“Predicting Political Beliefs With Polygenic Scores for Cognitive Performance and Educational Attainment”, Tobias Edwards, Alexandros Giannelis, Emily A. Willoughby, James J. Lee2024-04-06 (, , , )⁠:

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 statistically-significantly predicted all 6 of our political scales.

Polygenic scores predicted social liberalism and lower authoritarianism, within-families. Intelligence was able to statistically-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.

[Keywords: causal inference, genetics, intelligence, political belief, polygenic score]

…As of writing, one published paper has found that polygenic scores can predict political beliefs. Ahlskog2023 found a polygenic score for educational attainment had a positive effect on social liberalism and a negative effect on economic conservatism, using family fixed effects. This was interpreted as evidence for education affecting political beliefs. We focus specifically on the psychological trait of intelligence, measured more precisely, with the cognitive performance polygenic score from Becker et al 2021. Cognitive performance is simply an euphemism for intelligence.

Figure 1: Intelligence and political belief. The data points represent the regression betas of IQ. The 95% confidence intervals are clustered at the family level. Estimates are colored in if they are statistically-significant after a Benjamini-Hochberg correction for multiple testing at p < 0.05. Models are labeled by their most important right-hand-side variables. In the phenotypic models the estimates are obtained from ordinary least squares; in the genotypic models, two-stage least squares (2SLS) with the CP polygenic score as the instrument. FE stands for family fixed effects. Models using mid-parent PGS control for the mean polygenic score of the parents. Putative mediators include years of education and the logarithm of income. All models include controls for sex, age, an East Asian dummy variable and the first 5 genetic principal components, interacted with the East Asian variable.
Figure 2: EA polygenic score and political belief. The data points represent the regression betas of the EA polygenic score, standardized to have a standard deviation of one. The 95% confidence intervals are clustered at the family level. Estimates are colored in if they are statistically-significant after a Benjamini-Hochberg correction for multiple testing at p < 0.05. Models are labeled by their most important right-hand-side variables; EA is the EA polygenic score, and mid-parent PGS is the mean EA polygenic score of the parents. Putative mediators include years of education and log income. All models include controls for sex, age, an East Asian dummy variable and the first 5 genetic principal components, interacted with the East Asian variable.

…Because the EA polygenic score is an indicator of intelligence and other mental traits, it is unclear through which psychological traits the score affects political beliefs. We perform an additional set of models controlling for IQ. In these models, the EA polygenic score’s point estimate remains similar to earlier estimates, but confidence intervals are too large to be informative regarding whether part of the polygenic score’s explanatory power comes from non-cognitive traits.

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Predicting Political Beliefs With Polygenic Scores for Cognitive Performance and Educational Attainment