Bryan Caplan's new post is titled "Intelligence Makes People Think Like Economists: Further Evidence." The claim from the Duarte, Haidt et al. article he quotes is that "economic conservatism" and IQ are positively correlated. The comments on my FB make me think I should have stressed this more, as some seem to have run away with the idea that high IQ folks tend to frame questions in the same sort of way as academic economists. Now that's a pretty debatable interpretation of "economic conservatism". Maybe I'll get around to checking how the article operationalises this concept some time, or maybe someone else will let me know.
Bryan's post provides the 7 relevant references given in the article's mini literature review.
I think leftism is often seen as the province of intelligent people, and dispelling that notion with sheer IQ data might do a lot of good. True, people will get to say "ad hominem". And, of course, that people are more likely to think X the smarter they are does not guarantee that X is true. Still, I think it's evidence for X. How strong this evidence is depends on a number of other contentious issues, though.