[Paleopsych] Slate: Amanda Schaffer: Cave Thinkers: How evolutionary psychology gets evolution wrong.

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Amanda Schaffer: Cave Thinkers: How evolutionary psychology gets evolution 
    Posted Tuesday, Aug. 16, 2005, at 4:16 AM PT

    This spring, New York Times columnist John Tierney asserted that men
    must be [24]innately more competitive than women since they monopolize
    the trophies in--hold onto your vowels--world Scrabble competitions.
    To bolster his case, Tierney turned to [25]evolutionary psychology. In
    the distant past, he argued, a no-holds-barred desire to win would
    have been an adaptive advantage for many men, allowing them to get
    more girls, have more kids, and pass on their competitive genes to
    today's word-memorizing, vowel-hoarding Scrabble champs.

    Tierney's peculiar, pseudo-scientific claim--[26]not the first from
    him--reflects the extent to which evolutionary psychology has
    metastasized throughout public discourse. EP-ers' basic claim is that
    human behavior stems from psychological mechanisms that are the
    products of natural selection during the Stone Age. Researchers often
    focus on how evolution produced mental differences between men and
    women. One of EP's academic stars, David Buss, argues in his salacious
    new book [27]The Murderer Next Door that men are wired to kill
    unfaithful wives because this response would have benefited their
    distant forefathers. Larry Summers took [28]some cover from EP this
    winter after his remarks about women's lesser capacity to become top
    scientists. And adaptive explanations of old sexist hobbyhorses--men
    like young women with perky breasts and can't stop themselves from
    philandering because these urges aided ancestral reproduction--are
    commonly marshaled in defense of ever-more-ridiculous [29]playboys.

    Evolutionary psychologists have long taken heat from critics for
    overplaying innate characteristics--nature at the expense of
    nurture--and for reinforcing gender stereotypes. But they've dismissed
    many detractors, fairly or no, as softheaded feminists and
    sociologists who refuse to acknowledge the true power of natural
    selection. Increasingly, however, attacks on EP come from academics
    well-versed in the hard-nosed details of evolutionary biology. A case
    in point is the new book [30]Adapting Minds by philosopher David
    Buller, which was supported by a research grant from the National
    Science Foundation and published by MIT Press and has been getting
    glowing reviews [31]like this one (paid link) from biologists. Buller
    persuasively argues that while evolutionary forces likely did play a
    role in shaping our minds, the assumptions and methods that have
    dominated EP are weak. Much of the work of pioneers like [32]Buss,
    [33]Steven Pinker, [34]John Tooby, [35]Leda Cosmides, [36]Martin Daly,
    and [37]Margo Wilson turns out to be vulnerable on evolutionary

    EP claims that our minds contain hundreds or thousands of "mental
    organs" or "modules," which come with innate information on how to
    solve particular problems--how to interpret nuanced facial
    expressions, how to tell when someone's lying or cheating. These
    problem-solving modules evolved between 1.8 million and 10,000 years
    ago, during the Pleistocene epoch. And there the selection story ends.
    There has not been enough time in the intervening millenia, EP-ers
    say, for natural selection to have further resculpted our psyches.
    "Our modern skulls house a Stone Age mind," as Cosmides' and Tooby's
    [40]primer on evolutionary psychology puts it. The way forward for
    research is to generate hypotheses about the urges that would have
    been helpful to Stone Age baby-making and then try to test whether
    these tendencies are widespread today.

    What's wrong with this approach? To begin with, we know very little
    about the specific adaptive problems faced by our distant forebears.
    As Buller points out, "We don't even know the number of species in the
    genus Homo"--our direct ancestors--"let alone details about the
    lifestyles led by those species." This makes it hard to generate good
    hypotheses. Some EP-ers have suggested looking to modern-day
    hunter-gatherers as proxies, studying them for clues about our
    ancestors. But this doesn't get them far. For instance, in some
    contemporary African groups, men gather the bulk of the food; in other
    groups, women do. Which groups are representative of our ancestors?
    Surely there's a whole lot of guesswork involved when evolutionary
    psychologists hypothesize about the human brain's supposedly formative

    In addition, we are probably not psychological fossils. New research
    suggests that evolutionary change can occur [41]much faster than was
    previously believed. Natural selection is thought to effect rapid
    change especially when a species' environment is in flux--precisely
    the situation in the last 10,000 years as humans learned to farm,
    domesticate animals, and live in larger communal groups. Crucially,
    Buller notes, in order for significant change to have occurred in the
    human mind in the last 10 millennia, evolution need not have built
    complex brain structures from scratch but simply modified existing

    Finally, the central, underlying assumption of EP--that humans have
    hundreds or thousands of mental problem-solving organs produced by
    natural selection--is questionable. Many cognitive scientists believe
    that such modules exist for processing sensory information and for
    acquiring language. It does not follow, however, that there are a
    plethora of other ones specifically designed for tasks like detecting
    cheaters. In fact, considering how much dramatic change our forebears
    faced, it makes more sense that their problem-solving faculties would
    have evolved to be flexible in response to their immediate
    surroundings. (A well-argued [42]book from philosopher Kim Sterelny
    fleshes out this claim.) Indeed, our mental flexibility, or
    [43]cortical plasticity, may be evolution's greatest gift.

    So, if evolutionary psychology has so many cracks in its foundations,
    why is it so stubbornly influential? It helps that EP-ers like Buss
    and Pinker are lively, media-friendly writers who present topics like
    sex, love, and fear in simple terms. More to the point for scientists,
    EP's conclusions can be quite difficult to falsify. Even if its
    methods of generating hypotheses are suspect, there is always the
    possibility that on any given topic, an EP-er will turn out to be
    partly right. That forces critics to delve into the details of
    particular empirical claims. Buller does this in the latter part of
    his book and successfully dismantles several major EP findings.

    For instance, EP-ers have asserted that stepparents are more likely to
    abuse their stepchildren than their own sons and daughters because in
    the Stone Age, the parents who selectively devoted love and resources
    to their own progeny would have had a leg up in passing on their own
    genes. The proof is data that purport to show a higher rate of
    modern-day abuse by stepparents than by parents. When Buller dissects
    the data, however, this conclusion begins to fall apart. To begin
    with, most of the relevant studies on abuse do not say whether the
    abuser was a parent or stepparent. The EP assumption that the abuser
    is always the stepparent creates an artificial and entirely absurd
    confirmation of the field's hypothesis. In addition, research has
    shown that when a stepfather is present, a child's bruises are more
    likely attributed to abuse rather than to accidents, whereas when a
    biological father is present, the opposite tendency exists. Buller has
    to wade in deep to unravel this, but the effort pays off.

    Ultimately, the biggest problem with EP may be that it underestimates
    the power of evolutionary forces--both to tinker continually with the
    human brain, and to have created ingenious and flexible
    problem-solving structures in the first place. There's a nice irony
    here, since for years EP-ers have ridiculed opponents for not
    appreciating evolutionary theory's core tenets. Buller goes so far as
    to note an eerie resemblance between EP and [44]intelligent design,
    which also treats human nature as fixed and complete. The more
    persuasive claim is that there is no single human nature, and that
    we're works in progress.

    Related in Slate

    Jacob Weisberg [45]argued that scientists should acknowledge that
    evolution and religion aren't compatible. Bob Wright [46]explained why
    Steven Jay Gould can't be trusted. Judith Shulevitz [47]laid out
    evolutionary psychology's take on why men rape.

    Amanda Schaffer is a frequent contributor to Slate.
    posted Aug. 16, 2005


   25. http://www.anth.ucsb.edu/projects/human/evpsychfaq.html
   27. http://us.penguingroup.com/nf/Book/BookDisplay/0,,0_1594200432,00.html
   28. http://pinker.wjh.harvard.edu/articles/media/2005_02_14_newrepublic.html
   29. http://news.independent.co.uk/uk/health_medical/article294039.ece
   31. http://www.sciencemag.org/cgi/content/full/309/5735/706
   32. http://homepage.psy.utexas.edu/homepage/Group/BussLAB/AboutDavid.htm
   33. http://pinker.wjh.harvard.edu/
   34. http://www.anth.ucsb.edu/faculty/tooby/
   35. http://www.psych.ucsb.edu/people/faculty/cosmides/index.php
   36. http://www.science.mcmaster.ca/Psychology/md.html
   37. http://www.science.mcmaster.ca/Psychology/margo.html
   38. http://slate.msn.com/id/2124503/#ContinueArticle
   40. http://www.psych.ucsb.edu/research/cep/primer.html
   41. http://www.newscientist.com/article.ns?id=mg18725071.100
   43. http://slate.msn.com/id/2124503/sidebar/2124504/
   44. http://slate.msn.com/id/2118388/
   45. http://slate.msn.com/id/2124297/
   46. http://slate.msn.com/id/2016/
   47. http://slate.msn.com/id/1004368/

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