Intelligence: Knowns and Unknowns
Report of a Task Force established by the Board of Scientific Affairs of the American Psychological Association Released August 7, 1995
Ulric Neisser, PhD, Chair; Emory University
As presented by STALKING THE WILD TABOO
[A slightly edited version was published in the American Psychologist, Feb 1996. Official Journal of the APA] ...
I. CONCEPTS OF INTELLIGENCE
Individuals differ from one another in their ability to understand complex ideas, to adapt effectively to the environment, to learn from experience, to engage in various forms of reasoning, to overcome obstacles by taking thought. Although these individual differences can be substantial, they are never entirely consistent: a given person's intellectual performance will vary on different occasions, in different domains, as judged by different criteria. Concepts of "intelligence" are attempts to clarify and organize this complex set of phenomena. Although considerable clarity has been achieved in some areas, no such conceptualization has yet answered all the important questions and none commands universal assent. Indeed, when two dozen prominent theorists were recently asked to define intelligence, they gave two dozen somewhat different definitions (Sternberg & Detterman, 1986). Such disagreements are not cause for dismay. Scientific research rarely begins with fully agreed definitions, though it may eventually lead to them. This first section of our report reviews the approaches to intelligence that are currently influential, or that seem to be becoming so. Here (as in later sections) much of our discussion is devoted to the dominant psychometric approach, which has not only inspired the most research and attracted the most attention (up to this time) but is by far the most widely used in practical settings. Nevertheless, other points of view deserve serious consideration. Several current theorists argue that there are many different "intelligences" (systems of abilities), only a few of which can be captured by standard psychometric tests. Others emphasize the role of culture, both in establishing different conceptions of intelligence and in influencing the acquisition of intellectual skills. Developmental psychologists, taking yet another direction, often focus more on the processes by which all children come to think intelligently than on measuring individual differences among them. There is also a new interest in the neural and biological bases of intelligence, a field of research that seems certain to expand in the next few years. In this brief report, we cannot do full justice to even one such approach. Rather than trying to do so, we focus here on a limited and rather specific set of questions: •What are the significant conceptualizations of intelligence at this time? (Section I) •What do intelligence test scores mean, what do they predict, and how well do they predict it? (Section II) •Why do individuals differ in intelligence, and especially in their scores on intelligence tests? Our discussion of these questions implicates both genetic factors (Section III) and environmental factors (Section IV). •Do various ethnic groups display different patterns of performance on intelligence tests, and if so what might explain those differences? (Section V) •What significant scientific issues are presently unresolved? (Section VI) Public discussion of these issues has been especially vigorous since the 1994 publication of Hermstein and Murray's The Bell Curve, a controversial volume which stimulated many equally controversial reviews and replies. Nevertheless, we do not directly enter that debate. Hermstein and Murray (and many of their critics) have gone well beyond the scientific findings, making explicit recommendations on various aspects of public policy. Our concern here, however, is with science rather than policy. The charge to our Task Force was...