it knows sensorially how to apprehend, but also how to
Now I know there are some findings that suggest there are cells,
Rizzolatti's so-called mirror cells that could mediate this.
But it would imply that quite high order constructions that somehow
there was already a connection between sensory input and motor action.
And of course, the concomitant of that is that if there is motor
action, even with a sensory input, that the subjective states that
accompany those muscle actions would already be communicated in
a kind of inter-subjectivity. All this seems to add up to a foundation
for the moral mind.
Can you just comment on all of that?
PROFESSOR SPELKE: Sure. On your last point first, I think
there's actually quite rich evidence that babies are sensitive
really early to the correspondences between their own actions and other
people's actions. One thing I didn't talk about from the
Woodward studies is that if you look at the kinds of actions that
babies can attribute goals to, they develop hand in hand with the
child's own capacities to act. So it's at the point at which a
child, him or herself, will start pointing to objects, that they will
interpret a pointing action that they see another person perform as
goal directed by the Woodward test. So I think that goes along with
your line of thinking.
And you're also quite right that we don't know
whether this is unique to humans or not. There's clearly pieces of
it in monkeys as shown by the Rizzolatti work and other work like that.
I'm going to have to punt on the morality question, not
because I don't think it's important, but because I really
think that the jury is out. There are hints of pieces of what will
become a system of moral reasoning that I think we can discern in
infants, but whether we have a full blown system that's showing
itself in a glimmer here and a glimmer there, or whether a full blown
system of moral sense is going to require the kinds of constructions
that a system of numerical reasoning requires, constructions that
children will put together, perhaps without explicit teaching, perhaps
learning by example and by observing other people. I think we just
don't have the evidence at this point to say.
There's, of course, a long tradition of studying moral
development in children. I think unfortunately much of that tradition
has focused not on children's moral intuitions, but on their
justifications, and then what you find, not surprisingly, is that young
children who are pretty terrible at giving coherent justifications for
anything they believe, don't give very sophisticated looking moral
But the question of whether they have underlying
intuitions, like our intuitions as adults and whether there's a
core to morality is, I think, going to be a very interesting and
important question to pursue, and we don't have the answer yet.
DR. HURLBUT: Can you say at least a little bit about
intrinsic value, like beauty in faces?
PROFESSOR SPELKE: Here I want to voice some of the skepticism
I think related to what Dr. Sandel was saying before. We can say that
a baby will look longer at one thing than another, but do we know that
that means that they're esteeming it, that they're endowing it
with value? I'm not sure that we do. But maybe Jerry—I think
this goes out of my domain of sort of cold cognition and into emotion,
and maybe Jerry wants to speak to that?
PROFESSOR KAGAN: Babies prefer symmetry. I thought Liz was
going to say that actually, and that's why, they prefer vertical
symmetry so I agree with Liz. They don't understand beauty or that
that face is pretty, but they will look at vertically symmetrical
designs, and pretty faces are vertically symmetrical.
Incidentally, that doesn't mean that I don't
believe that biologically human children don't inherit a foundation
for moral sense. They do somewhere in the second year, but I don't
believe they have it in the first six or eight months of life. They
get it later.
CHAIRMAN KASS: I have Janet, Ben Carson, Mike Gazzaniga and
DR. ROWLEY: I actually have three questions, if I may, two
probably for Liz and one for Jerry.
So neither one of you actually talked about the change in
the complexity of the brain connections that develop over time and
focus really, you focus on early cognition which is certainly
important, but all of the evidence, of course, which I know you would
agree with, that the brain certainly matures over a long period of time
and so there are certain kinds of skills that children should be
exposed to and experiences they should get relatively early, but then
there are other things that are going to evolve later, and trying to
force a child to learn some things at three or four is futile or
Would you say a little bit more just in general about
conductivity, and then I've got two more parts.
PROFESSOR SPELKE: I agree completely, and I think one of the
values of the work on cognitive development is there's a huge gap
between what we understand about learning and cognition on a functional
level and what we understand about neural growth and conductivity on a
structural level. So I think that the beautiful work on neural
development tells us to expect that children will be optimally ready to
learn different things at different ages, but it doesn't in itself
yet tell us what things they're ready to learn at what ages, and we
need the behavioral work to do that. And I quite agree with you. For
example, based on the work that I presented on number, I think it would
be futile at best and possibly harmful to be pushing infants or very
young children to be developing mathematical concepts before they even
have a system in place for representing them, and I think there's
many cases of that where we can use work on basic cognitive development
to make more informed decisions about what children are ready to learn
at different ages.
DR. ROWLEY: Now the other—one of your final concerns
or practical consequences of what you've described was that
it's very important for parents to be able to be with
their children for the first couple of years of life and you
weren't really in favor of child care at that point.
But the concern is that there are, unfortunately, a fair proportion
of families in the United States where the parents themselves
are not really in a position to give the children these kind
of early stimuli. And so I wonder if there isn't really
a place for child care and nursery schools at a very, very
early age for—at least some availability for these, some
portion of the population.
PROFESSOR SPELKE: Thank you for that clarifying question. I
did not mean to be arguing against child care. I mean to be arguing
that every infant needs to be growing up with adults who are responsive
to them, who have the time to take to be interacting with them, to be
attending to them, that infant development doesn't happen in a
vacuum. And in many cases, it's the parents who would want to be
playing that role if it were economically possible for them. But that
is not to say that a biological parent is the only person who can play
DR. ROWLEY: And finally, the question for Professor Kagan,
when does a sense of right and wrong or moral judgment really develop
in children? It's partly a question that Bill asked, but we
didn't get into—when can you really hold a child responsible and
what kind of actions can you hold them responsible for?
PROFESSOR KAGAN: Three stages in moral development which I
believe are universal. In the middle of the second year, if you're
late by, I don't know, 30 months, but most kids by 2, understand
the concepts right and wrong, good and bad, in their language. They
have a concept of prohibited actions. That's not morality, but
that's the beginning.
Between five and seven, and that's why the Church and
English Common Law and Freud and Piaget, I mean everyone knows that a
profound change in brain occurs between five and seven. We don't
know what it is. Now children have a more abstract concept of good and
bad and understand that going to school is good and watching the cow
from 9 until dinner is something I should do. Now we hold them
responsible. And the last phase is at adolescence, again, I think a
maturational change occurs, of course, all supported by the
Now one has, one looks for consistency and one looks for consistency
in your beliefs which 7-year-olds don't. So the child of seven
can hold these beliefs. My father is a wonderful man. My father
is much too harsh with my mother. One of those has to go. That's
the change in adolescence. Now the adolescent seeks consistency
among their moral premises, and that's the last phase maturationally.
Of course, experience and culture—morality is like language.
You're given the capacity, and now you're culture teaches
you whether you're going to learn Swahili, French or Germany,
and your culture teaches you, with the exception, I think, of unprovoked
aggression. I have the intuition that that is universal. But with
that exception it teaches you what is moral and what is immoral.
CHAIRMAN KASS: Ben Carson.
DR. CARSON: Thank you both for those illuminating
discussions. This morning we talked a little bit about the neurophysiological
and anatomical aspects of the developing human brain and this afternoon
more about some of the cognitive social developmental issues. In
both cases, there's an implication that the nurturing environment
plays a very significant role, it provides very significant advantages.
I was particularly struck by the slide that indicated the numerical
reasoning at a 95 percent versus an 18 percent range in children
in nurturing environments versus those in lower socio-economic classes.
The question is is there a point at which it is too late to
close the gap? If so, what is that, and secondly, how do you explain
PROFESSOR SPELKE: Both really good questions. The work
of Case and Griffin is actually, I think, very encouraging here
because although the middle class children tend to develop these
concepts in the years from two and a half to four, their intervention
was aimed at 5-year-olds starting kindergarten and it was not too
late. The 5-year-olds in their program did extremely well. That
doesn't tell us is there a point later on that is too late.
There will be a cumulative problem though if you wait too long which
is that when kids start elementary school, they're getting exposed
to a whole curriculum that presupposes that those concepts are in
place. So if the concepts aren't in place, even if the child
is biologically still capable of gaining them, they're going
to get further and further behind because what the teacher is saying
is just not going to be making any sense to them. So I think just
on those grounds one would want, these kinds of building block concepts,
one would want interventions that put them in place at the time
that formal education begins.
On the issues of late bloomers, I think there's lots of
reason to think that nature is flexible and there are many paths to
success and many different rates and patterns that children will follow
to get there, and I don't think it follows from any of the work
that Jerry or I talked about today. In fact, certainly not what Jerry
talked about, but not the work that I talked about either, that there
is one royal road that one must progress down and one specific time
table to get there.
PROFESSOR KAGAN: There's a difference between the
ability to reason and where you are in the rank order. And this
is where you are in the rank order. A great moment for me when
I had a sabbatical leave 30 years ago was to sit on the edge of
Lake Atitlan in northwest Guatemala with illiterate Mayan Indians
who had no schooling and asking 12-year-olds what would happen if
the lake dried up and getting perfect syllogistic reasoning.
I agree with the thrust of Liz's talk. I mean, look at
the conditions under humans grow up. We have to have a basic set of
cognitive abilities, but in our societies, technological societies, it
doesn't make any difference how good your reason, that's
irrelevant. It's where you are in the rank order because we can
have just so many chiefs, and that's the problem. We don't
want to confuse that. We don't want to confuse the class
differences in rank with the ability to reason. That would be very
CHAIRMAN KASS: Mike Gazzaniga.
DR. GAZZANIGA: Are you sure we have the time?
CHAIRMAN KASS: No, go ahead. Let's take just a few more
minutes because we don't want to lose again the benefit of having
DR. GAZZANIGA: First of all, I hope everybody appreciates
how Jerry and Liz asked these fundamental questions of biology in
the most low tech imaginable way with looking longer at a stimulus.
You didn't get into the peek-a-boo experiments, but they're
as captivating. And sometimes I think we should throw our brain
scanners out and just give the field to these two and have them
answer questions for us. But once you get past the critical period
issue here and where you might have said constructionist ideas were
needed to bring the kids along to get them up to the sort of the
level of conceptual development that you might just call baseline
normal level, but then you've introduced this idea of the social
context, so you really don't know what it is that's going
on. Something is going on that's needed in a group of kids.
Now let's imagine that we've got our group of kids
up to the baseline level. And now you're trying to introduce other
concepts where people start to differentiate in their understanding of
the world. So you want to teach Newtonian physics versus our natural
naive physics. What then? What are the tricks you have up your
sleeve? Are there tricks up your sleeve that can bring along the next
level of conceptual thinking, and is there a level, a definable level
where you start seeing separations that are very hard to overcome on
any social group?
PROFESSOR SPELKE: Yes. One of the things that I was sorry to
have to leave out of my already too long talk was the evidence that
when adults reason about number or physics or other things, we bring
together the same core systems that we see children using when they
assemble these concepts in the first place. I think the general answer
to your question is that at any point in the educational system the way
education works is that it builds new concepts out of old concepts and
that the way to get a child, a high school student, to understand
Newtonian mechanics is not to ignore their intuitive notions of
mechanics which are profoundly not Newtonian, right, there's no
action at a distance and so forth, not to ignore them but to work with
them, to work with them and to build on them and then by connecting
them to their intuitive number concepts, to see that there's a
problem with them. And that there's another way of thinking about
how objects move, building on what you know about number, that does a
better job than your intuitive notions of how objects move, building on
this kind of Medieval or Aristotelian notion of things in motion and
giving forces to each other.
So I think at every step of the educational system, good teachers
intuitively figure out what people's pre-existing concepts are
and work with them. And because in many cases, especially early
on in the educational system, it can be extremely difficult to intuit
what the concepts are of a child when they're different from
yours. The research can be helpful in helping teachers to understand
and that can be helpful for designing curricula that takes those
concepts and build on them.
CHAIRMAN KASS: I'm next in line. I want to make a comment
and then a question.
The comment is partly inspired by Mike's question and
your answer. I understand that the core knowledge is somehow the
foundation and one builds upon that, but there really might be certain
kinds of real discontinuities and in the area of number you'd have
the primary case because the modern concept of number bows the
difference between a multitude and a magnitude so that you have a
number line to which—a Greek would find it unintelligible.
A number is a discrete multiple and to have a line in which
each point is somehow a number and that you blow the difference between
the discrete and the continuous is strange. And you've got to
somehow overturn your fundamental idea of multitude in order to acquire
the modern idea of number, but that raises some kind of question about
the difference between the things which are somehow naturally ours and
the things which are somehow acquired as a result of new conceptual
schemes, and some people have a hell of a time learning algebra which
is based really upon our Cartesian coordinate system.
The question and you can comment on that if you'd like,
but the question really has to do with the division of labor in this
discussion between the cognitive capacities, and let me give to Jerry
Kagan not just questions of temperament, but also emotion, motivation
and interest. And I wonder whether this perfectly respectable division
of labor doesn't introduce—isn't based on a kind of
distortion in which the question is whether crucial to cognition are
not just the native capacities for discrimination and awareness, but
interest, desire, motivation and concern.
One could talk about the game playing way of remedying, a
board game way of remedying the difficulties in numerosity either as
the acquisition of cognitive ability or as actually caring about the
matter because there's winning and losing involved and somehow
certain kinds of things now come to the fore. So I'm wondering
whether this sort of bifurcation of cognition and motivation or
cognition, temperament, emotion and drive, whether that's an
accurate representation of how we should be thinking about how children
Aristotle's remark "all children by nature desire
understanding," that's somehow put all human beings, but
begins really in childhood. And I just wondered whether you would
comment on how the two sides of the street meet in your own
understanding of what we're talking about here.
PROFESSOR KAGAN: Yes, I'll be brief, and then Liz might
want to add. I don't think temperament has anything to do with it,
but emotion does. As Liz intimated earlier, all humans as a species
enjoy mastery. That's not a new idea. They enjoy understanding
and enjoy using their talents at the next level of challenge. But we
can't run a society that way. That is, each society has a set of
requirements, and we know the requirements for technological
societies. They require reading, mathematics, writing essays. Those
aren't the tasks that come naturally. So we are forced, we must
say to children, I'm sorry, these are the tasks that you have to
master. They are less natural to the human species.
Now we need motivation, special motivation, acquired
motivation. This is what Liz was driving at, why we need parents. And
because no human being, child or adult, will invest energy at a task
they do not believe they would be successful in. An animal won't
do it, and a human won't do it. So once you have a child in grades
one, two, three and four who comes to the decision every child able to
do this except those with a damaged brain, that there's no way
I'm going to be in the top third of my class. There's no way
that I'm—because there's no idea of absolute skill. It's
always relative, right? The adults and the peers determine what is
called mastery. And so by grades four or five you lose motivation.
That is the boat we're in and so the task is not to say yes, we
won't teach you any reading, what do you wish to do?
The task is to devote more effort to the children who are
behind. And now my last point, not just in America or Europe, in every
country, every country where this study has been done, the lower the
educational level of the parents, the poorer the academic record,
period. Class is everything.
There are studies. NIH spent $50 million on the effect of
various forms of day care, home care, home alone. This is a very
famous study. And when you look at the data, the best predictor of
cognitive performance in the second grade is the class, and after that
everything else has trivial variance. This is the issue that we have
to deal with. It's profound. It's not just—it's our
problem in America, seriously, but it's a problem around the world,
and we have to get—we have to communicate, we have to do more for
those who are less well educated in our society to get them to
understand the importance of the task requirements we set for children
in our culture. They don't understand it. Many of them are
fatalistic. That is a very difficult job.
Now speaking for myself, I can imagine no more important
task this nation might undertake, no more important task.
PROFESSOR SPELKE: Let me just add that I think—I agree with
what Jerry said, but I think that in addition to children having an
intrinsic desire for mastery, there's an intrinsic desire for
connecting to other people for becoming able to do the things that
other people are doing and that this is driving much of the
observational learning and of coming to gain the skills that mark the
people in their community and in their culture and that, on that basis
I completely agree with you.
Certainly in the preschool years, the division between
cognition and motivation or emotion which is useful for figuring out
how to organize talks is quite artificial, and any program aimed at
children to enhance their cognitive development is going to need to be
building on these needs intrinsic to children to be connecting.
If I can just say one thing quickly, though, about the point you
made about number, one of the reasons that number is so fascinating
is that both in the history of mathematics and in the education
that children and high school students and college students go through
in studying mathematics now, we see a progression of revolutions
in the concept of number. I think the first revolution is the one
I talked about between age two and a half and age four, where children
go from having two quite different notions of number, neither of
which has the power of the natural number system to constructing
the natural number system. And although this is partly an expression
of faith and only partly based on data, I also think that if we
turn to the later constructions, understanding of number lines,
constructing notions of rational numbers, real numbers and so forth,
the general story that one advances to a new level of understanding
by taking one's pre-existing understanding, in this case we'd
have to look at understanding of points and lines and spatial intuitions,
which I didn't talk about at all, but which young children have.
One takes these, one connects them in new ways and often with the
help of teachers who can point out what connections are useful,
what properties of points and lines are useful in thinking about
number? You then get to a new level of development.
CHAIRMAN KASS: Briefly, Robbie and then Peter and then
PROFESSOR GEORGE: Thank you. Anyone who has been a parent or
even an older sibling knows what a pleasure it is to observe the
reactions that children have to various things. It must be wonderful
to be able to do that in a professional capacity as well and be paid
for it. And, of course, it was very interesting material that you
presented to us from so many sources.
My impression is that—I want to ask you about something
that hasn't been raised yet, which is research ethics. My
impression is that while anyone who works with human subjects is
working under fairly strict ethics rules, that when it comes to working
with children there are an even richer set of ethics rules, and I
wondered if you could say a little bit about them, and I'm
particularly interested to know whether the ethical norms that apply in
working with children are truly salient or whether they're mostly
or merely symbolic. In other words, do we sacrifice some knowledge?
Do we sacrifice some advances for the sake of respecting those norms
that are meant to protect children?
PROFESSOR SPELKE: Yes, we do, and I think it's an
excellent thing that we do, and one can't subject children and one
shouldn't subject children to any of the controlled rearing studies
that one can do on other animals. One would be very wary of subjecting
children to any kind of stressful situation. I mean, our own rule of
thumb for our experiments is the parents are always present during the
studies. They should be completely happy at every second for
what's going on, with what's going on in the study. It should
be the kind of events that go on in children's lives or that the
parents would want to see going on in children's lives outside the
lab. So I think the standards are very high, particularly for research
like mine where there is no immediate benefit to that child. We're
asking basic questions about the development of human knowledge. We
hope that the answers to those questions will be a benefit to society,
in general, but we have no illusion that the particular child who comes
in for our study is going to benefit. So they better have a very good
time and experience no negative consequences from being in the
PROFESSOR GEORGE: Now in foregoing some knowledge for the sake
of respecting ethical norms, the norms themselves, I take it, cannot be
supplied by science or by scientific reasoning? Is that right?
PROFESSOR SPELKE: I don't know about the history, how the
ethical norms developed actually.
PROFESSOR GEORGE: In other words, are they themselves the
fruit of scientific inquiry or are they—do they come from another
PROFESSOR KAGAN: No, they come from the consensus of a society
that one does not cause distress.
PROFESSOR GEORGE: And that itself is not a scientific—is it
a rational concern?
PROFESSOR KAGAN: Moral choice.
PROFESSOR GEORGE: It's a moral choice, but one that comes
to science from the outside. Okay. thank you.
CHAIRMAN KASS: Peter's last comment.
DR. LAWLER: On the basis of what you said, couldn't
you argue that they could come from what we know about the distinctive
nature of children? They could come from science, right?
PROFESSOR KAGAN: I'm sorry, I didn't hear the
DR. LAWLER: The moral norms, the ethical norms,
why couldn't they come from—what you two do in such
a great way is restore the idea of a distinctively human nature.
We're distinctive in many respects, but we're also
natural beings. We have these potentials which are actualized,
right? So given all that we know about the nature of children
in some ways as distinct beings, social beings who take a
joy in learning and everything you've said, why couldn't
the norms come from what we know through science?
PROFESSOR KAGAN: I hope you meant that to provoke
me. I hope I speak for Liz. Science is a wonderful thing.
It's one of the great, great human missions, and those
of us in science feel privileged.
Do not look to science for moral norms. Science tells us
that male primates are promiscuous, therefore we should change
the norms of adultery? No? No. Science tells us that most
boys are much better at spatial problems like geometry than
girls. Therefore, we probably should have sex segregated
classes for teaching geometry. A referendum next November
would be defeated by Americans who are wise. Wittgenstein
understood this. The ancients understood this. Jim's
written about this in his book The Moral Sense.
Morality is very special. Very special. It has to do
with the sentiment of community, and that lies outside science. We
want to say to the scientists the following. Thank you. Those are
very interesting facts, very interesting, but in this instance I
don't choose to implement them, and that's neither silly nor
CHAIRMAN KASS: We're going to stop. Thank you both, very,
very much for a wonderful afternoon and also for the work that
you're doing. This is really eye opening and very important
foundational work that will, I'm sure, benefit all of us.
To the Council Members, we're behind as we so often
are. We had left the last hour, it will now be closer to half an hour
for stock taking and discussion of development here. I see there are
motions to adjourn. We can't partly because this Ethics Council is
required by law to be instructed about ethics. We had an ethics lesson
the very first time we met. I think we escaped by somebody's
inattention. I think we require these annually, do we? And someone
forgot to give us lessons in ethics last year, but someone will be
arriving at 5:15, so you can't leave. We'll take 15 minutes.
We'll talk amongst ourselves. Thank you to our guests.
(Off the record.)
SESSION 4: NEUROSCIENCE, BRAIN,
AND BEHAVIOR III: COUNCIL DISCUSSION
CHAIRMAN KASS: Could we get started, Dean? This last
session, it will be abbreviated, and it will have to be followed
up by some staff work with your advice to take us to the next
stage. This last session, abbreviated because we've been
behind for most of the day, is supposed to be devoted to council
discussion in which we are to take stock of what we might
have learned today, about what new kinds of knowledge and
inquiry we would like ourselves to pursue and how to formulate
any implicit ethical or social issues that are here, and also
to raise for ourselves other kinds of topics in this large
area, not only deserving of our attention, but in a way ripe
for our attention.
I mean, there was some discussion at the very end of Dr.
Jessell's presentation about how soon one might be able to move
between these neuroscientific findings and our interests in behavior,
and we got a rather, an answer which says not for awhile, and that
means that somehow we're trying to move rapidly from that to some
kind of issue worthy of our attention. Important though those studies
were, if one's looking for somehow the secret of preventing
abnormal behavior or mental illness, we've got a little time to go.
This is a large and inchoate area. We are attempting to
find out whether this is a topic for us or not, even as we
are learning some very interesting things. I've asked
Mike Gazzaniga if he wouldn't mind too, and if you want
to wait, I'll sing a song, to offer something in this
It was partly, indeed, on the basis of suggestions that you
made last time, and Janet and Dan Foster, where the question was well,
we really ought to learn something about what people know about normal
brain development and early childhood development before we wander off
into some more esoteric topics. The suggestion was well, if you want
to—there was a discussion whether we should read these things and
treat them as background, or whether we ought to hear them in the flesh
from people who are working in the field.
Speaking specifically for myself, it was very, very good to
have the live presentations of people who are in the forefront of these
neuroscientific and psychological studies.
Mike, would you be prepared to say something about what
have we learned today that's relevant to our own ongoing work, and
can we begin to formulate certain kinds of questions for further
investigation? By the way, I'll set a limit on this discussion
for today of 5:15, 5:20, so we're not going to go over. This will
be a start, and we will continue with staff prepared papers and the
like. We're not going to cheat on your free time.
DR. GAZZANIGA: Well, don't worry about my taking the
time. As I reconstruct this in my mind, we were having a conversation
last time about possible issues in neuroscience that might bubble up to
the level of an ethical concern. A conversation was starting on those
various issues, and some of them are fascinating issues in
neuroscience, and they moved all the way from looking at issues of
consciousness to issues of determinism and all the like, down to issues
of, perhaps, intervention in early education, and what was the nature
of what we know about neurodevelopment that might make that rise to the
level of ethical concern.
Now, oddly, even though I love all those topics, I'm
not really pushing this because I don't know that, given the
mandate of this council, that those issues are appropriate for the
council in the sense that if we are supposed to be looking at biotech
advancements that impact society at large, I think these issues of
neuroscience are very active, very fascinating, very interesting, but I
don't see any huge issue around the corner that is being provoked
by our knowledge of neuroscience. I may get a lot of pushback on that
from my fellow neuroscientists, but that is sort of my take on things.
I think there are things to be discussed, but I don't
think there's urgency to it in a sense like there has been with the
cloning issue and all that is associated with it.
On this particular issue that we examined today, the point
was to sort of bring everybody up to speed on how one thinks about how
much comes with the baby, with the child, how much conceptual work is
already done by the process that finds us all being humans. Then in
that context, if you understand that, what you might mean about a
deeper learning experience, deeper educational experience.
So, here we had today a wonderful discussion on the
richness of the concepts that the young child comes with, basically,
and the limits on those and then how those are developed and how
they're sometimes not met in this critical period and so forth and
so on. So, those are general interests, and unless we want to get into
the social policy questions that were raised indirectly or directly by
Dr. Spelke, I'm not sure where the ethical question is. So, I
really yield to how you want to think about this.
I don't know—I'm not pushing an agenda here.
I'm just trying to think out loud about where ethics meets the
advancements in neuroscience in the context of this council.
CHAIRMAN KASS: Let me make a small comment on that, and
I'm sure others would like to get in on this as well. I read from
the mission as stated in the Executive Order. "To undertake
fundamental inquiry to the human and moral significance of developments
in biomedical and behavioral science and technology, to explore
specific ethical and policy questions related to these
Ethical questions need not be conundra. They need not be
things that are highly changed, and policy questions need
not only be those things about which we are divided. There
seems to be at least a certain human significance to the kinds
of work that's being done here insofar as it bears upon
early childhood education and the prospects for rearing well
the next generation in a world in which we don't do that
all that well.
I'm not proposing that that be our focus, but I
don't think it would be outside the mandate of this body to think
about, and this was the force really of Ben Carson's question and
the way of Janet's questions. How does this somehow translate into
education. Is it too early to offer certain kinds of suggestions
there, or is there some kind of social significance of the things that
these people are showing us, and should we find out more?
Again, I'm not pushing that either, but I wouldn't
say that this is off the table and irrelevant to our mission, at least
insofar as the mission is described.
DR. GAZZANIGA: Just to finish my little—there certainly
are large social issues and implications to this. I think it's a
shift in what the council has been considering if we go there. I just
leave it for the council to advise and consent on that.
CHAIRMAN KASS: Yes, I'm not proposing it as a shift.
I'm not proposing that shift, but I'm saying that it would fall
under the larger umbrella that we have.
Let's see, I had Rebecca and Jim Wilson, and Robbie and
Alfonso, and Ben.
PROFESSOR DRESSER: Well, I wanted to push my—first, one hopes
that policy decisions rest on some ethical views or judgments. So, if
you're talking about policy implications, it seems to me underneath
there would be policies putting into play some sort of views that about
right and wrong or what's good and what's bad.
You said that some of your colleagues would disagree with
you that, you know, it's premature to start talking about
applications, but I wondered, what would your colleagues who disagreed
with you say are issues that are social issues with ethical
DR. GAZZANIGA: Well, I say that in the context that we
have put out this book called "Beyond Therapy," which
addressed a lot of the issues that are currently being discussed within
the neuroscience community of enhancements, the memory issues, and all
the rest that were reviewed in that book. So, we're trying to get
beyond those. We've done those, and move forward.
So, if the "Beyond Therapy" effort had not been
completed, then we could go through that whole list of things that we
discussed for six months.
PROFESSOR DRESSER: What about free will and criminal
responsibility and education? You can't think of anything?
DR. GAZZANIGA: I mean, those are all issues. I'm not
sure that the neuroscience twist on it, though, is that tight at this
point. Those are issues that can come out more out of the sort of work
that Liz Spelke talked about and then any deep understanding of the
neurocircuits involved in learning.
CHAIRMAN KASS: Jim?
PROFESSOR WILSON: In order to sharpen the discussion, let me
make two different kinds of proposals for what we might do next.
I'm sorry I was not here at our last meeting. I was traveling on a
trip that I much preferred to being with all of you people, much as I
I think that there are two issues which have policy
significance which have deeply involved medical and biological
implications. One we will talk about tomorrow, and that's the
problem of aging. We will hear from Rebecca and Gil and others about
how you manage an increasingly aging population when people are trying
to assert for themselves some degree of authority over how they shall
end their lives or what kind of treatment will be provided. I think
this is a terribly important subject.
Allied to it is a second subject that is also related to
aging, and that is organ transplants. Medical science has become
extraordinarily skilled at transplanting organs. We're getting
older. The demand for transplanted organs will get greater.
I do not believe personally, without having made a deep
examination of this, that we necessarily have a very good system
whereby we either collect or distribute organs. The ethical questions
that arise about how you collect them and how you distribute them and
indeed what you do with them, it seems to me are very important.
Now, this is a lot different from talking about criminality
and free will. If you're going to talk about criminality and free
will, about which I've written a great deal, tell me when
you're going to do it because I don't plan to attend that
session because I can assure you that there is nothing to say on this
topic, having gone through countless seminars about it.
If you want to talk about something where there is a clear
bioethical problem, these two aspects of aging strike me as being quite
CHAIRMAN KASS: Robbie?
DR. GEORGE: Well, if everybody's in the mood for
another rumble, I can think of a good topic that we could generate a
lot of divisiveness about, which is the topic that was suggested in the
one area in which our guests made some suggestions towards social
policy, and that is education. Of course, we begin with a shared
conviction. I'm sure everybody believes that it's better for
children to be placed in circumstances and given opportunities and
resources to fulfill their abilities. We all want that for our
children and for everyone's children.
But it would be interesting to know what the best science
had to say about the desirability of putting children between ages two
and five in schools or daycare centers or having them in homes, having
in mind what Janet said about the inability to completely generalize
here and imagine that the answer is going to be the same for
everybody. There are special circumstances.
Even trying to decide that question, I'm sure, would be
very controversial, and we would probably divide over it, but gee,
I'd like to know the answer to it, and I'd like to know
what's out there by way of research that would lead us to be able
to at least form some tentative conclusions.
Having said that, let's just say for the sake of
argument, and I'm not trying to prejudice the case. Let's say
for the sake of argument that all things considered in most cases,
it's rational to conclude based on the science that we would look
at that it's better for kids to be between ages two and five, to be
at home with a parent, or someone who is functioning very much like a
parent rather than being in a school or a daycare center or something
Well, then of course there would be a profound division
about how you create social circumstances or what social policies would
facilitate that. I've heard this argued at completely polar
extremes. Some people say that well, what that puts into place is the
predicate for the establishment of a true form of socialism where
through a heavy taxation system, we would put the government in a
position to be able to provide resources that would enable people to
keep kids at home who would otherwise have to be in the work force.
Then there are other people who say at the opposite extreme
that what created the need for the two earner family was the
Constitutional amendment that authorized the income tax and what we
should do is abolish the income tax and solve the problem that way.
I can imagine us usefully discussing, although it would be
extremely controversial, usefully discussing and having our staff look
into and having us read studies about what's best for kids between
ages two and five. I can't imagine us usefully debating then the
policy question, should we abolish the income tax, should we establish
some form of socialism or something like that.
So, if when we went down this road, I think we could only
go down so far, not toward any concrete policy conclusions about how to
make it possible for people to have a parent at home, but only looking
at the question whether all things considered, our society is heading
in the right direction by having an awful lot of kids, perhaps most
kids today between two and five, in some sort of daycare situation.
CHAIRMAN KASS: Yes, thank you. Let me make a procedural
suggestion. Jim Wilson has added non-neuroscience questions to
our agenda. One of them we will take up tomorrow, and he has put
forth the business of organ transplantation. Let's keep the
rest of this discussion still on where we might be on this topic.
We are free to abandon it if it turns out that we cannot make it
tractable or focused. This does not preclude adding other topics,
at least for provisional consideration as we go along. Jim?
PROFESSOR WILSON: Early childhood education, as you may know,
currently involves a major study effort by the National Institutes of
Health that involves several dozen scholars around the country. They
regularly produce reports. The reports are filled with conflicting
interpretations about what the data mean, and conflicting ethical
arguments about what they ought to mean.
If we're going to look at this, I suggest it will take
some deep staff work into what the National Institute has done in this
area to see if there's anything left over. I say this, urging us
to bear in mind that in our second reincarnation, we have roughly seven
CHAIRMAN KASS: I have Alfonso, Ben, Peter, and Michael.
DR. GÓMEZ-LOBO: I'm going to contribute to the
rambling I guess in a way, but I'm going to go back to the question
of neuroscience, just to give you my personal thoughts.
First of all, I've enjoyed these two meetings, the meeting
today and the last meeting tremendously. I mean, it's
really fascinating to hear people who really know a lot about
these things, and always initially divided in my mind in the
On the one hand, it seems to me that any ethical concerns
would have to do with actions, with what people do. There I really
don't see that there's much going on. In other words, no one
seems to be proposing sort of radical interventions into the brain so
as to make people, you know, different or something like that. I mean,
Mike has shown that rather clearly.
So, that concern on my part has faded away. I just
don't see that there are ethical issues along those lines.
My second concern had to do more with questions in ethical
theory. Now, one of them was to what an extent progress in neurology
was driving us away from ethics and from the replies we heard today
from Professor Kagan, et cetera. I'm reassured that there's a
big gap there and that in no way are we giving up issues of freedom of
the will or that.
Now, the last thing about which I was concerned, and
it's connected to this, were issues connected with the presentation
by Professor Jonathan Cohen last time. I thought they were quite
fascinating, and I tried to think about them, not necessarily because
they were new. I think that the emotional reaction to certain kinds of
actions is known for a long time.
It became clear to me later on that his field is really a
field very different from ethics, in fact, because even if a PET scan
tells you what the reaction of certain agents are to certain kinds of
actions, that, unfortunately, does not tell us anything about whether
it's true that those actions are morally right or morally wrong.
That, in a way, put me to rest because it means that we are really in a
world of multiple dimensions in which we have to think about certain
domains in certain ways and about other domains in other ways.
So, in a way, I'm at peace, if I should say so, with
everything that I've heard right now. Now, that said, it seems to
me that Jim is pointing in a very promising direction. As far as I can
see, aging and connected with that the questions of justice related to
organ transplantation are really going to be pressing issues, and I
think issues that will demand public policy and therefore will demand
some kind of ethical advice.
CHAIRMAN KASS: Ben?
DR. CARSON: If, in fact, there is scientific evidence,
as was suggested this morning, that the intrauterine environment
can have a positive effect on the potential of a child, and if in
fact it is true that a caring and nurturing environment can improve
their subsequent intellectual performance, I guess an ethical question
becomes do we as a society have a responsibility to at least disseminate
this information in a wide fashion and try to facilitate both the
pre-natal and post-natal environments for all of our citizens.
CHAIRMAN KASS: Thank you. Peter, Michael, and Gil, and
then we will halt, just arbitrarily.
DR. LAWLER: I would like to agree with Jim Wilson that our
main focus probably should be on questions concerning an aging society,
but I'm not a scientist, but I do think science is a very high
human good, and I do want to become more rational.
With this in mind, I was really fascinated by the
presentations today. I agree with Alfonso. I'm at peace with
them. I don't see any lurking danger to anything that we need to
deal with immediately or anything like that. It does seem like in many
respects, neuroscience is in the early stages of development and so
forth, but it does seem to me it's really important.
One breakthrough I noticed in the materials we read and what we
heard is that basically behaviorism is dead. Basically in
a certain way, sociobiology is dead because we're now
getting solid scientific evidence that many of our distinctively
human qualities, like for example, language, have a natural
foundation, that they're innate in some sense.
So, it might be, from a theoretical point of view, good to
reflect on this, but I'm not quite sure what public policy
implications would derive from this, and it might be as interesting and
as futile as free will versus determinism finally.
Nonetheless, in my project to become more rational, if
someone could conceive a way of studying this with public policy
implications, I'd be all for it.
CHAIRMAN KASS: Michael Sandel?
PROFESSOR SANDEL: Well, Leon, after the lunch break, you
addressed some rumbling doubts around the table about the practical and
ethical public policy implications of the kinds of presentations we
were hearing today, and I for one was greatly heartened and relieved
when you tried to address those doubts by saying well, it would take us
back to Lucretius, these issues. We have an expansive executive order
that would encompass Lucretius, and that's good enough for me.
CHAIRMAN KASS: I said we were going to bracket the
Lucretian question, and we were going to learn something about the
science, but never mind.
DR. GEORGE: But we also heard about studies described as
classical studies from the 1970's.
PROFESSOR SANDEL: So, Lucretius would please me, but thinking
about what really will sustain a project for this council. I think
that in the neuroscience area, what worked, what was stimulating, what
educated us, and Alfonso says he's at peace now, which worries me
because I like Alfonso when he's agitated. That's what makes
things interesting. So, I would oppose any topic that would leave
Alfonso at peace.
I think that what agitated all of us and excited and
intrigued all of us about the neuroscience topic were the two
provocative presentations of Pinker and Cohen. That's what got
this group interested in neuroscience. The thing about brain imaging
and cognitive mapping and what were the implications for free will
versus mechanism and what were the implications for responsibility and
maybe ultimately for criminal responsibility. So, people got all
excited about that, and we were in a combat, some of us, with Pinker
and Cohen. That was interesting. That was the part of neuroscience
that seemed to be sort of rich with implications for ethics.
But as we delve into sort of the main lines of work and
research in these sessions today, it turns out that that's more, if
we're framing a project, it's not easy to frame a project
around the topics that excited us and interested us with the Pinker and
the Cohen. The mundane state of the discipline doesn't really lend
itself, I don't think, to a project that we can really usefully
So, my suggestion would be that we shouldn't take up
the neuroscience thing after all.
CHAIRMAN KASS: That we should not?
PROFESSOR SANDEL: Should not, and instead maybe the aging and
the elderly thing will have something useful. I would go back to
Jim's idea. Organ transplants not necessarily by itself is a topic
but is one way of getting at the broader question that we've toyed
with taking up before, the issue of commodification of the body, organ
transplants being one practical question that's looming on the
horizon that would enable us to take up the commodification question.
Listening to the presentations today, I think we'd be better off
with that than we would with the neuroscience.
CHAIRMAN KASS: Mike, did you want a quick comment to this?
DR. GAZZANIGA: Well, at the risk of being inconsistent.
So, let's take Jim's concern about aging, and let me raise a
question that neuroscience has a lot to speak about, death of the
person versus death of the brain. Now, that will get you all going.
There are many, many current brain imaging studies that
touch on what we know about the parts of the brain that are involved in
self and parts of the brain that have to be active in various states of
conscious experience and so forth and so on. The model is that right
now, Dr. Carson would know about this more than I do, that in
cardiology, the current cardiologist is faced very commonly now with
the ethical question, a patient comes in who has a pacemaker in them
and it's working fine and it's sustained their life, and now
other diseases have caught up with them, and they want the pacemaker
turned off. It's a tough decision.
Some doctors won't turn it off, some will. They want
it reprogrammed. They want to check out. They've had enough.
It's easy to imagine down the pike that they're
going to be—there's already deep brain stimulators that have this
wonderful effect on some Parkinson's cases. There could be similar
critical implants in the brain that are life sustaining, and then the
question is if other things catch up with the patient, some form of
cancer, heart disease, and if it's the brain, does the medical
community have the right to turn this off after they've turned it
on, and how do you think through that moral issue.
So, one could get back into it real quickly.
PROFESSOR SANDEL: Then that would be one subset under the
general heading of end of life issues, which would be fine. That
wouldn't be neuroscience as a broad category as we've been
thinking of it here.
CHAIRMAN KASS: Gil, please?
PROFESSOR MEILAENDER: My first and last view on this is also
doubt whether I really see a way forward for us. Having said that, I
mean, I do think there is a project here. I just don't know
whether we're the people to do it, or we're up for it.
I think that what Professor Spelke gave us this afternoon
was in some ways a bunch of empirical evidence in support of what, if
I'm remembering correctly, Kant called something like the
transcendental unity of apperception. So, there are profound questions
about the relation between behavior and biology that were raised here,
and questions, Alfonso, that aren't so clear to me.
In other words, if there are structures that are really
given, what does that—does that have any implications for morality or
not? I mean, there are very deep questions that could be raised there,
and I think we could do something interesting, or someone could do
something interesting on that.
It would not be the kind of project that had immediate public
policy implications. It would be more like Beyond Therapy
in the sense that it would simply seek to educate the public
about some very deep issues which are never going to go away,
which are very old and are just raised in different contexts
now but are still always worth thinking about.
So, I would have no objection in doing that. I think it
could be very useful and provocative in various ways. Having said all
that, I'm not sure I see a way forward for us to do it or whether
we're the body that's up to it in a way.
So, I do want to go on record as saying I think there's
a serious project actually here of deep philosophical import, but
I'm not confident that it's wise for us to really try it.
CHAIRMAN KASS: Good. Let me make a procedural suggestion
here. Speaking simply for myself, I'm not ready to toss in the
towel on this, partly because, as I said at the beginning of the day,
the background here today, the purpose of the day was to give us some
fundamental background and to see whether on the basis of this
foundation we could then develop the kind of project that would suit
this body, focused with some kind of practical implications, not
without some theoretical or deep human significance, but not to have a
simply philosophical project like "Beyond Therapy." I would
agree with Gil. That's not for this group.
There were topics tossed out before about neural imaging,
its promise, its perils. However primitive it is, people are making
use of it for all kinds of purposes, and we could do a service simply
to call attention to how much is known and what the possible misuses or
good uses of that would be. That would be one thing.
There are other people who are talking about the re-emergence
of deep brain stimulation and various other kinds of interventions
in which the question is not whether you just turned the machine
off, but what actually does this mean for questions of autonomy
and control and the like. We could begin to at least explore some
of the sub-areas, both of a technical sort that does raise ethical
and social questions. It's not for today.
What this discussion shows me at least is that if this
project is to go forward, I and the staff have to do some hard work
with your advice, to put together a working paper to try to focus this
somewhat before we bring anything back to you for the next meeting, and
we'll take that as our assignment, mindful of the fact that
there's at least some skepticism around the table as to whether
there is a clear enough focus in this neuroscience area.
The importance of this stuff is, I think, clear.
There's no sense that there's anything ominous here about which
we have to go ring the alarm bell, but this is science coming home to
work on certain fundamental things of our humanity, and we would be
foolish, I think, if we simply turned away our eye, especially when no
one else has bothered to take it up, and neuroethics is a growing
field, and the train shouldn't leave the station without our at
least paying some attention as to whether there's something here
ripe for our attention—weighty, ripe, and doable.
We have to go to an ethics class across the hall in the
break room. Someone is waiting for us there. The formal session is
adjourned until tomorrow morning, 8:30 we will convene. I'm happy
to say that our colleague, Bill May, will be with us. He is the senior
consultant on this aging project, and will be joining us at the table.
(Whereupon, the above-referenced matter was
adjourned at 5:23 p.m., to reconvene the next day at 8:30 a.m.)