David Pizarro gives a great TED Talk on the politics of disgust:

What does a disgusting image have to do with how you vote? Equipped with surveys and experiments, psychologist David Pizarro demonstrates a correlation between sensitivity to disgusting cues -- a photo of feces, an unpleasant odor -- and moral and political conservatism. (Filmed at TEDxEast.)

David Pizarro is a psychologist interested in how certain emotions (disgust, fear, anger) affect our moral judgment.

This reminds me of Dan Ariely's book, Predictably Irrational. We like to believe we're logical, rational animals, but we're far from it.