Political differences may lie in different fear responses

From the Boston Globe:

... researchers found a strong correlation between subjects' political attitudes and their physiological responses to threat. People who showed more "blink startle" and perspiration after a threatening stimulus tended to cluster on the right politically. They advocated capital punishment, school prayer, and defense spending, and they supported the Iraq war.

In contrast, liberals - who supported "less protectionist" policies such as gun control, open immigration, and increased foreign aid - showed significantly less physical response to the threatening stimuli. ... And the degree to which a person was startled by threatening stimuli indicated how much he or she advocated policies that protect society from external and internal threats such as wars and crime. [¶ ¶]

When researchers compared subjects' physical responses with their political opinions, they found a striking correlation. "It was clear," Hibbing said, "that some individuals have certain central-nervous-system reactions in the part of the brain involved in fear - there's a genetic basis for this - and this brain activity underlies both their startle response and their political views."

Eve LaPorte, Born to Party, Boston Globe, Nov. 2, 2008 (emphasis added; hat tip: Hacker News).