Researchers showed students photos of candidates in a very well designed study (abstract). Based on their choices from the photos alone, they predicted the outcomes of the elections with about 70% accuracy.
Asking participants to deliberate and make a good judgment dramatically increased the response times and reduced the predictive accuracy of judgments relative to both judgments made after 250 ms of exposure to the faces and judgments made within a response deadline of 2 s.
In other words, thinking about the selection reduced their ability to predict the results of the election. Get it?
In this earlier study, scientists used some unscpecified brain scan to observe subjects engaged in thinking about politics. Instead of involving areas used in logic, the subjects seemed to activate their pleasure centers by reaching a conclusion that agreed with their preconceptions.
Researchers asked staunch party members from both sides to evaluate information that threatened their preferred candidate prior to the 2004 Presidential election.
...
"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."
...
The test subjects on both sides of the political aisle reached totally biased conclusions by ignoring information that could not rationally be discounted, Westen and his colleagues say.
I intended to write this as solely a blog post, but I just can't resist posting it to CE. 
FTW!
