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Science/Tech See other Science/Tech Articles Title: Unsettled Scores This much is uncontested: for most of the 20th century, blacks worldwide have scored, on average, 15 points lower on most IQ tests than whites have. What scientists cannot agree on is why. Most attribute the gap to differences in education, health and other environmental influences. Hereditarians, on the other hand, view the black-white difference as largely genetic in origin. They note, among other indirect evidence, that the disparity persists across time and around the world — a permanence that is crucial to the debate over what explains group differences. “If black-white differences converged—if there wasn’t this whopping big difference everywhere—there’d be no debate left,” says J. Philippe Rushton, a psychologist at the University of Western Ontario and an outspoken hereditarian. So it was big news when William T. Dickens and James R. Flynn published a paper in Psychological Science in October 2006 concluding that African-Americans have greatly reduced the racial IQ gap. Drawing on their analysis of four different IQ tests taken between 1972 and 2002, including the Stanford-Binet and the Armed Forces Qualification Test, the researchers say that blacks in the U.S. have gained four to seven IQ points on non-Hispanic whites, thus closing a quarter to half the gap. To Dickens and Flynn, the implications are obvious. “The gap isn’t fixed in the stars,” says Flynn, a professor of political studies at the University of Otago in Dunedin, New Zealand, who is best known for his observations of across-the-board IQ gains over time — evidence that environmental factors strongly drive scores. Dickens, a senior fellow in economic studies at the Brookings Institution, adds that future progress toward equal opportunity should continue to reduce the disparity. But the evidence does not justify such optimism, says Rushton, who calls himself a race realist. When Rushton peer-reviewed the study, he argued for its rejection on the grounds that the data were cherry-picked, because it ignored at least four IQ tests whose results showed either no black gains or even a slight decline. In the end, he published a forceful commentary on the study, coauthored with the eminent (and controversial) psychologist Arthur Jensen of the University of California, Berkeley. Dickens and Flynn rebutted, stating that they had excluded samples that were not representative of the U.S. population. For example, in one sample one group had more education than the race it represented, and it was not clear which race that was. Dickens believes most IQ test publishers simply do not try to restandardize their tests using nationally representative samples, making it hard for researchers to draw definitive inferences. Linda Gottfredson, an education professor at the University of Delaware, points to a more serious question in the findings. If black IQ is rising, and if IQ is the best predictor of academic achievement, one would expect a similar rise in standardized achievement tests. Yet, she notes, most studies show no such gain. For instance, Charles Murray, a scholar at the conservative think tank American Enterprise Institute and author of the controversial 1994 best-seller The Bell Curve, published a report on black achievement in the December 2006 issue of the journal Intelligence; he concludes that although blacks started closing the school achievement gap during the 20th century, progress stopped for people born since the mid-1970s. Dickens explains these discrepancies in part through different ways of looking at the same data. “No one doubts that there is an achievement gap,” he says. “The question is whether it has narrowed, and the answer is yes,” although the gains have not been equal on all measures. Gottfredson also points to a troublesome trend in the 30-year data that Dickens and Flynn used — namely, at each successive age, the black-white gap steadily increases. “All these data are interpreted as a slam dunk for environmental explanations, when they’re at least as consistent with genetic ones,” she says, adding that the effects of family environment tend to wash out with age. In the Dickens and Flynn model, on the other hand, an impoverished family environment actually creates greater disadvantages with age. For example, Dickens explains, “it’s much less of a problem for a four- or five-yearold to have a high school dropout for a mother than for a 16-year-old,” because poorly educated parents cannot help with advanced schoolwork. If black progress has stalled, demographic changes may be to blame. Whereas high-IQ women of all races have lower birth rates, the birth rates of high-IQ black women in particular have “gone through the floor,” says Murray—leaving a shortage of both the best genes and the best family environments for the next generation. He adds that even if it were possible to answer the genetic question once and for all, as he believes today’s DNA testing can help to do, most scientists would shy away from such research for political reasons. Because genes interact with the environment, some researchers think the question of genetic differences by race is pointless. “What does that mean?” asks Eric Turkheimer, a University of Virginia psychologist who has explored poverty’s effect on realizing an individual’s genetic potential. What Rushton and Jensen must be arguing, he says, “is that a gap will remain under any environmental influence. And how can you possibly know that? All you can show is it’s been very frustrating to reduce.”
Poster Comment: Most excellent for a mainstream publication.
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#1. To: Tauzero (#0)
This was debunked right after it came out. If Africans average IQ of 70 were not genetic, they'd have created a civilization worthy of the name. They've only had 20,000 or so years.
#2. To: YertleTurtle (#1)
True, but still. The dam is cracking.
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