Skeptico has a post up concerning recent research into the thought processes behind political decision making. According to a Live Science article about the study:

Researchers asked staunch party members from both sides to evaluate information that threatened their preferred candidate prior to the 2004 Presidential election. The subjects' brains were monitored while they pondered.

...

"We did not see any increased activation of the parts of the brain normally engaged during reasoning," said Drew Westen, director of clinical psychology at Emory University. "What we saw instead was a network of emotion circuits lighting up, including circuits hypothesized to be involved in regulating emotion, and circuits known to be involved in resolving conflicts."

As Richard points out, this isn't really shocking (in fact it explains a lot of what we see not only in politics but in many aspects of life), but it is neat to see the data backing it up. Also interesting is what the scans show after the contradictory information is rationalized — defending your beliefs "successfully" (rationally or irrationally) is, quite literally, a "high." It pretty handily explains not only a large number of the frustrating political discussions we've had in our lives, but also many other frustrating exchanges in other fields of study.

Check out the post from Skeptico, as well as the article.

Hmmm This might also offer some explanation why people with mild depression are more objective than others, they don't get the same internal emotional response.

Where's the paper?

Looks like a draft of the paper is available on request, "The neural basis of motivated reasoning": http://www.psychsystems.net/lab/type4.cfm?id=400§ion=4&source=200&source2=1

Nice! Thanks, Ron.

Great post. This problem of "people happily defending their own beliefs" (whether rationally or not) is one of the biggest obstacles to human progress. I can't stand the fact that only about 2% of my acquaintances are capable of having a rational discussion/debate in which both people are seeking the truth--as opposed to the other 98% of debates in which each is simply trying to prove to the other that his own opinion is correct. Around dinner tables now, it's either tell jokes or tell stories about your day. What happened to thought-provoking conversation? People started taking it personally. That's what happened. Somebody needs to tell them that learning something new is PROGRESS--not something of which to be ashamed.

In my experience, very few people are capable of listening to opposing points of view with anything approaching an open mind. You shout out your opinion, I'll shout out mine, and in a few minutes we'll both leave, neither of us any wiser or more educated than when we started. Hell, people like Bill O'Reilly have made a career out of this sort of "debate," so it's hardly surprising that it's so prevalent. Sad, isn't it?