What is Intelligence?

Despite the immense importance claimed for it, precisely what intelligence is has been the subject of a great deal of uncertainty and debate. This may relate to a certain disinterest in theory that has characterized testing. The intellectual center of testing lies in the branch of psychology known as psychometrics, a term that means simply the measurement of mental phenomena. Several psychologists have remarked on a gap that has opened up between psychometrics and another major branch of the discipline, cognitive psychology. Cognitivists, who trace their pedigree from Wilhelm Wundt, have been interested in determining the basic processes of mind and behavior in general. Differences between individuals are of marginal interest in this research program. Psychometricians, however, descend intellectually from biologists—especially Darwin—via Galton. Their attention has been directed precisely to individual differences, originally in an effort to trace the operation of natural selection in the evolutionary development of our own species.^[8] But this theoretical orientation waned as psychometricians increasingly concentrated their attention on the practical applications of testing. A number of psychologists have criticized this development, claiming that psychometricians have accommodated themselves to demands from the public for simple solutions to complex problems by developing tests that claim to predict who is likely to succeed in various educational programs, military assignments, jobs, and so on. The result has been a profusion of tests with little substantial grounding in psychological theory.^[9] The situation has become serious enough that Oscar Buros, who founded the Mental Measurements Yearbook as a means of reviewing and providing some quality control for the multitude of mental tests now available, stated in both the 1972 and 1978 editions that "at least half

of the tests currently on the market should never have been published."^[10]

In 1923, Harvard psychologist Edwin Boring set out to cut the Gordian knot over what intelligence really is by calling it simply the human capacity that is measured by intelligence tests. This is termed an "operational" definition—the practice of defining something in terms of the procedures used to measure it. "Intelligence," as Boring put it, "is what the tests test."^[11] This definition has been reiterated several times since.^[12]

At first blush, the concept of intelligence held by the general public seems quite different from the operational definition. The popular view, seldom precisely articulated, focuses on general mental ability; perhaps it is best stated as the ability to learn. This is fleshed out by associating the general ability called "intelligence" with three attributes: (1) it is a single thing; (2) it comes in varying quantities, and different people have different amounts of it; and (3) the amount of intelligence possessed by each individual is fixed for life. Although the popular or conventional concept of intelligence does not have the classic form of an operational definition ("intelligence is what intelligence tests test"), I argue that it nevertheless is operational in essence because the attributes commonly associated with intelligence stem from testing practices. First, the idea that intelligence is a single thing is rooted in the fact that the results of intelligence tests are often expressed on a single scale, such as IQ, even when the test itself consists of several distinct parts. Where there is a single score, it is widely assumed that some single thing must exist to which that score refers. The second attribute—that intelligence is quantitative, and that some people have more of it than others—derives from the practice of reporting intelligence test scores on numerical scales. Only quantitative phenomena may be expressed in numbers. And when those numbers vary from one person to another, so must the amount of intelligence that the numbers represent. Finally, the notion that the amount of intelligence possessed by each individual is fixed for life stems from the belief that intelligence tests measure not what one already knows but one's ability to learn. It is commonly believed that how much an individual actually learns depends on opportunity, mo-

tivation, and ability. Opportunity and motivation may vary at different times in the individual's life, but sheer ability to learn is generally considered to be a constant. It is hard-wired in the person. Hence each individual's intelligence is considered to be fixed by heredity.^[13]

This conventional or popular notion of intelligence has achieved the status of a bedrock assumption. It is taken by most people in our society to describe a simple fact of nature. I wish to dispute that point of view. I have just argued that the popular concept of intelligence results from intelligence testing. And I argued earlier (chap. 2) that all testing traffics in representations and that any representation is not a given in nature but is a product of cultural conventions. By this reasoning, the "intelligence" that is represented in intelligence tests is not some independently existing natural phenomenon but a reality as construed by culture. It could very well be—and in fact is—conceptualized differently in other cultural traditions.^[14]

An important reason why the particular concept of intelligence that reigns in our society has gained ascendancy is that intelligence tests have made it possible to measure, evaluate, and make a variety of selections among the masses conveniently and economically. Nevertheless, as I will attempt to demonstrate, that notion of intelligence has been responsible for a great deal of confused thinking, unjust policies, and human damage.