Paroxysms of Denial
Arthur Jensen
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Nowadays the factual basis of The Bell Curve is scarcely debated by the experts, who regard it as mainstream knowledge.
The most well-established facts: Individual differences in general cognitive ability are reliably measured by IQ tests. IQ is strongly related, probably more than any other single measurable trait, to many important educational, occupational, economic and social variables. (Not mentioned in the book is that IQ is also correlated with a number of variables of the brain, including its size, electrical potentials, and rate of glucose metabolism during cognitive activity.) Individual differences in adult IQ are largely genetic, with heritability of about 70 percent. So far, attempts to raise IQ by educational or psychological means have failed to show appreciable lasting effects on cognitive ability and scholastic achievement. The IQ distribution in two population groups socially recognized as "black" and "white" is represented by two largely overlapping bell curves with their means separated by about 15 points, a difference not due to test bias. IQ has the same meaning and practical predictive validity for both groups. Tests do not create differences; they merely reflect them.
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Although social problems involving race are conspicuously in the news these days, too few journalists are willing or able to discuss rationally certain possible causes. The authors' crime, apparently, is that they do exactly this, arguing with impressive evidence that the implications of IQ variance in American society can't be excluded from a realistic diagnosis of its social problems.
The media's spectacular denial probably arises from the juxtaposition of the book's demonstrations; first, that what is termed "social pathology" -- delinquency, crime, drug abuse, illegitimacy, child neglect, permanent welfare dependency -- is disproportionately concentrated (for whites and blacks alike) in the segment of the population with IQs below 75; and second, that at least one-fourth of the black population (compared to one-twentieth of the white population) falls below that critical IQ point in the bell curve. Because the smaller percentage of white persons with IQs below 75 are fairly well scattered throughout the population, many are guided, helped, and protected by their abler families, friends, and neighbors, whose IQs average closer to 100. Relatively few are liable to be concentrated in the poor neighborhoods and housing projects that harbor the "critical mass" of very low IQs which generates more than its fair share of social pathology. The "critical mass" effect exists mostly in the inner city, which has been largely abandoned by whites. Of course thinking citizens are troubled. Thinking about possible constructive remedies strains one's wisdom.
But can any good for anyone result from sweeping the problem under the rug? Shouldn't it be exposed to earnest, fair-minded public discussion? Our only fear, I think, should be that such discussion might not happen. Consideration of the book's actual content is being displaced by the rhetoric of denial: name calling ("neo-nazi," "pseudo-scientific," "racism"), sidetracks ("but does IQ really measure intelligence?"), non-sequiturs ("specific genes for IQ have not been identified, so we can claim nothing about its heritability"), red herrings ("Hitler misused genetics"), falsehoods ("all the tests are biased"), hyperbole ("throwing gasoline on a fire"), and insults ("creepy," "indecent," "ugly").