Are conservatives just stupid?
Provocative thread title aside, the research on the lower intelligence of conservatives is pretty well replicated. It also falls in line with distributions we see with other statistics that serve as rough proxies for intelligence such as education levels, occupation, and even geographic location. The addendum here is that a lot of the identification may fall along social rather than fiscal ideology; lots of smart people are fiscally conservative and socially liberal.
It's possible that some of the variance can be explained by the fact that conservatives tend to be older, and therefore on the wrong side of the Flynn effect. But it's also possible that the Flynn effect is a reason for the greater liberalism of young people; they're just smarter.
Could the great divide in politics be explained by differences in cognition?