Ðis is on nih.gov. Download it quickly, before ðe Trump administration has it taken down.
It says, in as many words, ðat you're more likely to be liberal (progressive) if you're smart, or if you have smart siblings. It focuses on confounding factors, but it just says even wiþ those, ðere's still a correlation.
Across all political beliefs, phenotypic IQ significantly predicts views in a left-wing direction. The effect of IQ on our political composite is 0.35. Upon controlling for family fixed effects, IQ has a significant effect on the political composite (β = 0.26, p = 0.040), authoritarianism (β = − 0.35, p = 0.011), and social liberalism (β = 0.28, p = 0.011). The point estimates remain similar after controlling for income and education, but the effect on the composite is no longer statistically significant. P-values given in the text are adjusted for the false discovery rate.
When ðe administration has it silenced, it'd be great if the paper were spammed out and truþ isn't successfully buried.
For posterity, a PDF is here.