The Bell Curve: Intelligence and Class Structure in American Life Read Free Page B

“general intelligence.” The evidence for a general factor in intelligence was pervasive but circumstantial, based on statistical analysis rather than direct observation. Its reality therefore was, and remains, arguable.
    Spearman then made another major contribution to the study of intelligence by defining what this mysterious
g
represented. He hypothesized that
g
is a general capacity for inferring and applying relationships drawn from experience. Being able to grasp, for example, the relationship between a pair of words like
harvest
and
yield,
or to recite a list of digits in reverse order, or to see what a geometrical pattern would look like upside down, are examples of tasks (and of test items) that draw on
g
as Spearman conceived of it. This definition of intelligence differed subtly from the more prevalent idea that intelligence is the ability to learn and to generalize what is learned. The course of learning is affected by intelligence, in Spearman’s view, but it was not the thing in itself. Spearmanian intelligence was a measure of a person’s capacity for complex mental work.
    Meanwhile, other testers in Europe and America continued to refine mental measurement. By 1908, the concept of
mental level
(later called
mental age
) had been developed, followed in a few years by a slightly more sophisticated concept, the intelligence quotient. IQ at first was just a way of expressing a person’s (usually a child’s) mental level relative to his or her contemporaries. Later, as the uses of testing spread, IQ became a more general way to express a person’s intellectual performance relative to a given population. Already by 1917, soon after the concept of IQ was first defined, the U.S. Army was administering intelligence tests to classify and assign recruits for World War I. Within a few years, the letters “IQ” had entered the American vernacular, where they remain today as a universally understood synonym for intelligence.
    To this point, the study of cognitive abilities was a success story, representing one of the rare instances in which the new soft sciences were able to do their work with a rigor not too far short of the standards of the traditional sciences. A new specialty within psychology was created, psychometrics. Although the debates among the psychometricians were often fierce and protracted, they produced an expanded understanding of what was involved in mental capacity. The concept of
g
survived, embedded in an increasingly complex theory of the structure of cognitive abilities.
    Because intelligence tests purported to test rigorously an important and valued trait about people (including ourselves and our loved ones), IQ also became one of the most visible and controversial products of social science. The first wave of public controversy occurred during the first decades of the century, when a few testing enthusiasts proposed usingthe results of mental tests to support outrageous racial policies. Sterilization laws were passed in sixteen American states between 1907 and 1917, with the elimination of mental retardation being one of the prime targets of the public policy. “Three generations of imbeciles are enough,” Justice Oliver Wendell Holmes declared in an opinion upholding the constitutionality of such a law. 9 It was a statement made possible, perhaps encouraged, by the new enthusiasm for mental testing.
    In the early 1920s, the chairman of the House Committee on Immigration and Naturalization appointed an “Expert Eugenical Agent” for his committee’s work, a biologist who was especially concerned about keeping up the American level of intelligence by suitable immigration policies. 10 An assistant professor of psychology at Princeton, Carl C. Brigham, wrote a book entitled
A Study of American Intelligence
using the results of the U.S. Army’s World War I mental testing program to conclude that an influx of immigrants from southern and eastern Europe would lower native American