Posted on December 5, 2007

Dissecting the IQ Debate: A Response to William Saletan’s Series on Race and IQ.

Stephen Metcalf, Slate, December 3, 2007


[William] Saletan’s analogy implies that the conflict over race, intelligence, and genetics is a conflict between science and superstition. It’s not; it’s a conflict between science and science. Worse, even when Saletan shades his rhetoric carefully, the reader is left with the impression that science—hard, empirical disinterested science—is trending to a hereditarian explanation for the IQ gap, and that bad or weak science—really a kind of wishful, mushy, quasi-superstitious scientism—is on the side of an environmental or cultural explanation. If you explore the subject in any depth, or even just click through to some of Saletan’s own links, you find the opposite is closer to the truth.


We’ll get to their “science” in a moment, but first: Who are these two men? J. Philippe Rushton is the head of America’s most dedicated subsidizer and promoter of eugenic research, the Pioneer Fund, which I have written about here. Arthur Jensen has spent the last 40 years arguing against “compensatory education,” or the idea that programs like Head Start have any efficacy in alleviating black underachievement. (Think about it: Jensen began claiming that black mental inferiority was intractable a mere five years after the Civil Rights Act, four years after the Voting Rights Act, and four years after Head Start was created.) Since the late ’60s—i.e., since the heyday of civil rights and the inception of such “compensatory education” programs as Head Start—blacks have made huge gains vis-à-vis whites on a wide range of standardized tests. For obvious reasons, Rushton and Jensen refuse to acknowledge these gains.


But let’s give Rushton and Jensen the benefit of the doubt, and peek for a minute under the hood. On inspection, what does their own meta-analysis look like? Rushton and Jensen admire the famous “Minnesota twin study,” in which black, white, and mixed-race adoptees were placed into white families. It has become a kind of gold standard for the researchers who believe the IQ gap is hereditary, and Rushton and Jensen devote a full seven paragraphs to it. Here is what you would never know about the Minnesota study from reading Jensen and Rushton, or, for that matter, Saletan. It held neither race nor expected IQ constant; the black children were adopted at a later age than the other children, which the study’s own authors note is associated with depressed IQ; the black children’s mothers had lower educational levels than those of the white children; the “quality of placement” for the white children was higher than for the other children; and as the study’s own authors have noted, the black and mixed-race children experienced severe adjustment problems as they grew up.*

Much of Saletan’s précis of the rest of the research surveyed in “Thirty Years of Research Into Race Differences on Cognitive Abilities” is highly questionable. His takeaway regarding the “admixture” studies is precisely the opposite of what an American Psychological Association task force concluded the studies show—that more “European” blood in a black American does not make him smarter. Saletan points up the problems with a favorite study of the environmentalists, into the IQ outcomes of children fathered by foreign soldiers and raised by (white) German mothers. This study showed that kids with African fathers scored the same as those with white fathers. But, Saletan says, it suffers from a fatal flaw: Blacks in the military had been screened for IQ. Saletan concludes, “Even environmentalists (scholars who advocate nongenetic explanations) concede that this filter radically distorted the numbers.” But this is flatly untrue. The two most prominent environmentalists, Richard Nisbett and James Flynn, have dismissed this very objection. Both have pointed out that white soldiers were also screened, and so had higher IQs than the general white population. James Flynn has argued extensively that the black-white gap in the military was the same as in the population at large.

Saletan uses a sheer volume of statistics to create an aura of gathering unanimity, but many of his statistics have been taken at face value. To take one example: Saletan casually countenances the assertion that the mean IQ of sub-Saharan Africa is 70. The number arrives to us via a man named Richard Lynn. Lynn is the author of the 1996 volume “Dysgenics: Genetic Deterioration in Modern Populations.” In “historical societies,” Lynn wrote, “illegitimate children, born predominantly to parents with low intelligence and weak character, suffered high mortality.” Until the scourge of modern medicine, such culling assured the expulsion of weaklings from the gene pool, while the “operation of positive natural selection” ensured the “reproductive fitness of the leaders and of the upper and middle classes.” The instrument Lynn used to apprehend these depressed IQ scores is a supposedly culturally unbiased exam called Raven’s Progressive Matrices. “To use an instrument developed in the West on semi and possibly illiterate people is a fool’s errand,” says Nisbett, a Distinguished University Professor at the University of Michigan who studies cognition and social psychology. “Then they use the results to say that half the people in Africa are mentally retarded. It’s laughable.”

Saletan places faith in an in-depth task force report from the American Psychological Association, titled “Intelligence: Knowns and Unknowns,” dating from 1996. The task force, Saletan admits, “doesn’t conclude that genes explain racial gaps in IQ. But the tests on which racial gaps are biggest happen to be the tests on which genes, as measured by comparative sibling performance, exert the biggest influence.” Saletan’s rapid summary makes it sound as though the task force drew the necessary dots, then, experiencing a failure of nerve, refused to connect them. Nothing could be further from the truth. The APA made its conclusions absolutely clear: There is some inconclusive evidence that culture factors account for the IQ gap between blacks and whites, and there is “even less empirical support for a genetic explanation.”

Furthermore, the APA task force lays out—finally!—the real heart of the conflict. To understand what is really being fought over when we fight over the IQ gap between blacks and whites, its authors explain, you must think through an analogy. Imagine two wheat fields. Now imagine two genetically identical sets of seeds. (The analogy was first made famous by the Harvard evolutionary biologist and geneticist Richard Lewontin.) Now imagine each field is planted with these two identical seed stocks. Field No. 1 is given the best possible inputs: sunshine intensity, rain, soil nitrates, etc. Field No. 2 is given much less of all of the above. Within each field, inputs are kept uniform. Inevitably, the first field grows a healthier supply of grain than the second. But here is the rub: Within each field, the variation in outcomes is entirely hereditary. Between the two fields, the variation in outcomes in entirely environmental.


Are the environmental and cultural situations of American Blacks and Whites also substantially and consistently different—different enough to make this a good analogy? If so, the within-group heritability of IQ scores is irrelevant to the issue. Or are those situations similar enough to suggest that the analogy is inappropriate, and that one can plausibly generalize from within-group heritabilities? Thus the issue ultimately comes down to personal judgment: How different are the relevant life experiences of Whites and Blacks in the United States today?

To the APA’s superb list, I would add some related queries. Does it feel as though researchers like Jensen and Rushton, the so-called “race realists,” have spent their careers examining a range of competing hypotheses for the black-white IQ gap, and carefully scrutinizing the quality of the research at their disposal? Or have they been attempting, at all costs, to prove a single hypothesis—that blacks are congenitally dumber than whites? Shouldn’t researchers on any highly charged subject be required to show a minimum of clean hands? Why is it that every researcher I can find who supports the heredity-only thesis takes money from the Pioneer Fund? Would you ever take money from the Pioneer Fund? Under any circumstances?


Correction, Dec. 5, 2007: The Minnesota twin study referred to throughout this paragraph was originally identified as having been subsidized by the Pioneer Fund. In fact, this study, led by Sandra Scarr, has no connection to the Pioneer Fund. It was another, contemporaneous Minnesota twin study, led by Thomas J. Bouchard, that received funding from the organization.

[Editor’s Note: ARNews carried excerpts from Saletan’s series that may be found here, here, and here.]

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