Average state IQ, state wealth and racial composition as predictors of state health statistics: Partial support for ‘ g’ as a fundamental cause of health disparities

Abstract

This study examined the degree to which differences in average IQ across the 50 states was associated with differences in health statistics independent of differences in wealth, health care expenditures and racial composition. Results show that even after controlling for differences in state wealth and health care expenditures, average IQ had sizeable positive associations with a wide range of positive health indicators, and sizeable negative associations with a wide range of state health problems. Consistent with Gottfredson's (2004) [ Journal of Personality and Social Psychology, 86, 174−199.] hypotheses, some of the apparent associations between racial composition and health outcomes were accounted for by IQ differences. When IQ was controlled, some of the relationships between racial composition and health outcomes reversed signs suggesting an advantage for minorities. However, even after controlling for average IQ and wealth factors, racial composition continued to be associated with some of the health statistics examined. Overall, the results partially confirmed that g does account for a significant portion of the variance many state health outcomes, but socio-economic factors and racial composition appear to also have important relations with some specific health outcomes.