Sunday, September 07, 2003

Study shows environment trumps genetics for poor kids

George Kelly of All About George, a supporter of Silver Rights from its very first week, alerted me to some good news this week. New research reveals poor black children are impacted more by their environments than by genetic endowments, something I've believed all along.

Back-to-school pop quiz: Why do poor children, and especially black poor children, score lower on average than their middle-class and white counterparts on IQ tests and other measures of cognitive performance?

It is an old and politically sensitive question, and one that has long fueled claims of racism. As highlighted in the controversial 1994 book The Bell Curve, studies have repeatedly found that people's genes -- and not their environment -- explain most of the differences in IQ among individuals. That has led a few scholars to advance the hotly disputed notion that minorities' lower scores are evidence of genetic inferiority.

Now a groundbreaking study of the interaction among genes, environment and IQ finds that the influence of genes on intelligence is dependent on class. Genes do explain the vast majority of IQ differences among children in wealthier families, the new work shows. But environmental factors -- not genetic deficits -- explain IQ differences among poor minorities.

Eric Turkheimer, a psychologist at the University of Virginia, decided to look beyond the conventional wisdom and lack thereof. He wondered if the bleakness of many poor children's environments might need to be addressed before jumping to conclusions about their innate ability -- a rather obvious inquiry if one is not blinded by bias. He concludes "the influence of genes on IQ was significantly lower in conditions of poverty, where environmental deficits overwhelm genetic potential." The study will be published in the November edition of the scholarly journal Psychological Science.

A colleague of Turkheimer's explains why this research matters.

"This paper shows how relevant social class is" to children's ability to reach their genetic potential, said Sandra Scarr, a professor emerita of psychology now living in Hawaii, who did seminal work in behavioral genetics at the University of Virginia.

Specifically, the heritability of IQ at the low end of the wealth spectrum was just 0.10 on a scale of zero to one, while it was 0.72 for families of high socioeconomic status. Conversely, the importance of environmental influences on IQ was four times stronger in the poorest families than in the higher status families.

"This says that above a certain level, where you have a wide array of opportunities, it doesn't get much better" by adding environmental enhancements, Scarr said. "But below a certain level, additional opportunities can have big impacts."

Those of us who grew up among the disadvantaged already know that neither poor children nor low-income adults are stupid in general. Instead, their skills tend to fit their surroundings and what society suggests they are capable of. A boy who could just as easily have become an engineer with adequate educational opportunities and encouragement sets his eye on the unlikely goal of basketball stardom instead. A girl of modest vocal ability develops an unrealistic notion of becoming the next pop diva, though her real strength is empathy for others and she would make an excellent nurse or social worker. Many of the people in the demographic simply become inured to academic failure early and stop trying, as Dr. Benjamin Carson, one of the most respected neurosurgeons in the world, says he did for a time.

Fortunately, most people in Bloggersville are not so insecure that they run screaming from the thought of black people being just as intelligent as any other group.

Tapped gets it:

Stated simply, the study found that environmental factors loom much larger in the development of children when they have a low socioeconomic status, and much smaller when they have a high one. What this suggests is that for people on the lower end of the totem pole, a bad environment -- that is, high rates of crime, concentrated poverty, crumbling schools -- can overwhelm those otherwise predisposed to high achievement, while people born into a more positive environment, with a wide array of opportunities, are more likely to get a chance to express their natural gifts and abilities. This makes sense intuitively, but it also has some precedent in the natural world.

Rick Heller of Smart Genes, also a strong supporter of this blog, suggests additional reading on the topic of heritability, H. Allen Orr's review of Matt Ridley's Nature via Nurture: Genes, Experience, and What Makes Us Human.

Part of the significance of Turkheimer's study is that it will lead to others which will hopefully bolster the realization that tangible intervention in the lives of poor children can improve their lives for the longrun. Contrary to the delusional thinking of white supremacists, a child who reads well at seven will not have forgotten how at 27 because of the melanin content of his skin. When I was a poor child in Lumbee land, my third grade teacher, Ms. Ross, took it upon herself to supply me with books for the rest of my elementary school career. Though I learned to read at four and had jaw-droppingly high IQ scores, our home held little that was stimulating for bright children, as all five of us were. I believe that kind of intervention, on a large scale, and not out of a schoolteacher's wallet, can make a difference. If real reform comes, the entire society will reap its rewards.

Note: A longer version of his entry originally appeared at Silver Rights, a weblog focusing on civil rights and related issues.

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