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Tuesday, June 23, 2009

Evo psych succumbs to EVIDENCE

Loved this excellent article by Newsweek's terrific science writer, Sharon Begley, explaining how the underlying principles of evolutionary psychology (stating that modern male domination is based on evolution) have been mortally wounded by research evidence. Here are some excerpts:

These have not been easy days for evolutionary psychology. For years the loudest critics have been social scientists, feminists and liberals offended by the argument that humans are preprogrammed to rape, to kill unfaithful girlfriends and the like. (This was a reprise of the bitter sociobiology debates of the 1970s and 1980s. When Harvard biologist Edward O. Wilson proposed that there exists a biologically based human nature, and that it included such traits as militarism and male domination of women, left-wing activists—including eminent biologists in his own department—assailed it as an attempt "to provide a genetic justification of the status quo and of existing privileges for certain groups according to class, race, or sex" analogous to the scientific justification for Nazi eugenics.)

Evo psych took its first big hit in 2005, when NIU's Buller exposed flaw after fatal flaw in key studies underlying its claims, as he laid out in his book Adapting Minds. Anthropological studies such as Hill's on the Ache, shooting down the programmed-to-rape idea, have been accumulating. And brain scientists have pointed out that there is no evidence our gray matter is organized the way evo psych claims, with hundreds of specialized, preprogrammed modules. Neuroscientist Roger Bingham of the University of California, San Diego, who describes himself as a once devout "member of the Church of Evolutionary Psychology" (in 1996 he created and hosted a multimillion-dollar PBS series praising the field), has come out foursquare against it, accusing some of its adherents of an "evangelical" fervor. Says evolutionary biologist Massimo Pigliucci of Stony Brook University, "Evolutionary stories of human behavior make for a good narrative, but not good science."

Like other critics, he has no doubt that evolution shaped the human brain. How could it be otherwise, when evolution has shaped every other human organ? But evo psych's claims that human behavior is constrained by mental modules that calcified in the Stone Age make sense "only if the environmental challenges remain static enough to sculpt an instinct over evolutionary time," Pigliucci points out. If the environment, including the social environment, is instead dynamic rather than static—which all evidence suggests—then the only kind of mind that makes humans evolutionarily fit is one that is flexible and responsive, able to figure out a way to make trade-offs, survive, thrive and reproduce in whatever social and physical environment it finds itself in.

. . . "Depend on"? The very phrase is anathema to the dogma of a universal human nature. But it is the essence of an emerging, competing field. Called behavioral ecology, it starts from the premise that social and environmental forces select for various behaviors that optimize people's fitness in a given environment. Different environment, different behaviors—and different human "natures."

. . . Evolutionary psychology is not going quietly. It has had the field to itself, especially in the media, for almost two decades. In large part that was because early critics, led by the late evolutionary biologist Stephen Jay Gould, attacked it with arguments that went over the heads of everyone but about 19 experts in evolutionary theory. It isn't about to give up that hegemony . . . evo psych remains hugely popular in the media and on college campuses, for obvious reasons. It addresses "these very sexy topics," says Hill. "It's all about sex and violence," and has what he calls "an obsession with Pleistocene just-so stories." And few people—few scientists—know about the empirical data and theoretical arguments that undercut it. "Most scientists are too busy to read studies outside their own narrow field," he says.

. . . And for a final nail in the coffin, geneticists have discovered that human genes evolve much more quickly than anyone imagined when evolutionary psychology was invented, when everyone assumed that "modern" humans had DNA almost identical to that of people 50,000 years ago. Some genes seem to be only 10,000 years old, and some may be even younger.

That has caught the attention of even the most ardent proponents of evo psych, because when the environment is changing rapidly—as when agriculture was invented or city-states arose—is also when natural selection produces the most dramatic changes in a gene pool. Yet most of the field's leaders, admits UNM's Miller, "have not kept up with the last decade's astounding progress in human evolutionary genetics." The discovery of genes as young as agriculture and city-states, rather than as old as cavemen, means "we have to rethink to foundational assumptions" of evo psych, says Miller, starting with the claim that there are human universals and that they are the result of a Stone Age brain. Evolution indeed sculpted the human brain. But it worked in malleable plastic, not stone, bequeathing us flexible minds that can take stock of the world and adapt to it.

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