Academic journal article
By Schlinger, Henry D.
The Psychological Record , Vol. 53, No. 1
Few topics have sparked such heated debate within the academic community and society at large as that of intelligence and intelligence testing. Some of the contentious issues in the debate include the very definition of intelligence, the controversy concerning IQ and race, the ever present nature-nurture problem (Weinberg, 1989), and even the question of whether intelligence exists (Howe, 1990). The debate was reignited most recently by the publication in 1994 of The Bell Curve: Intelligence and Class Structure in American Life by Richard J. Herrnstein and Charles Murray. The sturm und drang created by the publication of this book was, among other things, the motivation behind the creation of a task force in 1995 by the Board of Scientific Affairs of the American Psychological Association to prepare an authoritative report on the current status of research on intelligence and intelligence testing. The flurry of response generated by The Bell Curve, both in the academic community and in the media, also prompte d a letter to the Wall Street Journal in December, 1994, in which 50 professors "all experts in intelligence and allied fields" signed a statement, titled "Mainstream Science on Intelligence." (1) The purpose of this statement was to respond to the public outcry over the suggestions and social implications of The Bell Curve by outlining "conclusions regarded as mainstream among researchers on intelligence, in particular, on the nature, origins, and practical consequences of individual and group differences in intelligence" ("Mainstream Science on Intelligence," 1994).
One of the reasons for the persistent concern about intelligence is that intelligence tests have been used to support nativistic theories in which intelligence is viewed as a qualitatively unique faculty with a relatively fixed quantity. Historically, proponents of nativistic theories have succeeded in persuading those with political power that standardized tests reliably measure intelligence; and these tests have been used to make important decisions about vast numbers of individuals including immigrants, U.S. soldiers during the first World War, normal school children, and the developmentally disabled. Not surprisingly, there exists a substantial literature documenting the history of the intelligence testing movement (e.g., Bolles, 1993; Fancher, 1985; Gould, 1981; Herrnstein & Murray, 1994; Kamin, 1974).
Background: General Intelligence
Although many people have contributed to the conception of intelligence as a unitary, qualitatively unique trait, we may trace its origin in the history of the intelligence testing movement to the British psychologist and statistician Charles Spearman. When Spearman factor analyzed scores on different tests of intelligence, including his own Galtonian-inspired sensory acuity tests, as well as those designed by Binet and Simon, he discovered that not only were the correlations positive, but they fell into a roughly hierarchical pattern with the highest correlations on tests that Spearman believed required higher level skills, such as abstract thinking. For Spearman, these positive intercorrelations provided evidence of a common underlying factor that tied them all together; he called this factor g for general intelligence (Spearman, 1904, 1927). Crinella and Yu (2000) explain: People who are proficient at solving a given problem tend to be proficient at solving others; those less capable of solving that proble m tend to be less capable of solving others. The psychometric representation of this phenomenon is the general intelligence or g factor, obtained whenever scores on a battery of diverse problem solving tests are factor analyzed. (p. 299)
Thus g factor, or simply g as it is called, is a numerical outcome-an algebraic factor--resulting from a complex series of statistical manipulations, called factor analysis. Although Spearman believed that different types of skills required their own type of intelligence, which he called s for specific factors, he still viewed g as the most important factor. …