Schooling, intelligence, and income.

In this article, the authors examined the evidence for linkages among 3 variables: schooling, intelligence, and income. They concluded that intelligence and schooling have a bidirectional relationship, with each variable in-fluencing variations in the other. Moreover, changes in both schooling and intelligence influence variations in economic outcomes. Although any single study of the interdependency of these 3 variables can be criticized on the grounds that the data are correlational--and conse-quently are open to alternative interpretations--when viewed together, the evidence for their linked causality is quite convincing: Each increment in school attendance appears to convey significant increases not only in eco-nomic and social returns but also in psychometric ntelli-gence. Thus, the value of schooling appears to extend