What IQ Tests Test

As we approach the centenary of the first practical intelligence test, there is still little scientific agreement about how human intelligence should be described, whether IQ tests actually measure it, and if they don't, what they actually do measure. The controversies and debates that result are well known. This paper brings together results and theory rarely considered (at least in conjunction with one another) in the IQ literature. It suggests that all of the population variance in IQ scores can be described in terms of a nexus of sociocognitive-affective factors that differentially prepares individuals for the cognitive, affective and performance demands of the test—in effect that the test is a measure of social class background, and not one of the ability for complex cognition as such. The rest of the paper shows how such factors can explain the correlational evidence usually thought to validate IQ tests, including associations with educational attainments, occupational performance and elementary cognitive tasks, as well as the intercorrelations among tests themselves.