A recent study shows that extreme partisans don't use rational parts of the brain when processing political information:
Is political persuasion mostly useless? Is the percentage of people essentially immune to rational argument about political things increasing? [...]
At Emory University, psychologist Drew Westen and his team conducted what they believe is the first study of "the neural basis of any form of political decision making." They did this by using brain imaging to study people as they processed political information during the 2004 campaign.
To rape and pillage fine science with rough paraphrasing, this is what they discovered: When 30 self-described partisans were presented with contradictory quotes about the candidates (President Bush supporting, then denouncing Ken Lay; Sen. John Kerry supporting, then denouncing a Social Security overhaul), it was the portions of the brain that process emotion, not rational thinking, that became active. "The thinking caps went off and the feeling caps went on," is how Westen put it to me.
Normally, Westen says, a brain faced with contradictory information will fire up the zones where reason or rational thought happens. The 30 partisans in this study were presented with contradictory quotes from Bush and Kerry, but also from Hank Aaron, Tom Hanks and the writer William Styron. They processed the information about the non-politicians with the reasoning centers of the brain. It was politics that short-circuited them. ("This is your brain; this is your brain on politics.")
It would be reasonable to ask whether all brains — not just partisan ones — respond to political information emotionally. Westen says the answer is clearly no, that research does demonstrate that centrists or independents are more able to process rational and non-emotional political information.
But Westen's MRIs show that is clearly not the case with political contradictions processed by a partisan brain. That process is almost entirely emotional, heating up regions of the brain that govern things like forgiveness, relief and pleasure. The reasoning zones stayed ice cold.
Your response, I imagine, is "duh." Partisans are emotional; stop the presses, get me rewrite. Perhaps. But I find the graphic clarity of colorful brain scans to be sobering. It’s one thing to know that some people get obnoxious during political arguments; it’s another thing to see that 30 adult men who read candidates' quotes while strapped down in MRI machines didn’t even fire up the thinking parts of their brains.
According to Arthur Brooks, a professor at the business school at Syracuse University, the number of partisan brains is increasing. And they may be becoming more partisan; more precisely, they seem to hate their opponents more.
I don't know. So far as I can tell, the only thing that prevents progressives from rationally responding to contradictions uttered by the evil mignons of the right are the sheer numbers of them. One's thought processes can only handle so much cretinous malignant nonsense before they fitz out in outrage.