The Bell Curve Controversy

With the publication of The Bell Curve (1994) by Richard J. Herrnstein and Charles Murray, The Decline of Intelligence in America (1994) by Seymour W. Itzkoff, and Race, Evolution, and Behavior (1994) by J. Philippe Rushton, debate over the relationship between genetics and intelligence has been re-ignited. Although the precise subject matter of the books differs, the authors share several controversial convictions: intelligence—the ability to reason, think abstractly, and organize information—can be quantitatively measured and expressed as I.Q.; intelligence is largely immutable and at least partially heritable, therefore linked to race; I.Q. scores correlate, although weakly, with job performance and rates of birth, crime, participation in the political process, and welfare dependency; and society must allow for topics regarding intelligence and race to be freely debated. The authors of The Bell Curve, which has so far received the most attention, postulate that present trends in reproduction in the United States favor the eventuality of a nation split between a ruling caste of high-I.Q. "meritocrats" and a large, powerless underclass that lacks the intelligence to prosper in a society dominated by sophisticated machines. Democracy will disintegrate in such a society, Herrnstein and Murray warn, while racial hatred and alienation will grow as America becomes a "custodial" state. The authors draw much of their evidence from the National Longitudinal Survey of Youth, a study of more than twelve thousand high school students who were tested in 1979 and have had their progress tracked ever since; and the Armed Forces Qualification Test, a general intelligence test which the military uses to predict success in military training schools. The authors argue that core intelligence has been the single most important determinate of success in the National Longitudinal Survey and that the Armed Forces Qualification Test has proven to be an extremely reliable predictor. The term "bell curve," from which the book's title derives, refers to the shape of a normal distribution graph, which bulges in the middle and narrows at the edges. The majority of people, being of average intellect, form the bulge in the middle, while the low and high achievers make up the bell's edges. As Malcolm W. Browne has noted, Herrnstein and Murray "frequently refer to bell curves to make a point: that predictions about any individual based exclusively on his or her I.Q. are virtually useless. It is only when weak correlations between intelligence and job success are applied to large groups of people that they have predictive value. Within statistically large groups of people, the authors say, the pervasive influence of I.Q. on human society becomes evident."

Critical reaction to The Bell Curve has generally been negative, with many commentators denouncing the book as a racist product of conservative ideology. However, as Christopher Winship has argued, "much of The Bell Curve is not about race at all, and parts of it have been misrepresented." Winship and other critics note that a sizeable portion of the book deals solely with the relationship between behavior and I.Q. among whites and that Herrnstein and Murray believe that only sixty percent, not one hundred percent, of intelligence is genetically determined. One of the most contentious claims in The Bell Curve is that intelligence is, for the most part, not improvable. Numerous critics have attacked Herrnstein and Murray's bleak prognosis, arguing that educational programs for disadvantaged children like Head Start do make a difference and that society can work to alter the social environment and therefore positively influence the population's general intelligence. One of the major problems with such statistical studies as Herrnstein and Murray's, scholars argue, is the difficulty of isolating determinate factors in a system as complex as human society and the resulting danger of overlooking other variables. Herrnstein and Murray have been criticized as well for failing to discuss and substantiate the theoretical basis behind their claims regarding intelligence and for ignoring significant studies in the fields of genetics, psychometrics, sociology, and psychology which would compromise their conclusions. Remarking on the durability of their arguments, Stephen Jay Gould has commented: "Intelligence, in their formulation, must be depictable as a single number, capable of ranking people in linear order, genetically based, and effectively immutable. If any of these premises are false, their entire argument collapses…. The central argument of The Bell Curve fails because most of the premises are false." Still, several opponents of The Bell Curve's conclusions, such as Gregg Easterbrook, are grateful for Herrnstein and Murray's work, since it brings "the arguments about race, inheritance, and IQ out into the open … because the more you know about this line of thought, the less persuasive it becomes."