Dolan and Colleagues have done yet another fascinating piece of work, showing brain activity that correlates with the tendency of people to remain overly optimistic even when faced with information about a gloomy future (optimism bias). This is another example of 'not attending to bad news' (noted in a mindblog post last week as underlying some people having less ability to learn from their mistakes). The Sharot et al. study shows that people are selectively worse at incorporating information about a worse-than-expected future, and describes the learning signals in the brain that correlate with this bias:
Unrealistic optimism is a pervasive human trait that influences domains ranging from personal relationships to politics and finance. How people maintain unrealistic optimism, despite frequently encountering information that challenges those biased beliefs, is unknown. We examined this question and found a marked asymmetry in belief updating. Participants updated their beliefs more in response to information that was better than expected than to information that was worse. This selectivity was mediated by a relative failure to code for errors that should reduce optimism. Distinct regions of the prefrontal cortex tracked estimation errors when those called for positive update, both in individuals who scored high and low on trait optimism. However, highly optimistic individuals exhibited reduced tracking of estimation errors that called for negative update in right inferior prefrontal gyrus. These findings indicate that optimism is tied to a selective update failure and diminished neural coding of undesirable information regarding the future.