IQ and stratification: An empirical evaluation of Herrnstein and Murray's social change argument

Abstract

A state-level index of the conditions that Herrnstein and Murray suggest tightened the relationship between IQ and status in the past century as well as a measure of "credentialing by examination" are used to try to explain interstate variation in the association between IQ and status attainment circa 1990. The results contradict Herrnstein and Murray's interpretation and provide support for an alternative credentialing argument. The more a state uses written, IQ-like examinations as screening devices for occupational access, the stronger the relationship between IQ and income. Thus, rather than higher IQ leading to status attainment because it indicates skills needed in a modern society, IQ may reflect the same test-taking abilities used in artificial screening devices by which status groups protect their domains.