Guilford dimensions of intelligence
three dimensions of intelligence postulated by Joy Paul Guilford to underlie individual differences in scores on intelligence tests, namely, contents, operations, and products. Each mental ability represents a combination of these three facets. For example, performance on a verbal-analogies test would represent a combination of cognition (operation) of verbal (content) relations (product). The number of mental abilities initially proposed by Guilford was 120; this was later increased to 150. The validity of this theory was subsequently called into question by the work of U.S. psychologist John L. Horn (1928–2006), which suggested that the existence of the proposed factors is not supported by research results. See also structure of intellect model.