Presents findings of a task force established by the American Psychological Association to report on the issues of what is known and unknown about intelligence. Significant conceptualizations of intelligence are reviewed, including the psychometric approach, theories of multiple forms of intelligence, cultural variations, theories of developmental progressions, and biological approaches. The meaning of intelligence test scores, what they predict, and how well they predict intelligence is discussed. Genetic factors and intelligence, focusing on individual differences, conventional IQ tests, and other tests intended to measure cognitive ability, are described. Environmental factors such as social and biological variables are discussed, and sex and ethnic group differences are addressed. Recommendations for future research are presented. (PsycINFO Database Record (c) 2012 APA, all rights reserved)