Researchers interested in intelligence testing seek to determine what factors, or dimensions, make up intelligence, and how they change with age. They are interested in how cognitive development can be measured so that scores are useful for predicting future academic achievement, career attainment, and other aspects of intellectual success.

The psychometric approach to cognitive development is the basis for the wide variety of intelligence tests used to assess individual differences in children's mental abilities. Factor analysis emerged as a statistical method to identify the mental abilities that contribute to successful performance on intelligence tests. However, factor analysts have been criticized for devoting too much attention to identifying factors and too little to clarifying the cognitive processes that underlie them. To overcome the limitations of factor analysis, some researchers have combined psychometric and information-processing approaches and conduct componential analyses of children's test scores. Sternberg's triarchic theory of intelligence extends these efforts. Gardner's theory of multiple intelligences identifies eight distinct domains of ability, each defin ed by unique processing operations.

A wide variety of tests are currently available to assess children's intelligence. Accurately measuring the intelligence of infants is an especially challenging task. IQs obtained after age 6 show substantial correlational stability. IQ is an effective predictor of scholastic performance, occupational attainment, and certain aspects of psychological adjustment.

The relationship of socioeconomic status to intellectual development has sparked the IQ nature-nurture debate. Heritability estimates support a moderate role for heredity in accounting for individual differences in IQ. However, they cannot be used to explain ethnic and social-class differences in test scores. Shared and nonshared environmental influences also contribute to individual differences in intelligence.

Family attitudes toward intellectual success and academic performance are powerful predictors of academic success. Research on early intervention programs indicates that lasting benefits occur in school adjustment and in the ability to meet basic educational requirements. Conceptions of giftedness have recently expanded to include creativity.