Predicting political beliefs with polygenic scores for cognitive performance and educational attainment
Author links open overlay panelTobias Edwards, Alexandros Giannelis, Emily A. Willoughby, James J. LeeRedirecting Get rights and content
Highlights
- •
Within-families, intelligence predict left-wing beliefs.
- •
DNA-based predictors of IQ also predict political beliefs within families.
- •
Our results imply that being genetically predisposed to be smarter causes left-wing beliefs.
Within-families, intelligence predict left-wing beliefs.
DNA-based predictors of IQ also predict political beliefs within families.
Our results imply that being genetically predisposed to be smarter causes left-wing beliefs.
Abstract
Intelligence is correlated with a range of left-wing and liberal political beliefs. This may suggest intelligence directly alters our political views. Alternatively, the association may be confounded or mediated by socioeconomic and environmental factors. We studied the effect of intelligence within a sample of over 300 biological and adoptive families, using both measured IQ and polygenic scores for cognitive performance and educational attainment. We found both IQ and polygenic scores significantly predicted all six of our political scales. Polygenic scores predicted social liberalism and lower authoritarianism, within-families. Intelligence was able to significantly predict social liberalism and lower authoritarianism, within families, even after controlling for socioeconomic variables. Our findings may provide the strongest causal inference to date of intelligence directly affecting political beliefs.Section snippets
Sample
The Sibling Interaction and Behavior Study (SIBS) recruited families between 1998 and 2003 (McGue et al., 2007). State birth records and records from adoption agencies allowed for a representative sample of adoptive and biological families to be recruited. Statistics used in this study were taken at intake or follow-up 3 lasting from 2017 to 2023. The sample and political-attitude scales have previously been used and described in Willoughby, Giannelis, Ludeke, Klemmensen, et al. (2021), so ourRegressions of political beliefs on IQ
Fig. 1 is a forest plot showing the effects of phenotypic and genotypic IQ on our scales of political beliefs, using different control variables. All estimates, standard errors and relevant diagnostic test statistics for the plot are presented in the supplementary spreadsheets. IQ and political beliefs are standardized. Table 4 shows the full regression models for the composite political scale.Across all political beliefs, phenotypic IQ significantly predicts views in a left-wing direction. The