Overview

In 1995, a task force of the American Psychological Association (APA) headed by psychologist Ulric Neisser published a report entitled Intelligence: Knowns and Unknowns which intended to present a summary of the findings of scientific research regarding intelligence, which also commented upon the topic of race and intelligence.^[7] According to this report, psychometric testing, despite being one of the most fruitful approaches to studying intelligence, has yet to produce answers to many questions regarding intelligence. Though psychometricians have devised ways to measure the distinct yet intercorrelated abilities believed to play an important role in the development of intelligence, the correlations between those abilities remain largely unclear. As intelligence test scores correlate moderately well with measures of educational success, it is apparent that such tests measure important skills. However, noted the authors, educational achievement is not primarily determined by intelligence, though intelligence test scores do correlate significantly with occupational status later in life.
The APA report further noted that, while both genetic and environmental variables are involved in the manifestation of intelligence, the role of genetics has been shown to increase in importance with age. Why this happens in not yet understood, and the question as to what role the environment plays in this increase remains unanswered. Nonetheless, there are several important environmental factors which are known to affect the development of intelligence, such as formal education and general health. The much-discussed "Flynn effect", which refers to the striking worldwide mean IQ increase of 15+ points over the last 50 years, may be the result of similar environmental factors such as improved nutrition, cultural changes, improvement in the administration of tests, changes in educational practices or some other hitherto unrecognized factor.
On the topic of race and intelligence, the APA task force wrote that, as the measured differences in intelligence between various ethnic groups is the result of complex patterns, any conclusions which require broad generalizations run the risk of oversimplifying the issue as well as misrepresenting the available data. At the same time, intelligence test scores in some minority populations are reasonably good indicators of educational achievement levels in later life. The long-standing 15+/- point difference between the intelligence test scores of African Americans and White Americans, though it might have narrowed somewhat in recent years, remains unaccounted for despite proposed explanations claiming systematic bias, differences in culture or socioeconomic status (SES), or genetics as the sole underlying cause.^{[citation needed]}