Brain says, white or black

People often discount any information that threatens their beliefs

People who see the world in black and white rarely seem to take in information that could undermine their positions. Psychological experiments in recent years have shown that people are not evenhanded when they process information, even though they believe they are. When people are asked whether they are biased, they say no. But when asked if they think other people are biased, they say yes.

Partisans who watch presidential debates invariably think their guy won. When talking heads provide opinions after the debate, partisans regularly feel the people with whom they agree are making careful, reasoned arguments, whereas the people they disagree with sound like they have cloth for brains. Unvaryingly, partisans also believe partisans on the other side are far more ideologically extreme than they actually are, said Stanford University psychologist Mark Lepper.

Although it is satisfying to think your side is right and the other side consists of morons, the systematic errors that can be documented in partisan perception suggest something deeper than deliberate tunnel vision. What explains these distortions in perception?

In an experiment that politicos might want to note closely, researchers recently plopped 10 Republicans and 10 Democrats into scanners that measure changes in brain-blood oxygenation. Such changes are thought to be linked to increases or decreases in particular areas of brain activity. Each of the partisans was repeatedly shown images of President George W Bush and 2004 Democratic challenger John Kerry. When Republicans saw Kerry or Democrats saw Bush there was increased activation in brain areas called the dorsolateral prefrontal cortex and the anterior cingulate cortex, which is in the middle of the head. Both these regions are involved in regulating emotions.

More straightforwardly, Republicans and Democrats also showed activation in two other brain areas involved in negative emotion, the insula and the temporal pole. It makes perfect sense why partisans would feel negatively about the candidate they dislike, but what explains the activation of the cognitive regulatory system?

Turns out, rather than turning down their negative feelings, partisans turn up their negative emotional response when they see a photo of the opposing candidate, said Jonas Kaplan, a psychologist at the University of California at Los Angeles. In other words, without knowing it, the partisans were jealously guarding against anything that might lower their antagonism.

Turning up negative feelings, of course, is a good way to make sure your antagonism stays strong and healthy. 8216;8216;My feeling is, in the political process, people come to decisions early on and then spend the rest of the time making themselves feel good about their decision,8217;8217; Kaplan said. He said partisans have a strong interest in feeling poorly about the candidate they are not going to vote for as that cements their belief that they are doing the right thing. 8216;8216;Democrats looking at Bush may have some positive feelings about the fact he is their leader, so the process of convincing yourself this is someone you don8217;t like when you intend not to vote for him makes sense,8217;8217; he said.

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The result reflects a larger phenomenon in which people routinely discount information that threatens their preexisting beliefs, said Emory University psychologist Drew Westen, who has conducted brain-scan experiments that show partisans swiftly spot hypocrisy and inconsistencies8212;but only in the opposing candidate. When presented with evidence showing the flaws of their candidate, the same brain regions that Kaplan studied lighted up8212;only this time partisans were unconsciously turning down feelings of aversion and unpleasantness. 8216;8216;The brain was trying to find a solution that would get rid of the distress and absolve the candidate of doing something slimy,8217;8217; Westen said. 8216;8216;They would twirl the emotional kaleidoscope until it gave them a picture that was comfortable.8217;8217; Shankar Vedantam