American dreams

[tigerfort]

Following on from various coverage of the current American pre-presidential excitement, I was interested to read recently (in Counting Sheep, Paul Martin's excellent book on the 'science and pleasures of sleep') that Republican supporters were three times more likely to experience nightmares than their less conservative Democratic opponents. Even the non-nightmare dreams that Republicans reported were generally more frightening and more aggressive in content.

So do paranoia and aggressive instincts cause Republican voting, or are they its effect?