Political Brain
In a 2004 study by Drew Westen partisan Democrats and Republicans were presented with threatening information about Bush and Kerry, while researchers watched what their brains did in response.
Subjects were first presented a slide showing something good about the subject’s candidate, then the next slide presented the candidate contradicting himself. The subjects were then asked to consider whether or not there was a contradiction.
The brain regions that are active during reasoning tasks were mostly inactive. What turned on instead were circuits involved in emotion, particularly distress, and emotional regulation.
“Emotion Trumps Logic in the Voting Booth,” by Terrence McNally