Emory study reveals the political brain

The researchers wanted to discover why Democrats and Republicans can hear the same information, but reach opposite conclusions.

The investigators used functional magnetic resonance imaging, or fMRI, to study a sample of committed Democrats and Republicans immediately prior to the 2004 U.S. presidential election.

The participants were asked to evaluate threatening information about their own candidate while undergoing fMRI. The scientists say what they found was striking.

"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 who led the study. "What we saw instead was a network of emotion circuits lighting up.

Once partisans reached completely biased conclusions -- essentially ignoring information that couldn't be rationally discounted -- they then got a blast of activation in circuits involved in reward.

"None of the circuits involved in conscious reasoning were particularly engaged," he said.

The findings are to be presented during this week's annual meeting of the Society for Personality and Social Psychology in Palm Springs, Calif.

Copyright 2006 by United Press International