[Paleopsych] Edge 160: The Science of Gender and Science: Pinker vs. Spelke: A Debate

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The Science of Gender and Science: Pinker vs. Spelke: A Debate
Edge 160-- May 10, 2005 (21.150 words)

     ...on the research on mind, brain, and behavior that may be relevant
    to gender disparities in the sciences, including the studies of bias,
     discrimination and innate and acquired difference between the sexes.
             Harvard University o Mind/Brain/Behavior Initiative

[After this is a profile of John Brockman, then Linda S. Gottfredson responding 
to Simon Baron-Cohen, and some Edge books.]

             Harvard University o Mind/Brain/Behavior Initiative

    The Mind Brain and Behavior Inter-Faculty Initiative (MBB), under the
    leadership of Co-Directors Marc D. Hauser and Elizabeth Spelke, is a
    university-wide community that studies the structure, function,
    evolution, development, and pathology of the nervous system, in
    relation to decision-making and behavior.


    On April 22, 2005, Harvard University's Mind/Brain/Behavior Initiative
    (MBB) held a defining debate on the public discussion that began on
    January 16th with the public comments by Lawrence Summers, president
    of Harvard, on sex differences between men and women and how they may
    relate to the careers of women in science. The debate at MBB, "The
    Gender of Gender and Science" was "on the research on mind, brain, and
    behavior that may be relevant to gender disparities in the sciences,
    including the studies of bias, discrimination and innate and acquired
    difference between the sexes".

    It's interesting to note that since the controversy surrounding
    Summers' remarks began, there has been an astonishing absence of
    discussion of the relevant science...you won't find it in the hundreds
    and hundreds of articles in major newspapers; nor will find it in the
    Harvard faculty meetings where the president of the leading University
    in America was indicted for presenting controversial ideas.

    Scientists debate continually, and reality is the check. They may have
    egos as large as those possessed by the iconic figures of the academic
    humanities, but they handle their hubris in a very different way. They
    can be moved by arguments, because they work in an empirical world of
    facts, a world based on reality. There are no fixed, unalterable
    positions. They are both the creators and the critics of their shared
    enterprise. Ideas come from them and they also criticize one another's

    Through the process of creativity and criticism and debates, they
    decide which ideas get weeded out and which become part of the
    consensus that leads to the next level of discovery.

    But unlike just about anything else said about Summers' remarks, the
    debate, "The Science of Gender and Science", between Harvard
    psychology professors Steven Pinker and Elizabeth Spelke, focused on
    the relevant scientific literature. It was both interesting on facts
    but differing in interpretation.

    Both presented scientific evidence with the realization and
    understanding that there was nothing obvious about how the data was to
    be interpreted. Their sharp scientific debate informed rather than
    detracted. And it showed how a leading University can still fulfill
    its role of providing a forum for free and open discussion on
    controversial subjects in a fair-minded way. It also had the added
    benefit that the participants knew what they were talking about.

    Who won the debate? Make up your own mind. Watch the video, listen to
    the audio, read the text and check out the slide presentations.

    There's a lesson here: let's get it right and when we do we will
    adjust our attitudes. That's what science can do, and that's what Edge
    offers by presenting Pinker vs. Spelke to a wide public audience.

    [18]--John Brookman's biography

    STEVEN PINKER is the Johnstone Family Professor in the Department of
    Psychology at Harvard University. His research has won prizes from the
    National Academy of Sciences and the Royal Institution of Great
    Britain, and he is the author of six books, including The Language
    Instinct, How the Mind Works, Words and Rules, and The Blank Slate.

    [19]Steven Pinker's Edge Bio Page

    ELIZABETH S. SPELKE is Berkman Professor of Psychology at Harvard
    University, where she is Co-Director of the Mind, Brain, and Behavior
    Initiative. A member of the National Academy of Sciences and the
    American Academy of Arts and Sciences, she is cited by Time Magazine
    as one of America's Best in Science and Medicine.

    [20]Elizabeth Spelke's Edge Bio Page

    [EDITOR'S NOTE: Pinker and Spelke each made presentations of about 40
    minutes, without interruption, from each other or from the audience.
    They then responded to each other's presentations. By mutual
    agreement, Pinker made the first presentation.

    This Edge presentation includes: the transcribed text; streaming audio
    of the full debate; 6-minute video clips from Pinker and Spelke's
    opening statements; a 20-minute video clip of the their closing
    discussion; and online versions of the speakers' slide presentations.
    There are two options for viewing the slides: Clicking on the links
    immediately below brings up the file of either Pinker or Spelke's
    complete slide presentation. Or, the individual slides are also
    included for reference as expandable thumbnails in the margin of the

                               [21]PINKER slide

                       [bracket_r.gif] [bracket_l.gif]

                               [22]SPELKE slide

                    [banner.audio.gif] [banner.video.gif]

                      [headphonelogo.gif] Steven Pinker
                                 [40 minutes]
                             [23]Streaming Audio

                     [headphonelogo.gif] Elizabeth Spelke
                                 [45 minutes]
                             [24]Streaming Audio

                  [headphonelogo.gif] Concluding Discussion
                                 [20 minutes]
                             [25]Streaming Audio

      [26][qtsmall.gif] Steven Pinker: Opening Remarks [6 minute video]
                          [27]Broadband | [28]Modem

     [29][qtsmall.gif] Elizabeth Spelke: Opening Remarks [6 minute video]
                          [30]Broadband | [31]Modem

        [32][qtsmall.gif] Steven Pinker & Elizabeth Spelke: Concluding
                         Discussion [20 minute video]
                        [33]Broadband | [34]Modem


    The complete video is also available for download through Harvard's
    MBB website ([37]click here).

                                Steven Pinker

     (STEVEN PINKER:) Thanks, Liz, for agreeing to this exchange. It's a
    privilege to be engaged in a conversation with Elizabeth Spelke. We go
       back a long way. We have been colleagues at MIT, where I helped
    attract her, and at Harvard, where she helped to attract me. With the
    rest of my field, I have enormous admiration for Elizabeth's brilliant
    contributions to our understanding of the origins of cognition. But we
       do find ourselves with different perspectives on a recent issue.

    [38][pinker_Page_01.jpg] [These are Steve's Power Point pages.]

    For those of you who just arrived from Mars, there has been a certain
    amount of discussion here at Harvard on a particular datum, namely the
      under-representation of women among tenure-track faculty in elite
    universities in physical science, math, and engineering. Here are some
                               recent numbers:

       As with many issues in psychology, there are three broad ways to
    explain this phenomenon. One can imagine an extreme "nature" position:
    that males but not females have the talents and temperaments necessary
    for science. Needless to say, only a madman could take that view. The
              extreme nature position has no serious proponents.

      There is an extreme "nurture" position: that males and females are
     biologically indistinguishable, and all relevant sex differences are
                     products of socialization and bias.

    Then there are various intermediate positions: that the difference is
     explainable by some combination of biological differences in average
      temperaments and talents interacting with socialization and bias.

    Liz has embraced the extreme nurture position. There is an irony here,
    because in most discussions in cognitive science she and I are put in
    the same camp, namely the "innatists," when it comes to explaining the
      mind. But in this case Liz has said that there is "not a shred of
    evidence" for the biological factor, that "the evidence against there
    being an advantage for males in intrinsic aptitude is so overwhelming
    that it is hard for me to see how one can make a case at this point on
    the other side," and that "it seems to me as conclusive as any finding
                            I know of in science."

    Well we certainly aren't seeing the stereotypical gender difference in
        confidence here! Now, I'm a controversial guy. I've taken many
       controversial positions over the years, and, as a member of Homo
    sapiens, I think I am right on all of them. But I don't think that in
      any of them I would say there is "not a shred of evidence" for the
    other side, even if I think that the evidence favors one side. I would
        not say that the other side "can't even make a case" for their
    position, even if I think that their case is not as good as the one I
      favor. And as for saying that a position is "as conclusive as any
    finding in science" -- well, we're talking about social science here!
    This statement would imply that the extreme nurture position on gender
    differences is more conclusive than, say the evidence that the sun is
    at the center of the solar system, for the laws of thermodynamics, for
           the theory of evolution, for plate tectonics, and so on.

     These are extreme statements -- especially in light of the fact that
      an enormous amount of research, summarized in these and many other
      literature reviews, in fact points to a very different conclusion.
        I'll quote from one of them, a book called Sex Differences in
     Cognitive Ability by Diane Halpern. She is a respected psychologist,
         recently elected as president of the American Psychological
     Association, and someone with no theoretical axe to grind. She does
      not subscribe to any particular theory, and has been a critic, for
     example, of evolutionary psychology. And here what she wrote in the
                             preface to her book:

      "At the time I started writing this book it seemed clear to me that
      any between sex differences in thinking abilities were due to
      socialization practices, artifacts, and mistakes in the research.
      After reviewing a pile of journal articles that stood several feet
      high, and numerous books and book chapters that dwarfed the stack
      of journal articles, I changed my mind. The literature on sex
      differences in cognitive abilities is filled with inconsistent
      findings, contradictory theories, and emotional claims that are
      unsupported by the research. Yet despite all the noise in the data,
      clear and consistent messages could be heard. There are real and in
      some cases sizable sex differences with respect to some cognitive
      abilities. Socialization practices are undoubtedly important, but
      there is also good evidence that biological sex differences play a
      role in establishing and maintaining cognitive sex differences, a
      conclusion I wasn't prepared to make when I began reviewing the
      relevant literature."


                    This captures my assessment perfectly.

     Again for the benefit of the Martians in this room: This isn't just
      any old issue in empirical psychology. There are obvious political
       colorings to it, and I want to begin with a confession of my own
     politics. I am a feminist. I believe that women have been oppressed,
    discriminated against, and harassed for thousands of years. I believe
     that the two waves of the feminist movement in the 20th century are
    among the proudest achievements of our species, and I am proud to have
       lived through one of them, including the effort to increase the
                   representation of women in the sciences.

      But it is crucial to distinguish the moral proposition that people
    should not be discriminated against on account of their sex -- which I
    take to be the core of feminism -- and the empirical claim that males
    and females are biologically indistinguishable. They are not the same
    thing. Indeed, distinguishing them is essential to protecting the core
    of feminism. Anyone who takes an honest interest in science has to be
     prepared for the facts on a given issue to come out either way. And
       that makes it essential that we not hold the ideals of feminism
     hostage to the latest findings from the lab or field. Otherwise, if
     the findings come out as showing a sex difference, one would either
    have to say, "I guess sex discrimination wasn't so bad after all," or
    else furiously suppress or distort the findings so as to preserve the
    ideal. The truth cannot be sexist. Whatever the facts turn out to be,
         they should not be taken to compromise the core of feminism.

       Why study sex differences? Believe me, being the Bobby Riggs of
      cognitive science is not my idea of a good time. So should I care
        about them, especially since they are not the focus of my own

    First, differences between the sexes are part of the human condition.
    We all have a mother and a father. Most of us are attracted to members
      of the opposite sex, and the rest of us notice the difference from
     those who do. And we can't help but notice the sex of our children,
            friends, and our colleagues, in every aspect of life.

      Also, the topic of possible sex differences is of great scientific
        interest. Sex is a fundamental problem in biology, and sexual
     reproduction and sex differences go back a billion years. There's an
    interesting theory, which I won't have time to explain, which predicts
    that there should be an overall equal investment of organisms in their
        sons and daughters; neither sex is predicted to be superior or
    inferior across the board. There is also an elegant theory, namely Bob
       Trivers' theory of differential parental investment, which makes
         highly specific predictions about when you should expect sex
                 differences and what they should look like.


        The nature and source of sex differences are also of practical
      importance. Most of us agree that there are aspects of the world,
     including gender disparities, that we want to change. But if we want
      to change the world we must first understand it, and that includes
                understanding the sources of sex differences.

     Let's get back to the datum to be explained. In many ways this is an
      exotic phenomenon. It involves biologically unprepared talents and
     temperaments: evolution certainly did not shape any part of the mind
     to do the work of a professor of mechanical engineering at MIT, for
     example. The datum has nothing to do with basic cognitive processes,
    or with those we use in our everyday lives, in school, or even in most
         college courses, where indeed there are few sex differences.

    Also, we are talking about extremes of achievement. Most women are not
      qualified to be math professors at Harvard because most men aren't
    qualified to be math professors at Harvard. These are extremes in the

           And we're talking about a subset of fields. Women are no
     under-represented to nearly the same extent in all academic fields,
              and certainly not in all prestigious professions.

      Finally, we are talking about a statistical effect. This is such a
           crucial point that I have to discuss it in some detail.

     Women are nowhere near absent even from the field in which they are
     most under-represented. The explanations for sex differences must be
         statistical as well. And here is a touchstone for the entire

    These are two Gaussian or normal distributions; two bell curves. The X
    axis stands for any ability you want to measure. The Yaxis stands for
     the proportion of people having that ability. The overlapping curves
      are what you get whenever you compare the sexes on any measure in
     which they differ. In this example, if we say that this is the male
    curve and this is the female curve, the means may be different, but at
    any particular ability level there are always representatives of both

     So right away a number of public statements that have been made last
     couple of months can be seen as red herrings, and should never have
        been made by anyone who understands the nature of statistical
      distributions. This includes the accusation that President Summers
     implied that "50% of the brightest minds in America do not have the
     right aptitude for science," that "women just can't cut it," and so
    on. These statements are statistically illiterate, and have nothing to
                   do with the phenomena we are discussing.

    There are some important corollaries of having two overlapping normal
     distributions. One is that a normal distribution falls off according
      to the negative exponential of the square of the distance from the
     mean. That means that even when there is only a small difference in
    the means of two distributions, the more extreme a score, the greater
      the disparity there will be in the two kinds of individuals having
     such a score. That is, the ratios get more extreme as you go farther
     out along the tail. If we hold a magnifying glass to the tail of the
    distribution, we see that even though the distributions overlap in the
     bulk of the curves, when you get out to the extremes the difference
                between the two curves gets larger and larger.

      For example, it's obvious that distributions of height for men and
      women overlap: it's not the case that all men are taller than all
       women. But while at five foot ten there are thirty men for every
     woman, at six feet there are two thousand men for every woman. Now,
       sex differences in cognition tend not to be so extreme, but the
                     statistical phenomenon is the same.
      [56][pinker_Page_19.jpg] A second important corollary is that tail
     ratios are affected by differences in variance. And biologists since
    Darwin have noted that for many traits and many species, males are the
     more variable gender. So even in cases where the mean for women and
      the mean for men are the same, the fact that men are more variable
     implies that the proportion of men would be higher at one tail, and
         also higher at the other. As it's sometimes summarized: more
                           prodigies, more idiots.

     With these statistical points in mind, let me begin the substance of
    my presentation by connecting the political issue with the scientific
    one. Economists who study patterns of discrimination have long argued
    (generally to no avail) that there is a crucial conceptual difference
     between difference and discrimination. A departure from a 50-50 sex
    ratio in any profession does not, by itself, imply that we are seeing
     discrimination, unless the interests and aptitudes of the two groups
     are equated. Let me illustrate the point with an example, involving

     I work in a scientific field -- the study of language acquisition in
     children -- that is in fact dominated by women. Seventy-five percent
    of the members the main professional association are female, as are a
     majority of the keynote speakers at our main conference. I'm here to
      tell you that it's not because men like me have been discriminated
    against. I decided to study language development, as opposed to, say,
      mechanical engineering, for many reasons. The goal of designing a
    better automobile transmission does not turn me on as much as the goal
    of figuring out how kids acquire language. And I don't think I'd be as
     good at designing a transmission as I am in studying child language.

    Now, all we need to do to explain sex differences without invoking the
      discrimination or invidious sexist comparisons is to suppose that
       whatever traits I have that predispose me to choose (say) child
      language over (say) mechanical engineering are not exactly equally
     distributed statistically among men and women. For those of you out
     there -- of either gender -- who also are not mechanical engineers,
                you should understand what I'm talking about.
       [58][pinker_Page_21.jpg] Okay, so what are the similarities and
    differences between the sexes? There certainly are many similarities.
     Men and women show no differences in general intelligence or g -- on
    average, they are exactly the same, right on the money. Also, when it
      comes to the basic categories of cognition -- how we negotiate the
       world and live our lives; our concept of objects, of numbers, of
       people, of living things, and so on -- there are no differences.

       Indeed, in cases where there are differences, there are as many
    instances in which women do slightly better than men as ones in which
      men do slightly better than women. For example, men are better at
      throwing, but women are more dexterous. Men are better at mentally
    rotating shapes; women are better at visual memory. Men are better at
        mathematical problem-solving; women are better at mathematical
                           calculation. And so on.

    But there are at least six differences that are relevant to the datum
      we have been discussing. The literature on these differences is so
     enormous that I can only touch on a fraction of it. I'll restrict my
    discussion to a few examples in which there are enormous data sets, or
             there are meta-analyses that boil down a literature.

      The first difference, long noted by economists studying employment
     practices, is that men and women differ in what they state are their
    priorities in life. To sum it up: men, on average, are more likely to
       chase status at the expense of their families; women give a more
     balanced weighting. Once again: Think statistics! The finding is not
      that women value family and don't value status. It is not that men
     value status and don't value family. Nor does the finding imply that
    every last woman has the asymmetry that women show on average or that
      every last man has the asymmetry that men show on average. But in
           large data sets, on average, an asymmetry what you find.
    [61][pinker_Page_24.jpg] Just one example. In a famous long-term study
    of mathematically precocious youth, 1,975 youngsters were selected in
    7th grade for being in the top 1% of ability in mathematics, and then
        followed up for more than two decades. These men and women are
    certainly equally talented.  And if anyone has ever been encouraged in
      math and science, these kids were. Both genders: they are equal in
     their levels of achievement, and they report being equally satisfied
      with the course of their lives. Nonetheless there are statistical
      differences in what they say is important to them. There are some
     things in life that the females rated higher than males, such as the
     ability to have a part-time career for a limited time in one's life;
     living close to parents and relatives; having a meaningful spiritual
    life; and having strong friendships. And there are some things in life
    that the males rated higher than the females. They include having lots
    of money; inventing or creating something; having a full-time career;
      and being successful in one's line of work. It's worth noting that
     studies of highly successful people find that single-mindedness and
      competitiveness are recurring traits in geniuses (of both sexes).
    [62][pinker_Page_25.jpg] Here is one other figure from this data set.
    As you might expect, this sample has a lot of people who like to work
    Herculean hours. Many people in this group say they would like to work
     50, 60, even 70 hours a week. But there are also slight differences.
    At each one of these high numbers of hours there are slightly more men
     than women who want to work that much. That is, more men than women
                  don't care about whether they have a life.
    [63][pinker_Page_26.jpg] Second, interest in people versus things and
     abstract rule systems. There is a staggering amount of data on this
        trait, because there is an entire field that studies people's
    vocational interests. I bet most of the people in this room have taken
      a vocational interest test at some point in their lives. And this
      field has documented that there are consistent differences in the
    kinds of activities that appeal to men and women in their ideal jobs.
     I'll just discuss one of them: the desire to work with people versus
    things. There is an enormous average difference between women and men
               in this dimension, about one standard deviation.

        And this difference in interests will tend to cause people to
    gravitate in slightly different directions in their choice of career.
     The occupation that fits best with the "people" end of the continuum
     is "director of a community services organization." The occupations
         that fit best with the "things" end are physicist, chemist,
              mathematician, computer programmer, and biologist.

     We see this consequence not only in the choice of whether to go into
    science, but also in the choice which branch of science the two sexes
     tend to go into. Needless to say, from 1970 to 2002 there was a huge
    increase in the percentage of university degrees awarded to women. But
      the percentage still differs dramatically across fields. Among the
    Ph.Ds awarded in 2001, for example, in education 65% of the doctorates
    went to women; in the social sciences, 54%; in the life sciences, 47%;
    in the physical sciences, 26%; in engineering, 17%. This is completely
    predictable from the difference in interests between people and living
    things, on the one hand, and inanimate objects, on the other. And the
     pattern is pretty much the same in 1980 and 2001, despite the change
                             in absolute numbers.
    [66][pinker_Page_29.jpg] Third, risk. Men are by far the more reckless
       sex. In a large meta-analysis involving 150 studies and 100,000
      participants, in 14 out of 16 categories of risk-taking, men were
    over-represented. The two sexes were equally represented in the other
    two categories, one of which was smoking, for obvious reasons. And two
    of the largest sex differences were in "intellectual risk taking" and
     "participation in a risky experiment." We see this sex difference in
     everyday life, in particular, in the following category: the Darwin
      Awards, "commemorating those individuals who ensure the long-term
    survival of our species by removing themselves from the gene pool in a
      sublimely idiotic fashion." Virtually all -- perhaps all -- of the
                               winners are men.
          [68][pinker_Page_31.jpg] Fourth, three-dimensional mental
    transformations: the ability to determine whether the drawings in each
     of these pairs the same 3-dimensional shape. Again I'll appeal to a
    meta-analysis, this one containing 286 data sets and 100,000 subjects.
     The authors conclude, "we have specified a number of tests that show
      highly significant sex differences that are stable across age, at
    least after puberty, and have not decreased in recent years." Now, as
    I mentioned, for some kinds of spatial ability, the advantage goes to
      women, but in "mental rotation,"spatial perception," and "spatial
                  visualization" the advantage goes to men.
        [70][pinker_Page_33.jpg] Now, does this have any relevance to
       scientific achievement? We don't know for sure, but there's some
            reason to think that it does. In psychometric studies,
          three-dimensional spatial visualization is correlated with
     mathematical problem-solving. And mental manipulation of objects in
    three dimensions figures prominently in the memoirs and introspections
    of most creative physicists and chemists, including Faraday, Maxwell,
    Tesla, Kéekulé, and Lawrence, all of whom claim to have hit upon their
    discoveries by dynamic visual imagery and only later set them down in
      equations. A typical introspection is the following: "The cyclical
      entities which seem to serve as elements in my thought are certain
         signs and more or less clear images which can be voluntarily
        reproduced and combined. This combinatory play seems to be the
    essential feature in productive thought before there is any connection
    with logical construction in words or other kinds of signs." The quote
                 comes from this fairly well-known physicist.
      [74][pinker_Page_37.jpg] Fifth, mathematical reasoning. Girls and
        women get better school grades in mathematics and pretty much
       everything else these days. And women are better at mathematical
     calculation. But consistently, men score better on mathematical word
          problems and on tests of mathematical reasoning, at least
    statistically. Again, here is a meta analysis, with 254 data sets and
     3 million subjects. It shows no significant difference in childhood;
    this is a difference that emerges around puberty, like many secondary
         sexual characteristics. But there are sizable differences in
    adolescence and adulthood, especially in high-end samples. Here is an
      example of the average SAT mathematical scores, showing a 40-point
    difference in favor of men that's pretty much consistent from 1972 to
     1997. In the Study of Mathematically Precocious Youth (in which 7th
    graders were given the SAT, which of course ordinarily is administered
     only to older, college-bound kids), the ratio of those scoring over
    700 is 2.8 to 1 male to female. (Admittedly, and interestingly, that's
    down from 25 years ago, when the ratio was 13-to1, and perhaps we can
    discuss some of the reasons.) At the 760 cutoff, the ratio nowadays is
                             7 males to 1 female.
     [75][pinker_Page_38.jpg] Now why is there a discrepancy with grades?
          Do SATs and other tests of mathematical reasoning aptitude
     underpredict grades, or do grades overpredict high-end aptitude? At
    the Radical Forum Liz was completely explicit in which side she takes,
      saying that "the tests are no good," unquote. But if the tests are
     really so useless, why does every major graduate program in science
    still use them -- including the very departments at Harvard and MIT in
           which Liz and I have selected our own graduate students?

    I think the reason is that school grades are affected by homework and
     by the ability to solve the kinds of problems that have already been
      presented in lecture and textbooks. Whereas the aptitude tests are
        designed to test the application of mathematical knowledge to
     unfamiliar problems. And this, of course, is closer to the way that
               math is used in actually doing math and science.

           Indeed, contrary to Liz, and the popular opinion of many
     intellectuals, the tests are surprisingly good. There is an enormous
    amount of data on the predictive power of the SAT. For example, people
    in science careers overwhelmingly scored in 90th percentile in the SAT
    or GRE math test. And the tests predict earnings, occupational choice,
      doctoral degrees, the prestige of one's degree, the probability of
     having a tenure-track position, and the number of patents. Moreover
     this predictive power is the same for men and for women. As for why
    there is that underprediction of grades -- a slight under-prediction,
     one-tenth of a standard deviation -- the Educational Testing Service
     did a study on that phenomenon, and were able to explain the mystery
      by a combination of the choice of major, which differs between the
              sexes, and the greater conscientiousness of women.
    Finally there's a sex difference in variability. It's crucial here to
    look at the right samples. Estimates of variance depend highly on the
    tails of the distribution, which by definition contain smaller numbers
       of people. Since people at the tails of the distribution in many
        surveys are likely to be weeded out for various reasons, it's
         important to have large representative samples from national
    populations. In this regard the gold standard is the Science paper by
      Novell and Hedges, which reported six large stratified probability
     samples. They found that in 35 out of 37 tests, including all of the
    tests in math, space, and science, the male variance was greater than
                             the female variance.
    [78][pinker_Page_41.jpg] One other data set meeting the gold standard
    is displayed in this graph, showing the entire population of Scotland,
        who all took an intelligence test in a single year. The X axis
      represents IQ, where the mean is 100, and the Yaxis represents the
      proportion of men versus women. As you can see these are extremely
    orderly data. In the middle part of the range, females predominate; at
    both extremes, males slightly predominate. Needless to say, there is a
     large percentage of women at both ends of the scale -- but there is
                          also large sex difference.
         [79][pinker_Page_42.jpg] Now the fact that these six gender
     differences exist does not mean that they are innate. This of course
      is a much more difficult issue to resolve. A necessary preamble to
    this discussion is that nature and nurture are not alternatives; it is
    possible that the explanation for a given sex difference involves some
      of each. The only issue is whether the contribution of biology is
     greater than zero. I think that there are ten kinds of evidence that
    the contribution of biology is greater than zero, though of course it
                         is nowhere near 100 percent.

     [81][pinker_Page_44.jpg] First, there are many biological mechanisms
      by which a sex difference could occur. There are large differences
       between males and females in levels of sex hormones, especially
    prenatally, in the first six months of life, and in adolescence. There
    are receptors for hormones all over the brain, including the cerebral
    cortex. There are many small differences in men's and women's brains,
      including the overall size of the brain (even correcting for body
        size), the density of cortical neurons, the degree of cortical
       asymmetry, the size of hypothalamic nuclei, and several others.


     Second, many of the major sex differences -- certainly some of them,
    maybe all of them, are universal. The idea that there are cultures out
     there somewhere in which everything is the reverse of here turns out
        to be an academic legend. In his survey of the anthropological
     literature called Human Universals, the anthropologist Donald Brown
       points out that in all cultures men and women are seen as having
      different natures; that there is a greater involvement of women in
     direct child care; more competitiveness in various measures for men
     than for women; and a greater spatial range traveled by men compared
                                 to by women.

        In personality, we have a cross-national survey (if not a true
      cross-cultural one) in Feingold's meta-analysis, which noted that
    gender differences in personality are consistent across ages, years of
      data collection, educational levels, and nations. When it comes to
        spatial manipulation and mathematical reasoning, we have fewer
    relevant data, and we honestly don't have true cross-cultural surveys,
       but we do have cross-national surveys. David Geary and Catherine
      Desoto found the expected sex difference in mental rotation in ten
     European countries and in Ghana, Turkey, and China. Similarly, Diane
    Halpern, analyzing results from ten countries, said that "the majority
    of the findings show amazing cross-cultural consistency when comparing
                    males and females on cognitive tests."
     [83][pinker_Page_46.jpg] Third, stability over time. Surveys of life
     interests and personality have shown little or no change in the two
     generations that have come of age since the second wave of feminism.
    There is also, famously, resistance to change in communities that, for
       various ideological reasons, were dedicated to stamping out sex
     differences, and found they were unable to do so. These include the
    Israeli kibbutz, various American Utopian communes a century ago, and
                  contemporary androgynous academic couples.


    In tests of mental rotation, the meta-analysis by Voyer et al found no
     change over time. In mathematical reasoning there has been a decline
         in the size of the difference, although it has certainly not

    Fourth, many sex differences can be seen in other mammals. It would be
       an amazing coincidence if these differences just happened to be
    replicated in the arbitrary choices made by human cultures at the dawn
    of time. There are large differences between males and females in many
    mammals in aggression, in investment in offspring, in play aggression
     play versus play parenting, and in the range size, which predicts a
       species' sex differences in spatial ability (such as in solving
    mazes), at least in polygynous species, which is how the human species
      is classified. Many primate species even show a sex difference in
     their interest in physical objects versus conspecifics, a difference
     seen their patterns of juvenile play. Among baby vervet monkeys, the
    males even prefer to play with trucks and the females with other kinds
                                   of toys!

    Fifth, many of these differences emerge in early childhood. It is said
    that there is a technical term for people who believe that little boys
    and little girls are born indistinguishable and are molded into their
         natures by parental socialization. The term is "childless."

     Some sex differences seem to emerge even in the first week of life.
      Girls respond more to sounds of distress, and girls make more eye
    contact than boys. And in a study that I know Liz disputes and that I
     hope we'll talk about, newborn boys were shown to be more interested
      in looking at a physical object than a face, whereas newborn girls
    were shown to be more interested in looking at a face than a physical

       A bit later in development there are vast and robust differences
     between boys and girls, seen all over the world. Boys far more often
    than girls engage in rough-and-tumble play, which involves aggression,
     physical activity, and competition. Girls spend a lot more often in
    cooperative play. Girls engage much more often in play parenting. And
    yes, boys the world over turn anything into a vehicle or a weapon, and
        girls turn anything into a doll. There are sex differences in
        intuitive psychology, that is, how well children can read one
     another's minds. For instance, several large studies show that girls
       are better than boys in solving the "false belief task," and in
           interpreting the mental states of characters in stories.

     Sixth, genetic boys brought up as girls. In a famous 1970s incident
    called the John/Joan case, one member of a pair of identical twin boys
    lost his penis in a botched circumcision (I was relieved to learn that
      this was not done by a moyl, but by a bumbling surgeon). Following
    advice from the leading gender expert of the time, the parents agreed
    to have the boy castrated, given female-specific hormones, and brought
     up as a girl. All this was hidden from him throughout his childhood.

    When I was an undergraduate the case was taught to me as proof of how
     gender roles are socially acquired. But it turned out that the facts
    had been suppressed. When "Joan" and her family were interviewed years
        later, it turned out that from the youngest ages he exhibited
    boy-typical patterns of aggression and rough-and-tumble play, rejected
    girl-typical activities, and showed a greater interest in things than
     in people. At age 14, suffering from depression, his father finally
      told him the truth. He underwent further surgery, married a woman,
           adopted two children, and got a job in a slaughterhouse.

      This is not just a unique instance. In a condition called cloacal
        exstrophy, genetic boys are sometimes born without normal male
    genitalia. When they are castrated and brought up as girls, in 25 out
    of 25 documented instances they have felt that they were boys trapped
     in girls' bodies, and showed male-specific patterns of behavior such
                          as rough-and-tumble play.

      Seventh, a lack of differential treatment by parents and teachers.
       These conclusions come as a shock to many people. One comes from
       Lytton and Romney's meta-analysis of sex-specific socialization
     involving 172 studies and 28,000 children, in which they looked both
     at parents' reports and at direct observations of how parents treat
      their sons and daughters -- and found few or no differences among
    contemporary Americans. In particular, there was no difference in the
     categories "Encouraging Achievement" and "Encouraging Achievement in

         There is a widespread myth that teachers (who of course are
    disproportionately female) are dupes who perpetuate gender inequities
      by failing to call on girls in class, and who otherwise having low
     expectations of girls' performance. In fact Jussim and Eccles, in a
      study of 100 teachers and 1,800 students, concluded that teachers
     seemed to be basing their perceptions of students on those students'
                     actual performances and motivation.

      Eighth, studies of prenatal sex hormones: the mechanism that makes
       boys boys and girls girls in the first place. There is evidence,
      admittedly squishy in parts, that differences in prenatal hormones
     make a difference in later thought and behavior even within a given
    sex. In the condition called congenital adrenal hyperplasia, girls in
       utero are subjected to an increased dose of androgens, which is
    neutralized postnatally. But when they grow up they have male-typical
        toy preferences -- trucks and guns -- compared to other girls,
            male-typical play patterns, more competitiveness, less
     cooperativeness, and male-typical occupational preferences. However,
      research on their spatial abilities is inconclusive, and I cannot
     honestly say that there are replicable demonstrations that CAH women
               have male-typical patterns of spatial cognition.
    [90][pinker_Page_53.jpg] Similarly, variations in fetal testosterone,
    studied in various ways, show that fetal testosterone has a nonmonotic
    relationship to reduced eye contact and face perception at 12 months,
       to reduced vocabulary at 18 months, to reduced social skills and
     greater narrowness of interest at 48 months, and to enhanced mental
                 rotation abilities in the school-age years.

    [91][pinker_Page_54.jpg] Ninth, circulating sex hormones. I'm going to
      go over this slide pretty quickly because the literature is a bit
    messy. Though it's possible that all claims of the effects of hormones
     on cognition will turn out to be bogus, I suspect something will be
     salvaged from this somewhat contradictory literature. There are, in
        any case, many studies showing that testosterone levels in the
    low-normal male range are associated with better abilities in spatial
       manipulation. And in a variety of studies in which estrogens are
     compared or manipulated, there is evidence, admittedly disputed, for
        statistical changes in the strengths and weaknesses in women's
     cognition during the menstrual cycle, possibly a counterpart to the
     changes in men's abilities during their daily and seasonal cycles of
        [92][pinker_Page_55.jpg] My last kind of evidence: imprinted X
     chromosomes. In the past fifteen years an entirely separate genetic
    system capable of implementing sex differences has been discovered. In
     the phenomenon called genetic imprinting, studied by David Haig and
    others, a chromosome such as the X chromosome can be altered depending
     on whether it was passed on from one's mother or from one's father.
     This makes a difference in the condition called Turner syndrome, in
     which a child has just one X chromosome, but can get it either from
     her mother or her father. When she inherits an X that is specific to
       girls, on average she has a better vocabulary and better social
     skills, and is better at reading emotions, at reading body language,
                            and at reading faces.


                A remark on stereotypes, and then I'll finish.

     Are these stereotypes? Yes, many of them are (although, I must add,
    not all of them -- for example, women's superiority in spatial memory
         and mathematical calculation. There seems to be a widespread
      assumption that if a sex difference conforms to a stereotype, the
     difference must have been caused by the stereotype, via differential
     expectations for boys and for girls. But of course the causal arrow
     could go in either direction: stereotypes might reflect differences
      rather than cause them. In fact there's an enormous literature in
      cognitive psychology which says that people can be good intuitive
     statisticians when forming categories and that their prototypes for
    conceptual categories track the statistics of the natural world pretty
     well. For example, there is a stereotype that basketball players are
    taller on average than jockeys. But that does not mean that basketball
    players grow tall, and jockeys shrink, because we expect them to have
      certain heights! Likewise, Alice Eagly and Jussim and Eccles have
      shown that most of people's gender stereotypes are in fact pretty
        accurate. Indeed the error people make is in the direction of
                       underpredicting sex differences.
      [94][pinker_Page_57.jpg] To sum up: I think there is more than "a
         shred of evidence" for sex differences that are relevant to
      statistical gender disparities in elite hard science departments.
       There are reliable average difference in life priorities, in an
        interest in people versus things, in risk-seeking, in spatial
      transformations, in mathematical reasoning, and in variability in
         these traits. And there are ten kinds of evidence that these
     differences are not completely explained by socialization and bias,
                      although they surely are in part.

     [95][pinker_Page_58.jpg] A concluding remark. None of this provides
    grounds for ignoring the biases and barriers that do keep women out of
     science, as long as we keep in mind the distinction between fairness
     on the one hand and sameness on the other. And I will give the final
    word to Gloria Steinem: "there are very few jobs that actually require
      a penis or a vagina, and all the other jobs should be open to both

                               Elizabeth Spelke


[These are Liz's Power Point slides.]

    (ELIZABETH SPELKE:) Thanks, especially to Steve; I'm really glad we're
          able to have this debate, I've been looking forward to it.

    I want to start by talking about the points of agreement between Steve
     and me, and as he suggested, there are many. If we got away from the
    topic of sex and science, we'd be hard pressed to find issues that we
       disagree on. Here are a few of the points of agreement that are
       particularly relevant to the discussions of the last few months.

    First, we agree that both our society in general and our university in
    particular will be healthiest if all opinions can be put on the table
    and debated on their merits. We also agree that claims concerning sex
     differences are empirical, they should be evaluated by evidence, and
        we'll all be happier and live longer if we can undertake that
      evaluation as dispassionately and rationally as possible. We agree
    that the mind is not a blank slate; in fact one of the deepest things
       that Steve and I agree on is that there is such a thing as human
     nature, and it is a fascinating and exhilarating experience to study
       it. And finally, I think we agree that the role of scientists in
     society is rather modest. Scientists find things out. The much more
     difficult questions of how to use that information, live our lives,
    and structure our societies are not questions that science can answer.
              Those are questions that everybody must consider.

                           So where do we disagree?

    We disagree on the answer to the question, why in the world are women
       scarce as hens' teeth on Harvard's mathematics faculty and other
     similar institutions? In the current debate, two classes of factors
    have been said to account for this difference. In one class are social
         forces, including overt and covert discrimination and social
      influences that lead men and women to develop different skills and
    different priorities. In the other class are genetic differences that
      predispose men and women to have different capacities and to want
                              different things.

       In his book, The Blank Slate, and again today, Steve argued that
        social forces are over-rated as causes of gender differences.
     Intrinsic differences in aptitude are a larger factor, and intrinsic
      differences in motives are the biggest factor of all. Most of the
     examples that Steve gave concerned what he takes to be biologically
                        based differences in motives.

    My own view is different. I think the big forces causing this gap are
    social factors. There are no differences in overall intrinsic aptitude
     for science and mathematics between women and men. Notice that I am
     not saying the genders are indistinguishable, that men and women are
        alike in every way, or even that men and women have identical
      cognitive profiles. I'm saying that when you add up all the things
    that men are good at, and all the things that women are good at, there
    is no overall advantage for men that would put them at the top of the
                         fields of math and science.

       On the issue of motives, I think we're not in a position to know
     whether the different things that men and women often say they want
         stem only from social forces, or in part from intrinsic sex
               differences. I don't think we can know that now.

     I want to start with the issue that's clearly the biggest source of
      debate between Steve and me: the issue of differences in intrinsic
      aptitude. This is the only issue that my own work and professional
      knowledge bear on. Then I will turn to the social forces, as a lay
       person as it were, because I think they are exerting the biggest
      effects. Finally, I'll consider the question of intrinsic motives,
              which I hope we'll come back to in our discussion.
       [99][spelke_Page_04.jpg] Over the last months, we've heard three
     arguments that men have greater cognitive aptitude for science. The
    first argument is that from birth, boys are interested in objects and
       mechanics, and girls are interested in people and emotions. The
    predisposition to figure out the mechanics of the world sets boys on a
           path that makes them more likely to become scientists or
    mathematicians. The second argument assumes, as Galileo told us, that
      science is conducted in the language of mathematics. On the second
       claim, males are intrinsically better at mathematical reasoning,
       including spatial reasoning. The third argument is that men show
    greater variability than women, and as a result there are more men at
         the extreme upper end of the ability distribution from which
    scientists and mathematicians are drawn. Let me take these claims one
                                   by one.


    The first claim, as Steve said, is gaining new currency from the work
       of Simon Baron-Cohen. It's an old idea, presented with some new
      language. Baron-Cohen says that males are innately predisposed to
     learn about objects and mechanical relationships, and this sets them
     on a path to becoming what he calls "systematizers." Females, on the
     other hand, are innately predisposed to learn about people and their
      emotions, and this puts them on a path to becoming "empathizers."
    Since systematizing is at the heart of math and science, boys are more
    apt to develop the knowledge and skills that lead to math and science.

    To anyone as old as I am who has been following the literature on sex
       differences, this may seem like a surprising claim. The classic
     reference on the nature and development of sex differences is a book
    by Eleanor Maccoby and Carol Jacklin that came out in the 1970s. They
       reviewed evidence for all sorts of sex differences, across large
     numbers of studies, but they also concluded that certain ideas about
     differences between the genders were myths. At the top of their list
     of myths was the idea that males are primarily interested in objects
       and females are primarily interested in people. They reviewed an
     enormous literature, in which babies were presented with objects and
    people to see if they were more interested in one than the other. They
       concluded that there were no sex differences in these interests.

    Nevertheless, this conclusion was made in the early 70s. At that time,
    we didn't know much about babies' understanding of objects and people,
     or how their understanding grows. Since Baron-Cohen's claims concern
    differential predispositions to learn about different kinds of things,
      you could argue that the claims hadn't been tested in Maccoby and
                 Jacklin's time. What does research now show?

      Let me take you on a whirlwind tour of 30 years of research in one
    powerpoint slide. From birth, babies perceive objects. They know where
      one object ends and the next one begins. They can't see objects as
       well as we can, but as they grow their object perception becomes
                       richer and more differentiated.

      Babies also start with rudimentary abilities to represent that an
     object continues to exist when it's out of view, and they hold onto
       those representations longer, and over more complicated kinds of
       changes, as they grow. Babies make basic inferences about object
        motion: inferences like, the force with which an object is hit
      determines the speed with which it moves. These inferences undergo
            regular developmental changes over the infancy period.

    In each of these cases, there is systematic developmental change, and
     there's variability. Because of this variability, we can compare the
     abilities of male infants to females. Do we see sex differences? The
          research gives a clear answer to this question: We don't.

     Male and female infants are equally interested in objects. Male and
     female infants make the same inferences about object motion, at the
      same time in development. They learn the same things about object
                         mechanics at the same time.

     Across large numbers of studies, occasionally a study will favor one
    sex over the other. For example, girls learn that the force with which
    something is hit influences the distance it moves a month earlier than
     boys do. But these differences are small and scattered. For the most
       part, we see high convergence across the sexes. Common paths of
         learning continue through the preschool years, as kids start
    manipulating objects to see if they can get a rectangular block into a
    circular hole. If you look at the rates at which boys and girls figure
        these things out, you don't find any differences. We see equal
                             developmental paths.

    I think this research supports an important conclusion. In discussions
    of sex differences, we need to ask what's common across the two sexes.
       One thing that's common is infants don't divide up the labor of
    understanding the world, with males focusing on mechanics and females
     focusing on emotions. Male and female infants are both interested in
    objects and in people, and they learn about both. The conclusions that
      Maccoby and Jacklin drew in the early 1970s are well supported by
                          research since that time.
    [103][spelke_Page_08.jpg] Let me turn to the second claim. People may
        have equal abilities to develop intuitive understanding of the
       physical world, but formal math and science don't build on these
          intuitions. Scientists use mathematics to come up with new
       characterizations of the world and new principles to explain its
    functioning. Maybe males have an edge in scientific reasoning because
                   of their greater talent for mathematics.


    As Steve said, formal mathematics is not something we have evolved to
      do; it's a recent accomplishment. Animals don't do formal math or
    science, and neither did humans back in the Pleistocene. If there is a
      biological basis for our mathematical reasoning abilities, it must
    depend on systems that evolved for other purposes, but that we've been
     able to harness for the new purpose of representing and manipulating
                            numbers and geometry.

       Research from the intersecting fields of cognitive neuroscience,
       neuropsychology, cognitive psychology, and cognitive development
        provide evidence for five "core systems" at the foundations of
     mathematical reasoning. The first is a system for representing small
       exact numbers of objects -- the difference between one, two, and
     three. This system emerges in human infants at about five months of
    age, and it continues to be present in adults. The second is a system
      for discriminating large, approximate numerical magnitudes -- the
      difference between a set of about ten things and a set of about 20
      things. That system also emerges early in infancy, at four or five
        months, and continues to be present and functional in adults.

     The third system is probably the first uniquely human foundation for
      numerical abilities: the system of natural number concepts that we
    construct as children when we learn verbal counting. That construction
     takes place between about the ages of two and a half and four years.
     The last two systems are first seen in children when they navigate.
      One system represents the geometry of the surrounding layout. The
                  other system represents landmark objects.

    All five systems have been studied quite extensively in large numbers
     of male and female infants. We can ask, are there sex differences in
        the development of any of these systems at the foundations of
     mathematical thinking? Again, the answer is no. I will show you data
                             from just two cases.
      [106][spelke_Page_11.jpg] The first is the development of natural
     number concepts, constructed by children between the ages of two and
      four. At any particular time in this period, you'll find a lot of
     variability. For example, between the ages of three and three and a
      half years, some children have only figured out the meaning of the
    word "one" and can only distinguish the symbolic concept one from all
      other numbers. Other kids have figured out the meanings of all the
     words in the count list up to "ten" or more, and they can use all of
      them in a meaningful way. Most kids are somewhere in between: they
      have figured out the first two symbols, or the first three, and so
    forth. When you compare children's performance by sex, you see no hint
      of a superiority of males in constructing natural number concepts.

    [107][spelke_Page_12.jpg] The other example comes from studies that I
       think are the closest thing in preschool children to the mental
     rotation tests conducted with adults. In these studies, children are
    brought into a room of a given shape, something is hidden in a corner,
     and then their eyes are closed and they're spun around. They have to
    remember the shape of the room, open their eyes, and figure out how to
    rotate themselves back to the object where it was hidden. If you test
      a group of 4 year olds, you find they can do this task well above
      chance but not perfectly; there's a range of performance. When you
    break that performance down by gender, again there is not a hint of an
                        advantage for boys over girls.


    These findings and others support two important points. First, indeed
       there is a biological foundation to mathematical and scientific
      reasoning. We are endowed with core knowledge systems that emerge
        prior to any formal instruction and that serve as a basis for
    mathematical thinking. Second, these systems develop equally in males
      and females. Ten years ago, the evolutionary psychologist and sex
     difference researcher, David Geary, reviewed the literature that was
         available at that time. He concluded that there were no sex
    differences in "primary abilities" underlying mathematics. What we've
     learned in the last ten years continues to support that conclusion.

    Sex differences do emerge at older ages. Because they emerge later in
       childhood, it's hard to tease apart their biological and social
         sources. But before we attempt that task, let's ask what the
                               differences are.

       I think the following is a fair statement, both of the cognitive
       differences that Steve described and of others. When people are
      presented with a complex task that can be solved through multiple
       different strategies, males and females sometimes differ in the
                          strategy that they prefer.

    For example, if a task can only be solved by representing the geometry
     of the layout, we do not see a difference between men and women. But
    if the task can be accomplished either by representing geometry or by
         representing individual landmarks, girls tend to rely on the
    landmarks, and boys on the geometry. To take another example, when you
    compare the shapes of two objects of different orientations, there are
       two different strategies you can use. You can attempt a holistic
     rotation of one of the objects into registration with the other, or
    you can do point-by-point featural comparisons of the two objects. Men
       are more likely to do the first; women are more likely to do the

    Finally, the mathematical word problems on the SAT-M very often allow
      multiple solutions. Both item analyses and studies of high school
    students engaged in the act of solving such problems suggest that when
    students have the choice of solving a problem by plugging in a formula
     or by doing Ven diagram-like spatial reasoning, girls tend to do the
                    first and boys tend to do the second.

        Because of these differences, males and females sometimes show
     differing cognitive profiles on timed tests. When you have to solve
       problems fast, some strategies will be faster than others. Thus,
    females perform better at some verbal, mathematical and spatial tasks,
     and males perform better at other verbal, mathematical, and spatial
    tasks. This pattern of differing profiles is not well captured by the
     generalization, often bandied about in the popular press, that women
    are "verbal" and men are "spatial." There doesn't seem to be any more
         evidence for that than there was for the idea that women are
     people-oriented and men are object-oriented. Rather the differences
                               are more subtle.

    Does one of these two profiles foster better learning of math than the
    other? In particular, is the male profile better suited to high-level
                           mathematical reasoning?

     At this point, we face a question that's been much discussed in the
      literature on mathematics education and mathematical testing. The
    question is, by what yardstick can we decide whether men or women are
                               better at math?

      Some people suggest that we look at performance on the SAT-M, the
       quantitative portion of the Scholastic Assessment Test. But this
     suggestion raises a problem of circularity. The SAT test is composed
       of many different types of items. Some of those items are solved
      better by females. Some are solved better by males. The people who
    make the test have to decide, how many items of each type to include?
      Depending on how they answer that question, they can create a test
    that makes women look like better mathematicians, or a test that makes
       men look like better mathematicians. What's the right solution?

    Books are devoted to this question, with much debate, but there seems
     to be a consensus on one point: The only way to come up with a test
        that's fair is to develop an independent understanding of what
      mathematical aptitude is and how it's distributed between men and
     women. But in that case, we can't use performance on the SAT to give
      us that understanding. We've got to get that understanding in some
                  other way. So how are we going to get it?

    A second strategy is to look at job outcomes. Maybe the people who are
        better at mathematics are those who pursue more mathematically
    intensive careers. But this strategy raises two problems. First, which
         mathematically intensive jobs should we choose? If we choose
    engineering, we will conclude that men are better at math because more
      men become engineers. If we choose accounting, we will think that
    women are better at math because more women become accountants: 57% of
     current accountants are women. So which job are we going to pick, to
                   decide who has more mathematical talent?

      These two examples suggest a deeper problem with job outcomes as a
     measure of mathematical talent. Surely you've got to be good at math
     to land a mathematically intensive job, but talent in mathematics is
      only one of the factors influencing career choice. It can't be our
                   gold standard for mathematical ability.

     So what can be? I suggest the following experiment. We should take a
     large number of male students and a large number of female students
      who have equal educational backgrounds, and present them with the
    kinds of tasks that real mathematicians face. We should give them new
    mathematical material that they have not yet mastered, and allow them
     to learn it over an extended period of time: the kind of time scale
       that real mathematicians work on. We should ask, how well do the
     students master this material? The good news is, this experiment is
           done all the time. It's called high school and college.

     Here's the outcome. In high school, girls and boys now take equally
      many math classes, including the most advanced ones, and girls get
     better grades. In college, women earn almost half of the bachelor's
      degrees in mathematics, and men and women get equal grades. Here I
     respectfully disagree with one thing that Steve said: men and women
     get equal grades, even when you only compare people within a single
      institution and a single math class. Equating for classes, men and
                           women get equal grades.

     The outcome of this large-scale experiment gives us every reason to
    conclude that men and women have equal talent for mathematics. Here, I
     too would like to quote Diane Halpern. Halpern reviews much evidence
         for sex differences, but she concludes, "differences are not
    deficiencies." Men and women have equal aptitude for mathematics. Yes,
        there are sex differences, but they don't add up to an overall
                    advantage for one sex over the other.



      Let me turn to the third claim, that men show greater variability,
     either in general or in quantitative abilities in particular, and so
    there are more men at the upper end of the ability distribution. I can
     go quickly here, because Steve has already talked about the work of
        Camilla Benbow and Julian Stanley, focusing on mathematically
     precocious youth who are screened at the age of 13, put in intensive
    accelerated programs, and then followed up to see what they achieve in
                        mathematics and other fields.
    As Steve said, students were screened at age 13 by the SAT, and there
    were many more boys than girls who scored at the highest levels on the
       SAT-M. In the 1980s, the disparity was almost 13 to 1. It is now
      substantially lower, but there still are more boys among the very
    small subset of people from this large, talented sample who scored at
    the very upper end. Based on these data, Benbow and Stanley concluded
      that there are more boys than girls in the pool from which future
        mathematicians will be drawn. But notice the problem with this
       conclusion: It's based entirely on the SAT-M. This test, and the
        disparity it revealed, are in need of an explanation, a firmer
     yardstick for assessing and understanding gender differences in this
                             talented population.

      Fortunately, Benbow, Stanley and Lubinski have collected much more
      data on these mathematically talented boys and girls: not just the
     ones with top scores on one timed test, but rather the larger sample
     of girls and boys who were accelerated and followed over time. Let's
               look at some of the key things that they found.

    First, they looked at college performance by the talented sample. They
     found that the males and females took equally demanding math classes
     and majored in math in equal numbers. More girls majored in biology
     and more boys in physics and engineering, but equal numbers of girls
      and boys majored in math. And they got equal grades. The SAT-M not
     only under-predicts the performance of college women in general, it
    also under-predicted the college performance of women in the talented
    sample. These women and men have been shown to be equally talented by
    the most meaningful measure we have: their ability to assimilate new,
     challenging material in demanding mathematics classes at top-flight
    institutions. By that measure, the study does not find any difference
                   between highly talented girls and boys.

       So, what's causing the gender imbalance on faculties of math and
      science? Not differences in intrinsic aptitude. Let's turn to the
       social factors that I think are much more important. Because I'm
     venturing outside my own area of work, and because time is short, I
    won't review all of the social factors producing differential success
       of men and women. I will talk about just one effect: how gender
        stereotypes influence the ways in which males and females are
        Let me start with studies of parents' perceptions of their own
        children. Steve said that parents report that they treat their
      children equally. They treat their boys and girls alike, and they
      encourage them to equal extents, for they want both their sons and
    their daughters to succeed. This is no doubt true. But how are parents
                            perceiving their kids?

     Some studies have interviewed parents just after the birth of their
     child, at the point where the first question that 80% of parents ask
       -- is it a boy or a girl? -- has been answered. Parents of boys
     describe their babies as stronger, heartier, and bigger than parents
    of girls. The investigators also looked at the babies' medical records
     and asked whether there really were differences between the boys and
     girls in weight, strength, or coordination. The boys and girls were
      indistinguishable in these respects, but the parents' descriptions
                               were different.

      At 12 months of age, girls and boys show equal abilities to walk,
    crawl, or clamber. But before one study, Karen Adolph, an investigator
     of infants' locomotor development, asked parents to predict how well
     their child would do on a set of crawling tasks: Would the child be
    able to crawl down a sloping ramp? Parents of sons were more confident
         that their child would make it down the ramp than parents of
     daughters. When Adolph tested the infants on the ramp, there was no
     difference whatever between the sons and daughters, but there was a
                   difference in the parents' predictions.

     My third example, moving up in age, comes from the studies of Jackie
       Eccles. She asked parents of boys and girls in sixth grade, how
     talented do you think your child is in mathematics? Parents of sons
     were more likely to judge that their sons had talent than parents of
     daughters. A panoply of objective measures, including math grades in
    school, performance on standardized tests, teachers' evaluations, and
    children's expressed interest in math, revealed no differences between
        the girls and boys. Still, there was a difference in parents'
      perception of their child's intangible talent. Other studies have
                     shown a similar effect for science.

    There's clearly a mismatch between what parents perceive in their kids
       and what objective measures reveal. But is it possible that the
    parents are seeing something that the objective measures are missing?
     Maybe the boy getting B's in his math class really is a mathematical
        genius, and his mom or dad has sensed that. To eliminate that
    possibility, we need to present observers with the very same baby, or
       child, or Ph.D. candidate, and manipulate their belief about the
    person's gender. Then we can ask whether their belief influences their

      It's hard to do these studies, but there are examples, and I will
     describe a few of them. A bunch of studies take the following form:
    you show a group of parents, or college undergraduates, video-clips of
    babies that they don't know personally. For half of them you give the
     baby a male name, and for the other half you give the baby a female
        name. (Male and female babies don't look very different.) The
      observers watch the baby and then are asked a series of questions:
     What is the baby doing? What is the baby feeling? How would you rate
     the baby on a dimension like strong-to-weak, or more intelligent to
             less intelligent? There are two important findings.

    First, when babies do something unambiguous, reports are not affected
     by the baby's gender. If the baby clearly smiles, everybody says the
         baby is smiling or happy. Perception of children is not pure
     hallucination. Second, children often do things that are ambiguous,
     and parents face questions whose answers aren't easily readable off
    their child's overt behavior. In those cases, you see some interesting
       gender labeling effects. For example, in one study a child on a
    video-clip was playing with a jack-in-the-box. It suddenly popped up,
       and the child was startled and jumped backward. When people were
     asked, what's the child feeling, those who were given a female label
      said, "she's afraid." But the ones given a male label said, "he's
         angry." Same child, same reaction, different interpretation.

      In other studies, children with male names were more likely to be
    rated as strong, intelligent, and active; those with female names were
            more likely to be rated as little, soft, and so forth.
    [118][spelke_Page_25.jpg] I think these perceptions matter. You, as a
     parent, may be completely committed to treating your male and female
    children equally. But no sane parents would treat a fearful child the
     same way they treat an angry child. If knowledge of a child's gender
        affects adults' perception of that child, then male and female
       children are going to elicit different reactions from the world,
    different patterns of encouragement. These perceptions matter, even in
       parents who are committed to treating sons and daughters alike.


    I will give you one last version of a gender-labeling study. This one
    hits particularly close to home. The subjects in the study were people
    like Steve and me: professors of psychology, who were sent some vitas
     to evaluate as applicants for a tenure track position. Two different
       vitas were used in the study. One was a vita of a walk-on-water
    candidate, best candidate you've ever seen, you would die to have this
     person on your faculty. The other vita was a middling, average vita
    among successful candidates. For half the professors, the name on the
      vita was male, for the other half the name was female. People were
    asked a series of questions: What do you think about this candidate's
      research productivity? What do you think about his or her teaching
        experience? And finally, Would you hire this candidate at your

        For the walk-on-water candidate, there was no effect of gender
      labeling on these judgments. I think this finding supports Steve's
         view that we're dealing with little overt discrimination at
     universities. It's not as if professors see a female name on a vita
      and think, I don't want her. When the vita's great, everybody says
                              great, let's hire.

     What about the average successful vita, though: that is to say, the
     kind of vita that professors most often must evaluate? In that case,
     there were differences. The male was rated as having higher research
     productivity. These psychologists, Steve's and my colleagues, looked
     at the same number of publications and thought, "good productivity"
    when the name was male, and "less good productivity" when the name was
      female. Same thing for teaching experience. The very same list of
     courses was seen as good teaching experience when the name was male,
    and less good teaching experience when the name was female. In answer
     to the question would they hire the candidate, 70% said yes for the
    male, 45% for the female. If the decision were made by majority rule,
              the male would get hired and the female would not.

    A couple other interesting things came out of this study. The effects
      were every bit as strong among the female respondents as among the
    male respondents. Men are not the culprits here. There were effects at
    the tenure level as well. At the tenure level, professors evaluated a
      very strong candidate, and almost everyone said this looked like a
        good case for tenure. But people were invited to express their
     reservations, and they came up with some very reasonable doubts. For
     example, "This person looks very strong, but before I agree to give
    her tenure I would need to know, was this her own work or the work of
     her adviser?" Now that's a perfectly reasonable question to ask. But
     what ought to give us pause is that those kinds of reservations were
    expressed four times more often when the name was female than when the
                                name was male.

      So there's a pervasive difference in perceptions, and I think the
        difference matters. Scientists' perception of the quality of a
    candidate will influence the likelihood that the candidate will get a
      fellowship, a job, resources, or a promotion. A pattern of biased
      evaluation therefore will occur even in people who are absolutely
                         committed to gender equity.

        I have little doubt that all my colleagues here at Harvard are
        committed to the principle that a male candidate and a female
     candidate of equal qualifications should have equal chance at a job.
    But we also think that when we compare a more productive scholar to a
    less productive one, a more experienced teacher to a less experienced
    one, a more independent investigator to a less independent one, those
    factors matter as well. These studies say that knowledge of a person's
      gender will influence our assessment of those factors, and that's
    going to produce a pattern of discrimination, even in people with the
                               best intentions.

      From the moment of birth to the moment of tenure, throughout this
    great developmental progression, there are unintentional but pervasive
       and important differences in the ways that males and females are
                           perceived and evaluated.

     I have to emphasize that perceptions are not everything. When cases
     are unambiguous, you don't see these effects. What's more, cognitive
       development is robust: boys and girls show equal capacities and
        achievements in educational settings, including in science and
     mathematics, despite the very different ways in which boys and girls
    are perceived and evaluated. I think it's really great news that males
        and females develop along common paths and gain common sets of
     abilities. The equal performance of males and females, despite their
    unequal treatment, strongly suggests that mathematical and scientific
     reasoning has a biological foundation, and this foundation is shared
                            by males and females.

    Finally, you do not create someone who feels like a girl or boy simply
      by perceiving them as male or female. That's the lesson that comes
     from the studies of people of one sex who are raised as the opposite
     sex. Biological sex differences are real and important. Sex is not a
               cultural construction that's imposed on people.

        But the question on the table is not, Are there biological sex
    differences? The question is, Why are there fewer women mathematicians
      and scientists? The patterns of bias that I described provide four
     interconnected answers to that question. First, and most obviously,
      biased perceptions produce discrimination: When a group of equally
     qualified men and women are evaluated for jobs, more of the men will
    get those jobs if they are perceived to be more qualified. Second, if
     people are rational, more men than women will put themselves forward
    into the academic competition, because men will see that they've got a
     better chance for success. Academic jobs will be more attractive to
      men because they face better odds, will get more resources, and so

     Third, biased perceptions earlier in life may well deter some female
     students from even attempting a career in science or mathematics. If
       your parents feel that you don't have as much natural talent as
    someone else whose objective abilities are no better than yours, that
    may discourage you, as Eccles's work shows. Finally, there's likely to
        be a snowball effect. All of us have an easier time imagining
      ourselves in careers where there are other people like us. If the
    first three effects perpetuate a situation where there are few female
    scientists and mathematicians, young girls will be less likely to see
                     math and science as a possible life.

    So by my personal scorecard, these are the major factors. Let me end,
    though, by asking, could Steve also be partly right? Could biological
     differences in motives -- motivational patterns that evolved in the
     Pleistocene but that apply to us today -- propel more men than women
                 towards careers in mathematics and science?

    My feeling is that where we stand now, we cannot evaluate this claim.
    It may be true, but as long as the forces of discrimination and biased
     perceptions affect people so pervasively, we'll never know. I think
     the only way we can find out is to do one more experiment. We should
      allow all of the evidence that men and women have equal cognitive
       capacity, to permeate through society. We should allow people to
    evaluate children in relation to their actual capacities, rather than
    one's sense of what their capacities ought to be, given their gender.
     Then we can see, as those boys and girls grow up, whether different
    inner voices pull them in different directions. I don't know what the
     findings of that experiment will be. But I do hope that some future
                   generation of children gets to find out.

           Steven Pinker & Elizabeth Spelke: Concluding Discussion

    PINKER: Thanks, Liz, for a very stimulating and apposite presentation.
                            A number of comments.

    I don't dispute a lot of the points you made, but many have lost sight
      of the datum that we're here to explain in the first place. Basic
     abilities like knowing that an object is still there when you put a
    hankie over it, or knowing that one object can't pass through another,
    are not the kinds of things that distinguish someone who's capable of
     being a professor of physics or math from someone who isn't. And in
    many of the cases in which you correctly said that there is no gender
    difference in kids, there is no gender difference in adults either --
           such as the give-a-number task and other core abilities.

    Also, a big concern with all of the null effects that you mentioned is
      statistical power. Bob Rosenthal 20 years ago pointed out that the
       vast majority of studies that psychologists do are incapable of
        detecting the kinds of results they seek, which is why it's so
      important to have meta-analyses and large sample sizes. I question
       whether all of the null results that you mentioned can really be
      justified, and whether they are comparable to the studies done on
                            older kids and adults.

     One place where I really do disagree with you is in the value of the
     SAT-M, where the "circle" has amply been broken. This is what people
     at the College Board are obsessed with. What you are treating as the
    gold standard is performance in college courses. But the datum we are
    disputing is not how well boys and girls do in school, or how well men
       and women do in college, because there we agree there is no male
     advantage. The phenomenon we really are discussing is performance at
     the upper levels: getting tenure-track job, getting patents, and so
       on. And here the analyses have shown that the SAT is not biased
      against girls. That is, a given increment in SAT score predicts a
    given increment in the variable of interest to the same extent whether
                            you're male or female.

     I think there may be a slight difference in which finding each of us
       is alluding to in talking about differences in grades. I was not
      suggesting that girls' better grades come about because they take
       easier courses; they really do get better grades holding courses
    constant. Rather it's the slight underprediction of grades by the SAT
         that can be explained in part by class choice and in part by

    SPELKE: Well the most recent thing that I've read about this issue is
      the Gallagher and Kaufman book, Gender Differences in Mathematics,
     which just came out about a month ago. They report that equating for
    classes and institutions, and looking just at A students, there's a 21
    point SAT math differential; that is to say, for two students getting
     the same grade of A, the average for the girls on the SAT will have
    been 21 points lower. That differential is there at every grade level
                           and in all the courses.

    The SAT people have discussed it as a problem. One of the discussions
    reached the conclusion that the SAT is still useful, because although
        it under-predicts girls' performance in college, girls' grades
      over-predict their performance in college, and if you use the two
     together you are okay. In fact, they advised that people never take
     account of the SAT simply by itself, but consider it in relation to
      grades. When you spoke earlier about the use of GREs in admitting
     people to grad school, that's in fact what graduate programs do: We
                        consider both grades and GREs.

    Interestingly, though, in all of the public discussion of the relative
    advantages of men versus women for math and science, over the last two
    months, people have not used the SAT in conjunction with grades. When
      talking about relative ability, they've used the SAT by itself. I
       think that has led to a distorted conversation about this issue.

     PINKER: It nonetheless remains true that in the most recent study by
      Lubinski and Benbow, which showed a fantastic degree of predictive
       power of the SAT given in 7th grade, there was no difference in
         predictive power in boys and girls in any of these measures.

       But let me return to the datum that is at issue here, namely the
        differential representation of the sexes in physical sciences,
     mechanical engineering, and mathematics. The fact that men and women
     are equal overall in spatial abilities, and overall in mathematical
       abilities, is irrelevant to this. It may be that the particular
       subtalents in which women excel make them more likely to go into
    accounting. But the datum we are discussing is not a gender difference
     in accounting. The datum we are discussing is a gender difference in
      the physical sciences, engineering, and mathematics. And I suspect
      that when you look at a range of professions, the size of the sex
     discrepancy correlates with how much spatial manipulation (not just
      any kind of spatial cognition) and how much mathematical reasoning
        (not just any kind of mathematical ability) each of those jobs

         What about parents' expectations? In the 1970s the model for
     development was, "as the twig is bent, so grows the branch." -- that
     subtle differences in parents' perceptions early in life can have a
      lasting effect. You nudge the child in a particular direction and
     you'll see an effect on his trajectory years later. But there is now
    an enormous amount of research spearheaded by the behavioral genetics
     revolution suggesting that that is not true. There may be effects of
     parental expectations and parental treatment on young children while
    they're still in the home, but most follow-up studies show that short
        of outright abuse and neglect, these effects peter out by late
       adolescence. And studies of adoption and of twins and other sibs
     reared apart suggest that any effects of the kinds of parenting that
    are specific to a child simply reflect the preexisting genetic traits
      of the child, and the additional effect of parenting peters out to

     SPELKE: Can I respond to that? I think one thing is different about
    the gender case, compared to the early socialization effects for other
    kinds of categories, different styles of parenting, and so forth. The
        gender differences that we see reflected in parents' differing
       perceptions are mirrored by differing perceptions that males and
      females experience throughout their lives. It's not the case that
     idiosyncratic pairs of parents treat their kids one way, but then as
     soon as the children leave that environment, other people treat them
    differently. Rather, what we have in the case of gender is a pervasive
     pattern that just keeps getting perpetuated in different people. I'm
     rather a nativist about cognition, and I am tempted to look at that
    pattern and wonder, did Darwin give us some innately wrong idea about
      the genders? Professionals in professional contexts show the same
        patterns of evaluation that parents show in home contexts, and
      children face those patterns of evaluation, not just when they're
     young and at home, but continuing through high school, college, and
      finally with their colleagues on academic faculties. We're dealing
          here with a much more pervasive effect than the effects of
      socialization in the other studies that you've written and talked

     PINKER: Regarding bias: as I mentioned at the outset, I don't doubt
      that bias exists. But the idea that the bias started out from some
     arbitrary coin flip at the dawn of time and that gender differences
      have been perpetuated ever since by the existence of that bias is
            extremely unlikely. In so many cases, as Eagly and the
     Stereotype-Accuracy people point out, the biases are accurate. Also,
     there's an irony in these discussion of bias. When we test people in
       the cognitive psychology lab, and we don't call these base rates
    "gender," we applaud people when they apply them. If people apply the
       statistics of a group to an individual case, we call it rational
      Bayesian reasoning, and congratulate ourselves for getting them to
    overcome the cognitive illusion of base rate neglect. But when people
     do the same thing in the case of gender, we treat Bayesian reasoning
      as a cognitive flaw and base-rate neglect as rational! Now I agree
     that applying base rates for gender in evaluating individual men and
       women is a moral flaw; I don't think that base rates ought to be
            applied in judging individuals in most cases of public
      decision-making. But the fact that the statistics of a gender are
      applied does not mean that their origin was arbitrary; it could be
                      statistically sound in some cases.

     SPELKE: Let me reply to that, because I agree that the origin is not
     arbitrary, and that the bias is there for an objective reason, but I
    think you're drawing the wrong conclusion about it. I think the reason
    there's a bias to think that men have greater natural talent for math
       and science is that when we look around the world and ask, who's
      winning the Nobel Prizes and making the great advances in science,
                    what we see, again and again, is men.

    Although Linda Buck received this year's Nobel Prize in physiology or
     medicine, for the most part it's overwhelmingly men who are reaching
    the upper levels of math and science. It's natural to look at that and
     think, there must be some reason, some inner difference between men
     and women, which produces this enormous disparity. And I quite agree
    with you that good statistical reasoning should lead you to think, the
      next student who comes along, if male, is more likely to join that
                        group of Nobel Prize winners.

     What I would like to suggest is that we have good reasons to resist
      this kind of conclusion, and the reasons aren't only moral. Let me
    just use an analogy, and replay this debate over the biological bases
               of mathematics and science talent 150 years ago.

      Let's consider who the 19th century mathematicians and scientists
    were. They were overwhelmingly male, just as they are today, but also
    overwhelmingly European, not Asian. You won't see a Chinese face or an
     Indian face in 19th century science. It would have been tempting to
     apply this same pattern of statistical reasoning and say, there must
         be something about European genes that give rise to greater
    mathematical talent than Asian genes do. If we go back still further,
     and play this debate in the Renaissance, I think we would be tempted
     to conclude that Catholic genes make for better science than Jewish
    genes, because all those Renaissance scientists were Catholic. If you
        look at those cases, you see what's wrong with this argument.

     What's wrong with the argument is not that biology is irrelevant. If
       Galileo had been switched at birth with some baby from the Pisan
      ghetto, the baby raised by Galileo's parents would not likely have
     ended up teaching us that the language of physics is mathematics. I
     think that Galileo's genes had something to do with his achievement,
     but so did Galileo's cultural and social environment: his nurturing.
    Genius requires huge amounts of both. If, in that baby switch, Galileo
     had found himself growing up in the Pisan ghetto, I bet he wouldn't
     have ended up being the example in this discussion today either. So
    yes, there are reasons for this statistical bias. But I think we want
     to step back and ask, why is it that almost all Nobel Prize winners
    are men today? The answer to that question may be the same reason why
             all the great scientists in Florence were Christian.

      PINKER: I think you could take the same phenomenon and come to the
            opposite conclusion! Say there were really was such a
     self-reinforcing, self-perpetuating dynamic: a difference originates
     for reasons that might be arbitrary; people perceive the difference;
    they perpetuate it by their expectations. Just as bad, you say, is the
    fact that people don't go into fields in which they don't find enough
     people like themselves. If so, the dynamic you would expect is that
       the representation of different genders or ethnic groups should
     migrate to the extremes. That is, there is a positive feedback loop
     where if you're in the minority, it will discourage people like you
     from entering the field, which will mean that there'll be even fewer
     people in the field, and so on. On either side of this threshold you
        should get a drift of the percentages in opposite directions.
        Now, there is an alternative model. At many points in history,
     arbitrary barriers against the entry of genders and races and ethnic
    groups to various professions were removed. And as soon as the barrier
    was removed, far from the statistical underrepresentation perpetuating
     or exaggerating itself, as you predict, the floodgates open, and the
    formerly underrepresented people reaches some natural level. It's the
    Jackie Robinson effect in baseball. In the case of gender and science,
    remember what our datum is. It's not that women are under-represented
       in professions in general or in the sciences in general: in many
      professions women are perfectly well represented, such as being a
    veterinarian, in which the majority of recent graduates are women by a
    long shot. If you go back fifty years or a hundred years, there would
          have been virtually no veterinarians who were women. That
        underrepresentation did not perpetuate itself via the positive
                      feedback loop that you allude to.

        SPELKE: I'm glad you brought up the case of the basketball and
    baseball players. I think it's interesting to ask, what distinguishes
     these cases, where you remove the overt discrimination and within a
      very short period of time the differential disappears, from other
       cases, where you remove the overt discrimination and the covert
     discrimination continues? In the athletic cases where discrimination
     disappears quickly, there are clear, objective measures of success.
    Whatever people think about the capacities of a black player, if he is
    hitting the ball out of the park, he is going to get credit for a home
                    run. That is not the case in science.

    In science, the judgments are subjective, every step of the way. Who's
      really talented? Who deserves bigger lab space? Who should get the
     next fellowship? Who should get promoted to tenure? These decisions
      are not based on clear and objective criteria. These are the cases
     where you see discrimination persisting. You see it in academia. You
    see it in Claudia Goldin's studies of orchestra auditions, which also
    involve subtle judgments: Who's the more emotive, sensitive player? If
    you know that the players are male or female, you're going pick mostly
    men, but if the players are behind a screen, you'll start picking more

     PINKER: But that makes the wrong prediction: the harder the science,
    the greater the participation of women! We find exactly the opposite:
        it's the most subjective fields within academia -- the social
      sciences, the humanities, the helping professions -- that have the
       greatest representation of women. This follows exactly from the
     choices that women express in what gives them satisfaction in life.
    But it goes in the opposite direction to the prediction you made about
    the role of objective criteria in bringing about gender equity. Surely
      it's physics, and not, say, sociology, that has the more objective
                            criteria for success.

     SPELKE: Let me just say one thing, because I didn't say much in the
     talk at all, about this issue of motives, and biological differences
     in motives. That's been a less controversial issue, but I think it's
    an important one, and most of your examples were concerned with it. I
    think it's a really interesting possibility that the forces that were
       active in our evolutionary past have led men and women to evolve
     somewhat differing concerns. But to jump from that possibility into
    the present, and draw conclusions about what people's motives will be
        for pursuing one or another career, is way too big a stretch.

    As we both agree, the kinds of careers people pursue now, the kinds of
    choices they make, are radically different from anything that anybody
     faced back in the Pleistocene. It is anything but clear how motives
     that evolved then translate into a modern context. Let me just give
     one example of this. You've suggested, as a hypothesis, that because
       of sexual selection and also parental investment issues, men are
      selected to be more competitive, and women are selected to be more
     nurturant. Suppose that hypothesis is true. If we want to use it to
    make predictions about desires for careers in math and science, we're
      going to have to answer a question that I think is wide open right
              now. What makes for better motives in a scientist?

        What kind of motives are more likely to lead to good science:
      Competitive motives, like the motive J. D. Watson described in The
    Double Helix, to get the structure of DNA before Linus Pauling did? Or
    nurturant motives of the kind that Doug Melton has described recently
    to explain why he's going into stem cell research: to find a cure for
       juvenile diabetes, which his children suffer from? I think it's
      anything but clear how motives from our past translate into modern
         contexts. We would need to do the experiment, getting rid of
          discrimination and social pressures, in order to find out.


Guardian, Saturday April 30, 2005, pp 20-22, profile of John Brockman

     The son of a Boston wholesale flower seller, he adapted his father's
        business methods in his work as a pop publicist and management
        consultant. He went on to become a successful literary agent,
          specialising in top science writers and -- with an online
     'intellectual salon' -- building a reputation as a tireless promoter
               of influential ideas. Interview by Andrew Brown


     [cover.jpg] In 1968 John Brockman was promoting a film called Head ,
      starring the Monkees. His idea of publicity was simply to have the
        whole town covered in posters showing a head, with no caption.
       Naturally, the chosen head was his. Grotesquely solarised, with
    blue-grey lips and and scarlet spectacles, fashionable, suggestive of
     intellectual power, impossible to decipher, there he stood against a
            thousand walls, looking down on the city of New York.
    The posters have long since faded, but Brockman's position remains the
    same, gazing inscrutably on anything interesting in Manhattan. Now he
    is one of the most successful literary agents in the world, but to his
      friends and clients he is much more: an impresario and promoter of
      scientific ideas who is changing the way that all educated people
     think about the world. Richard Dawkins, his friend and client, says,
      "his Edge web site has been well described as an online salon, for
     scientists and for other intellectuals who care about science. John
           Brockman may have the most enviable address book in the
        English-speaking world, and he uses it to promote science and
            scientific literature in a way that nobody else does."

        Anyone today who thinks that scientists are the unacknowledged
     legislators of the world has been influenced by Brockman's taste. As
    well as Dawkins, he represents Daniel Dennett, Jared Diamond, and Sir
     Martin Rees, as well as three Nobel prize winners and almost all the
      other famous popular scientists. His old friend Stewart Brand, the
      publisher of the Whole Earth Catalog and later the promoter of the
      Clock of the Long Now, which is intended to run for 10,000 years,
      says: "It's so easy to think the guy's just a high-class pimp that
     it's quite easy to ignore the impact on the intellectual culture of
      the west that John has enabled by getting his artist and scientist
    friends out to the world. There is a whole cohort of intellectuals who
      are interacting with each other and would not [be able to] without
    Brockman himself says, "Confusion is good. Then try awkwardness. Then
         you fall back on contradiction. Those are my three friends."
    Fortunately, they are not his only friends. When asked for photographs
    of himself as a young man, he sends one where he is standing with Bob
     Dylan and Andy Warhol on the day Dylan visited Warhol's Factory. In
    the course of a couple of hours' conversation, he brings up encounters
     with (amongst others) John Cage; Robert Rauschenberg; Sam Sheppard;
     Larry Page and Sergei Brin, the founders of Google, with whom he had
        just had lunch along with his client Craig Venter, the genome
       researcher; "Rupert" (Murdoch); Stewart Brand; Elaine Pagels, an
    influential historian of religion; Hunter S Thompson; Richard Dawkins;
    Daniel Dennett; Nicholas Humphrey, the psychologist; Murray Gell-Mann,
     the Nobel-winning physicist; the actor Dennis Hopper; and Steve Case
                                   of AOL.

     He even mentions Huey P Newton, the Black Panther. "Sometime around
     1987 or '88, I get a call from Huey, who was a close friend of mine,
     who I was trying to avoid, because it had been revealed that he was
    actually gratuitously murdering people . . . you know, shooting them.
     He was flipping out. He wasn't talking about revolution or anything.
    Newton's message said: 'Me and my buddy Bob Trivers -- we're going to
    write a book on deceit and self-deception.'" Robert Trivers was one of
     the most important evolutionary biologists of the past 50 years, and
    came up with the hugely influential idea of "reciprocal altruism" as a
      graduate student at Harvard in the early 70s before his career was
     interrupted by psychological problems and he went off to live in the
    Jamaican jungle for some years. (He is now back at Harvard, in a chair
      funded by a friend of Brockman's.) Brockman continues: "Soon after
    that, he [Newton] died a very nasty death: just a crummy sidewalk dope
             deal. This was no way for a real revolutionary . . .

      "A couple of years ago, I made a rare visit to LA and was doing my
    favourite thing: watching the movie stars round the pool, and I got a
    message: Bob Trivers called. 'John. It's Bob Trivers. As I was saying.
          I've got the proposal ready. It's for a book on deceit and
    self-deception.'" Such a book will be ideal Brockman fodder. It takes
    science out to the edges of society yet deals with subjects of eternal
        importance. It captures a theory at the stage when it is most
     vigorously fighting for its life. It is written by the man who made
                 the discovery, which is an important point.
     Though Brockman has made some journalists a lot of money, his truly
    unique selling point is that he has made real scientists far more. In
    1999, for example, at the height of the pop science boom, he sold the
     world rights to a book by the theoretical physicist Brian Greene for
     $2m. Some of his books have proved initially trickier. Gell-Mann had
    to return an advance of $500,000 for a book, The Quark and the Jaguar,
    delivered late, that Bantam rejected. Brockman subsequently sold it to
                      WH Freeman for a reported $50,000.

     Many would agree that at least half his clients are truly remarkable
      thinkers, but there is room for disagreement about which half. For
    instance, he represents Sir John Maddox, the former editor of Nature,
     but also Rupert Sheldrake, whose heretical ideas about biology were
     denounced by Maddox in a Nature editorial that suggested Sheldrake's
    book A New Science of Life be burnt. Brockman has sold most of Richard
      Dawkins' books, but also the Bible Code by Michael Drosnin, which
     claimed that everything significant in the world up to the death of
      Princess Diana could have been predicted by reading every seventh
      letter in the Hebrew Bible, and the novel The Diary of a Manhattan
    Call Girl by Tracy Quan, which was the first account of a prostitute's
                    life to be serialised on the Internet.

     "He likes proposals to be about two pages long, no more, and then he
    likes to get an auction going," one of his authors says. "You'll get a
     call from him, and he's walking down Fifth Avenue on his cellphone,
     saying that he's got Simon & Schuster to bid 100,000 and now he will
     see what happens. A quarter of an hour later, Bantam has bid 125,000
     and then he says he'll go back to S&S and see if he can get 150,000.
      But he's got an attention span of about half an hour. If the book
                    isn't sold within a week, forget it."
     Tom Standage, the technology editor of the Economist, had his first
     book sold by Brockman on the basis of an outline one paragraph long.
    He sent it off in a speculative spirit and the next thing he heard was
     the rustle of a contract crawling towards him from the fax machine.
     Standage says: "He feels he's failed if a book earns out its advance
     and pays royalties because that means he hasn't got as much from the
                      publishers as he could have done."

     This is how the young Brockman learned from his father, a broker in
    the wholesale flower market in Boston, to hustle sales. "He dominated
    the carnation industry. He would go to the Boston flower market, which
     was owned by the growers, who formed a cooperative. All these Swedes
     and Norwegians would be growing gladiolas and carnations and they'd
       bring them in at three in the morning and leave them like a long
     aisle. There'd be thousands of flowers, and you had to sell them, or
    they died. He said to me 'you gotta move them, they're going to die'.
     And one day, 40 years later, I'm on the phone, and I had a chilling
    feeling as I felt my father's voice coming through me, like, 'they're
      going to die'. So, why am I always so fixated on closing the deal,
     getting the next book in? It comes from that experience. That was a
    pure market situation. So, that's the way I run my business. It's not
    literary. It's not publishing. It's business. I have got properties to
                        sell, on behalf of my clients.

       "My job is to do the best I can for them and I do it by making a
    market. The market decides. But knowing how to make a market involves
        . . . some capacities." The capacities are at the heart of his
      business, but it's hard to describe them. He has a keen sense for
       interesting ideas, but also for the ways in which they fit into
      society. For instance, he would never call himself an atheist, he
     says, in America: "I mean I don't believe: I'm sure there's no God.
    I'm sure there's no afterlife. But don't call me an atheist. It's like
     a losers' club. When I hear the word atheist, I think of some crummy
     motel where they're having a function and these people have nowhere
       else to go. That's what it means in America. In the UK it's very

       The Brockmans were the children of immigrants -- John's father's
      family had come from Austria -- and grew up in a largely poor and
    Catholic neighbourhood of Boston and he remains extremely sensitive to
      anti-Semitism. "There were no books in our house. My father could
    barely read. He was a brilliant man but he was on the streets working
    at eight years old. My mother read a little bit, but, you know, it was
                            a little encyclopedia.

    "My parents were poor. My father started a business the day I was born
        which became a successful business. But we grew up in a tough
    neighbourhood called Dorchester, which was an Irish-Catholic bastion,
      where this radical right-wing priest went up and down the streets
    telling people to kill Jews. So that's how my brother and I grew up."
    He has one brother, a retired physicist, who is three years older. "We
      quickly found out, going to school, that . . . we were personally
    responsible for the death of Jesus Christ. We had a lot of fighting to
    do, and most of it on the losing end, because there were always 30 of
      them to two of us. My brother got the worse of it. My mother was a
     tough cookie. She would kick him out of the house if he didn't fight
    hard enough. Luckily in those days you didn't get killed; you just got
                      a bloody nose. But it was tough."

       "Confusion is good. Then try awkwardness. Then you fall back on
                 contradiction. Those are my three friends."

     This mixture of pugnacity and sensitivity about ethnicity can still
    surface. When he was upset by a profile in the Sunday Times magazine,
     which he thought played to an anti-Semitic stereotype, he complained
      straight to Rupert Murdoch (using Murdoch's banker, another of his
                        contacts, as an intermediary).
    Brockman was a poor student in high school and was turned down for 17
       colleges before studying business, finishing up with an MBA from
    Columbia University in New York. He worked selling tax shelters for a
    while, but in the evenings he was hanging out with all the artists he
       could find. He stacked chairs in the theatre with the young Sam
    Sheppard; he went to dinner parties with John Cage; he started to put
    on film festivals and then multi-media extravagances at about the same
    time as Ken Kesey's Merry Pranksters in San Francisco and Andy Warhol
    in New York. This early attraction to the art world seems to have set
     his style. The art that he was involved with qualified as art simply
                  because everyone involved decided it was.

     In this flux, it seemed the only certainty was scientific truth, but
       he was early attracted to the idea of science, of computing as a
    metaphor for everything. Stewart Brand first met him in the early 60s:
    "I was in the army as an officer and spending the weekends in New York
     -- he was in the thick of the multimedia scene that was the cutting
      edge of performance pop art. He was an impresario, who could help
    organise events and people and media and be essential to the process,
     but unlike a lot of people he was actually alert to what the art was
    about, just as later, as an agent, he was alert to what the books were
    about. So far as I was concerned he was another artist in the group of
                         artists I was running with."

    Life at a glance

    John Brockman

    Born: February 16 1941 Boston, Massachusetts.

    Educated: Babson Institute of Business Administration; Columbia
    University, New York.

    Employment: 1965-69 Multimedia artist; '74-present, literary agent;
    founder Brockman, Inc; chairman Content.com.

    Married: Katinka Matson (one son, Max, 1981).

    Some books: 1969 By the Late John Brockman; '88 Doing Science: The
    Reality Club; '95 The Third Culture; '96 Digerati: Encounters with the
    Cyber Elite; '03 The Next Fifty Years: Science in the First Half of
    the Twenty-First Century; '04 Science at the Edge.

      In 1967 Brockman discovered how to sell flower power while it was
    still fresh. A business school friend who had gone to work for a paper
    company asked Brockman to help motivate the sales force for their line
      of sanitary towels. This was at a time when the New York Times was
      solemnly explaining that "Total environment" discothèques, such as
      Cheetah and The Electric Circus in New York, were turning on their
     patrons with high-decibel rock'n'roll combined with pulsing lights,
     flashing slide images, and electronic "colour mists". Brockman asked
         -- and got -- a fee of $15,000 despite having no consulting
    experience. He put on a multimedia show for the salesmen: they lay on
    the floor of a shiny vinyl wigwam while four sound systems played them
        Beatles songs, bird calls, company advertising slogans with an
     executive shouting about market statistics and competitive products,
    and a film showed a young woman wearing a dress made of the company's
         paper which she ripped down to her navel. In the 60s it was
    cutting-edge art, an "intermedia kinetic experience", and the salesmen
     exposed to it reportedly sold an additional 17% of feminine hygiene
       products in the next quarter. Brockman took the show around nine
    cities for the company, energising its sales force nationwide, and was
      established as a consultant who could sell his services to anyone.

        But it was not enough. His book By the Late John Brockman was
      unfavourably reviewed, but he was not discouraged and continued to
      write and edit books -- 18 at last count. One, Einstein, Gertrude
     Stein, Wittgenstein and Frankenstein , had to be hurriedly withdrawn
    after portions were found to have been plagiarised from an article by
     James Gleick, the author of Chaos , one of the first big pop science
    hits and not a Brockman client. Brockman blamed one of his assistants.
    Brockman's later books have mostly been collections of interviews with
    friends and clients, salted and sometimes vinegared as well with their
    opinions of each other. He has a made a Christmas tradition of asking
     questions of 100 or so people and circulating their responses. "What
    do you believe to be true, but cannot prove?" was the most recent one,
     in 2004, and is a fine example of Brockman's method as an editor or
     curator of thought. The question was supplied by Nicholas Humphrey,
       but it was Brockman who spotted its potential, and then knew 120
      interesting people who were prepared to answer it. Humphrey's own
    answer is characteristically thought-provoking: "I believe that human
    consciousness is a conjuring trick, designed to fool us into thinking
       we are in the presence of an inexplicable mystery . . . so as to
    increase the value we each place on our own and others' lives." Philip
      Anderson, the Nobel Prize-winning physicist, believes that string
    theory is a waste of time. Randolph Nesse, an evolutionary biologist,
      believes, but cannot prove, that believing things without proof is
          evolutionary advantageous; Ian McEwan that no part of his
                      consciousness will survive death.

    Brockman has constantly reinvented himself. He has been at the leading
     edge of intellectual fashion for the past 30 years. In the late 90s,
      just before the dot.com bubble popped, he told an interviewer from
     Wired magazine that he wanted to be "post-interesting". Looking back
    on all the ideas he has enthused about you glimpse a mind that rushes
      around like a border collie -- tirelessly and gracefully pursuing
     anything that moves, but absolutely uninterested in things that stay
     still, and liable, if shut up in a car, to get bored and eat all the
     upholstery. Like a lot of successful salesmen, part of his secret is
    that he is interested in people for their own sake as well as for what
          they can do for him, and can study them with extraordinary
    concentration, solemnly placing out, beside the journalist's machine,
    two tape recorders of his own at the beginning of an interview. To be
    under his attentive, almost affectionate gaze, is to know how a sheep
                         feels in front of a collie.

     Twice in the course of a couple of hours' chat he says "you ought to
     write a book about that". He became a book agent by accident. He was
     talking about God to the scientist John Lilly, a friend of Brand's,
    whose research into dolphins and LSD was one of the first tendrils of
    a scientific study of consciousness, and he realised Lilly had a book
    there. He sold the proposal and found a new business where his talents
                         and his interests coincided.
     He has been in the vanguard of the trend towards larger advances at
       the expense of royalties, and a model of rewards in which a few
     superstars make gigantic sums and almost everyone else makes next to
    nothing. His first enormous commercial success came in the early 80s,
     as personal computers started to appear. He understood that software
    manuals would need publishing just as normal books do. In the end, the
     idea of software publishers didn't work out, but not before Brockman
    had made a fortune from the idea. He started an annual dinner for the
    other players in the business, called the millionaires' dinner. Later,
    when this seemed unimpressive, he renamed it the billionaires' dinner;
    then the scientists' dinner -- whatever worked to bring lively people
                                  round him.

    He works with and is married to Katinka Matson, the daughter of a New
    York literary agent who was AD Peters's partner in 50s. "She actually
    makes the wheels turn in the office," says Tom Standage. The Brockmans
           have one son, Max, who works in the family business as a
     third-generation agent, and who was blessed in his crib by a drunken
    dance performed round it by Hunter S Thompson, Dennis Hopper and Gerd
           Stern, a multi-media artist from the avant-garde scene.

      After the first boom in personal computers and their software blew
    out, Brockman was perfectly placed for the next boom, in writing about
      the people who made it. The house magazine of that boom was Wired,
      which sold itself to Conde Nast as "The magazine which branded the
    digital age"; it is almost an obligation on the editor of Wired to be
    a Brockman client. He set out his manifesto in the early 90s for what
    he called the Third Culture: "Traditional American intellectuals are,
      in a sense, increasingly reactionary, and quite often proudly (and
      perversely) ignorant of many of the truly significant intellectual
     accomplishments of our time. Their culture, which dismisses science,
      is often non-empirical. By contrast, the Third Culture consists of
       those scientists and other thinkers in the empirical world who,
    through their work and expository writing, are taking the place of the
     traditional intellectual in rendering visible the deeper meanings of
                 our lives, redefining who and what we are."
      Everything was speeding up, too. Brockman had always been quick to
    close a deal. Now he demanded pinball-fast reactions from the editors
      he sold to. One trick was to watch the front page of the New York
     Times and get a quick book proposal out of every science story that
     appeared there. This mean that if you were a Brockman client on the
         staff of the New York Times a front page splash was not just
       professionally gratifying, but also a potential route to a large
    cheque. There was a danger that this constituted a temptation to hype.
    When one New York Times journalist, Gina Kolata, followed a "cure for
    cancer" splash with a book contract the next day, there was an outcry
                    and the book was eventually cancelled.

     For Brockman, America now is the intellectual seedbed for Europe and
      Asia. He wrote: "The emergence of the Third Culture introduces new
      modes of intellectual discourse and reaffirms the pre-eminence of
         America in the realm of important ideas. Throughout history,
    intellectual life has been marked by the fact that only a small number
     of people have done the serious thinking for everybody else. What we
     are witnessing is a passing of the torch from one group of thinkers,
         the traditional literary intellectuals, to a new group, the
      intellectuals of the emerging Third Culture. Intellectuals are not
    just people who know things but people who shape the thoughts of their
         generation. An intellectual is a synthesiser, a publicist, a
         communicator." Brockman, it hardly needs saying, is the true
                            intellectual's agent.
       Of course, this was angrily resented by those outside the magic
      circle, especially if they were themselves intellectuals in every
    respect save being represented by him. But any anger or ridicule stays
     off the record. Who knows when they will need to deal with him? Who
    knows when he could bless them with a million dollars, and whisk them
                            into the magic circle?

      Yet it is a tribute to Brockman's personality that people who have
    known him a long time like him a great deal. Stewart Brand says: "The
    salon-keeper has an interesting balancing act between highlighting the
         people they're attracted to and also having a strong enough
    personality so that they are taken seriously as a peer. People do not
    feel threatened by him or competitive with him. They either admire him
      or profess to be amused by him. But you look behind that, and you
              realise that they don't look down on him at all."

       The magic circle has gone by different names and using different
      degrees of formality. In the 90s it was a manifested in a physical
     gathering, run with Heinz Pagels, called the Reality Club. The elite
    would come together and talk about the work that interested them. They
       didn't have to be his clients, and many of them weren't. But all
       invested their time in ideas he was promoting. Pagels died in an
       accident and Brockman says he didn't have the heart to go on by
      himself. Instead, he set up his Edge website, where he puts up new
    interviews every month, which can be read as transcripts or watched as
                          videos, with commentaries.

     It all reinforces his idea that reality is essentially social. Even
    the name, the Reality Club, goes right back to his earliest big idea:
     that reality is what the smart people, who should be friends of John
     Brockman, decide to make of the world: "It's an argument that I have
     with all my scientist friends, and I lose it every time. They don't
     buy it at all. It's very primitivistic, I'm told, or even solipsism,
                            but it works for me."

    Linda S. Gottfredson responds to Simon Baron-Cohen

    Sociologist, School of Education, University of Delaware
    Simon Baron-Cohen's work joins the search for causal mechanisms
    linking genes, brain, and behavior. The patterned variation by sex at
    all three levels of analysis provides clues to what those mechanisms
    might be (e.g., testosterone). Baron-Cohen employs those patterns to
    better understand, in particular, the etiology of autism and its much
    higher prevalence among males.
    Variation is the raw material for much scientific analysis and for
    evolution itself, but public discussion of human variation seems
    mostly off-limits today. We are called upon to celebrate diversity but
    not notice difference; to observe a new etiquette that forbids
    utterance of supposedly tactless knowledge. Good feeling compels
    public ignorance. But bewildered or bemused, outraged or apprehensive,
    most scientists soldier on.
    Baron-Cohen continues to investigate the nature of sex differences.
    His research on babies only 24 hours old, while needing replication,
    fits the larger pattern of sex differences in interests, personality,
    and abilities across the lifespan. For instance, at all ages and
    worldwide, females tend to be more interested in people and males in
    inanimate objects. As noted in earlier commentaries, humans are not
    the only primates showing this pattern. It would have been an
    exception to the rule had Baron-Cohen's team not found boys gazing
    more at the mechanical object and girls more at the human face. Like
    the habituation research now used to assay differences in cognitive
    ability among infants, his results provide prima facie evidence that
    socialization cannot be the sole cause of variation in social
    behavior. The interesting question is not whether meaningful innate
    sex differences exist, but how anyone could construe the preponderance
    of evidence otherwise.
    Baron-Cohen argues that the distinction between "systematizers"
    (disproportionately male) and "empathizers" (disproportionately
    female) is especially important in the etiology of autism. He
    theorizes that genetic risk of autism rises when both parents are
    systematizers. While onto something important, his work might advance
    faster and persuade better if, rather than proposing a new
    distinction, it exploited existing evidence on the dimensionality and
    relatedness of human psychological traits (all of them heritable),
    particularly interests ("Holland's hexagon" of six modal types),
    personality (the "big five"--or three or seven), and abilities (the
    "3-stratum hierarchical model").

    Researchers in vocational interest measurement, personality
    assessment, personnel testing, and differential psychology have spent
    a century parsing, cataloguing, and correlating these differences
    among individuals. They find a regular pattern of sex differences
    regardless of age, time, or place. It is not clear where Baron-Cohen's
    systematizer-empathizer distinction fits in this much-explored
    territory, but it would seem to map best onto dimensions in the
    non-cognitive realm: sympathetic vs. cold ("agreeableness" personality
    dimension), "realistic" vs. "social" vocational interests, or valuing
    "ideas" vs. "feeling."
    Prevalence of autism has increased so much recently that some label it
    epidemic. Baron-Cohen must explain how this increase is consistent
    with evidence that autism has strong genetic roots. The two facts are
    not inconsistent, but many people assume they are. They fallaciously
    reason that if prevalence jumps within only decades (e.g., more
    violent crime, more women getting BAs in math), then the behavior in
    question must not be genetically influenced because the gene pool
    could not have changed during that time. But it need not have.
    First, non-random mating can change the distribution of phenotypes in
    the next generation of the same gene pool. Baron-Cohen's theory would
    predict that more assortative mating for "systematizing" will lead to
    more autism in the offspring generation. It would operate like
    inbreeding, which increases the odds of offspring inheriting the same
    deleterious recessive allele from both parents. This explanation
    doesn't work well, however, for rates of socially important behaviors
    that fluctuate within a generation (e.g., criminal behavior, which has
    a heritable component), and perhaps not even for autism.
    Second, environmental change matters, but not equally for all
    genotypes. When environments become more deleterious, the more
    susceptible genotypes are the first casualties. Environmental toxins
    may be one such factor in autism. Conversely, as environments become
    more favorable, some genotypes are better able to exploit the new
    opportunities. So, as barriers to women in education and work have
    fallen, the most talented and ambitious women have been the best
    placed to advance. In neither case has the gene pool changed--only the
    environments favoring some genotypes over others.
    Third, different genotypes seek and evoke different experiences and
    environments. Outgoing, agreeable, feelings-oriented personalities
    prefer (and are preferred for) dealing with people; non-social,
    pragmatic, things-oriented personalities find a better fit working
    with mechanical objects and processes. When free to choose, the two
    types will gravitate toward different careers. They will also create
    different personal environments for themselves and their children. So,
    just as low-IQ parents don't create the most propitious environments
    for their genetically at-risk children, perhaps two systematizers
    provide non-optimal rearing for theirs too.

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                   [147]John Brockman, Editor and Publisher
                 [148]Russell Weinberger, Associate Publisher
                        [149]contact: editor at edge.org


  124. http://www.edge.org/documents/archive/gdn1.pdf
  125. http://www.edge.org/documents/archive/gdn2.pdf
  126. mailto:eamonn.mccabe at btinternet.com
  127. mailto:refuseinc at earthlink.net
  128. mailto:tobiaseverke at mac.com
  129. http://www.everke.com/
  130. http://books.guardian.co.uk/review/story/0,12084,1472567,00.html
  131. http://books.guardian.co.uk/review/story/0,12084,1472567,00.html
  132. http://www.edge.org/3rd_culture/bios/gottfredson.html
  133. http://www.edge.org/books/curious_index.html
  134. http://www.edge.org/books/curious_index.html
  138. http://www.edge.org/books/new_humanists.html
  139. http://www.edge.org/books/new_humanists.html
  142. http://www.edge.org/books/next50_index.html
  143. http://www.edge.org/books/next50_index.html
  147. http://www.edge.org/3rd_culture/bios/brockman.html
  148. http://www.edge.org/3rd_culture/bios/weinberger.html
  149. mailto:editor at edge.org

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