How much does schooling influence general intelligence and its cognitive components? A reassessment of the evidence.

This is a review of the relationship between schooling, IQ, and the cognitive processes presumed to underpin IQ. The data suggest that much of the causal pathway between IQ and schooling points in the direction of the importance of the quantity of schooling one attains (highest grade successfully completed). Schooling fosters the development of cognitive processes that underpin performance on most IQ tests. In western nations, schooling conveys this influence on IQ and cognition through practices that appear unrelated to systematic variation in quality of schools. If correct, this could have implications for the meaning one attaches to IQ in screening and prediction as well as for efforts to influence the development of IQ through changes in schooling practices