Nature, Nurture, and Destiny: The Bell Curve Revisited: What Science Teaches Us about Heredity and Environment
Kirp, David L., The American Prospect
IN MAKING THE CASE FOR BETTER early education programs, advocates rely heavily on bench science. Neuroscientists are summoned to demonstrate the palpable impact of severe deprivation in the first years of life--recall the horrific accounts of the Romanian orphans--and to show, with vivid MRI images, how early experience builds the scaffolding for everything that follows, as the brain incorporates early experience into its biological structure.
Mention genetics, however, and the advocates immediately change the subject. Those with an appreciation of history know that the American Eugenics Movement proposed sterilizing the "unfit" and that Hitler's Germany used the research for unspeakable purposes. When psychologist Richard Lerner wrote about the misuse of genetics, he pointedly titled his book Final Solution. And you don't have to be a history buff to recall that, in the mid-1990s, The Bell Curve became the bible of social conservatives with its conclusion that genetically-based IQ deficiencies of African Americans explain their disproportionate rates of poverty and incarceration, and that early education was a waste of money. Most recently, eminent scientist James Watson opined that he was "inherently gloomy about the prospect of Africa" because "all our social policies are based on the fact that their intelligence is the same as ours--whereas all the testing says not really." Science must address questions of genetics and intelligence, he added, though the answers may be "cruel."
But as widespread denunciation of Watson's remarks suggests, liberals no longer have to fear genetics. Quite the contrary--the "heredity versus environment" model, the intellectual underpinning of The Bell Curve, is itself wrong. A new generation of studies shows that genes and environment don't occupy separate spheres, that much of what is labeled "hereditary" becomes meaningful only in the context of experience. When it comes to explaining life outcomes it's not nature versus nurture but nature through nurture. What's more, in the topsy-turvy social world in which many poor kids grow up, it's almost all about nurture.
Such findings give added scientific heft to the preschool research that shows the effects of high-quality early education on an array of life outcomes. Those iconic studies demonstrate that early educational experiences can make a major difference. Genetics, no less than neuroscience, helps to explain why.
Over the years, studies of adopted children have found that their IQ scores are considerably closer to their biological parents' scores than to their adoptive parents' scores. That led geneticists to a logical conclusion: Intelligence is mainly inherited. But the newest research, looking at a range of other variables--especially poverty--has upended the conventional wisdom by showing the profound importance of the environment on later aptitude.
In one instance, experts tracked French youngsters from hardscrabble backgrounds--abusive homes, impersonal institutions, multiple foster care placements and the like--whose IQ scores averaged just 77, borderline retardation. Nine years after they were adopted, all of their scores had improved. Those adopted into affluent families jumped the most--their progress was directly associated with their new socioeconomic status. The only, and crucial, difference among these children was the lives they'd led after being adopted.
Other research, notably by University of Virginia psychologist Eric Turkheimer, has focused on outcomes for twins, the gold standard in the field. Earlier research had shown that IQ differences were considerably smaller for identical than for fraternal twins, a finding consistent with the hereditarian view. But Turkheimer was the first researcher to focus on IQ differences between twins from poor and non-poor families. The key finding: Variations in IQ scores for twins from well-off families are mainly genetic, while heredity explains almost none of the IQ differences for twins in the poorest families. …