In January 2006, Drew Westen and a team from Emory University announced at the annual Society for Personality and Social Psychology conference in Palm Springs, California the results of a study showing the brain activity for confirmation bias. Their results suggest the unconscious and emotion driven nature of this form of bias.
The study was carried out during the pre-electoral period of the 2004 presidential election on 30 men, half who described themselves as strong Republicans and half as strong Democrats. During a functional magnetic resonance imaging (fMRI) scan the subjects were asked to assess contradictory statements by both George W. Bush and John Kerry. The scans showed that the part of the brain associated with reasoning, the dorsolateral prefrontal cortex, was not involved when assessing the statements. Conversely, the most active regions of the brain were those involved in processing emotions (orbitofrontal cortex), conflict resolution (anterior cingulate cortex) and making judgment about moral accountability (posterior cingulate cortex). [1]
Dr. Westen summarised the work: [2]
None of the circuits involved in conscious reasoning were particularly engaged. Essentially, it appears as if partisans twirl the cognitive kaleidoscope until they get the conclusions they want, and then they get massively reinforced for it, with the elimination of negative emotional states and activation of positive ones... Everyone from executives and judges to scientists and politicians may reason to emotionally biased judgments when they have a vested interest in how to interpret 'the facts'.
this is probably why most people stick to one party or the other through everything.
