According to this substantial study recently published in Psychological Scien…

According to this substantial study recently published in Psychological Science, "lower general intelligence (g) in childhood predicts greater racism in adulthood, and this effect was largely mediated via conservative ideology.". As the Daily Mail summarises, right-wingers are less intelligent than left wingers.

http://pss.sagepub.com/content/23/2/187.full.pdf+html