More than g: Verbal and performance IQ as predictors of socio-political attitudes

Abstract

Measures of intelligence predict socio-political attitudes and behaviors, such as liberalism, religiosity, and voter turnout. Little, however, is known about which cognitive abilities are responsible for these relationships. Employing several cohorts from the Minnesota Center for Twin and Family Research, we test the predictive performance of different broad abilities. Using multiple regression to compare verbal and performance IQ from Wechsler intelligence tests, we find verbal IQ more strongly predicts voter turnout, civic engagement, traditionalism, and measures of ideology. On average, the correlation between verbal IQ and our socio-political attitudes is twice as large as that of performance IQ. The same pattern appears after controlling for education and after performing the analysis within sibling pairs. This implies that the relationship cannot be entirely mediated through education, nor entirely confounded by upbringing. Positive and negative controls are employed to test the validity of our methodology. Importantly, we find verbal and performance IQ to be equally predictive of the ICAR-16, a distinct measure of general intelligence. The results imply that variation in cognitive abilities, which are orthogonal to general intelligence, influence socio-political attitudes and behaviors. The role of verbal ability in influencing attitudes may help to explain the ideological leanings of specific occupations. Its association with turnout and civic engagement suggests that those with a verbal tilt may have greater influence over politics and society.