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Monday, October 10, 2011

 Brain imaging reveals why we remain optimistic in the face of reality

People who are very optimistic about the outcome of events tend to learn only from information that reinforces their rose-tinted view of the world, related to a “faulty” function of their frontal lobes, researchers at the Wellcome Trust Centre for Neuroimaging at UCL (University College London) have shown.

This is a problem that has puzzled scientists for decades: why is human optimism is so pervasive, when reality continuously confronts us with information that challenges these biased beliefs? In this new study, the researchers found this due to errors in how we process the information in our brains.

Nineteen volunteers were presented with a series of negative life events, such as car theft or Parkinson’s disease, while lying in a functional magnetic resonance imaging (fMRI) scanner, which measures activity in the brain. They were asked to estimate the probability that this event would happen to them in the future. After a short pause, the volunteers were told the average probability of this event to occur. In total, the participants saw eighty such events.

After the scanning sessions, the participants were asked once again to estimate the probability of each event occurring to them. They were also asked to fill in a questionnaire measuring their level of optimism.

The researchers found that people did, in fact, update their estimates based on the information given, but only if the information was better than expected. For example if they had predicted that their likelihood of suffering from cancer was 40%, but the average likelihood was 30%, they might adjust their estimate to 32%. If the information was worse than expected — for example, if they had estimated 10% — then they tended to adjust their estimate much less, as if ignoring the data.

The results of the brain scans suggested why this might be the case. All participants showed increased activity in the frontal lobes of the brain when the information given was better than expected, this activity actively processed the information to recalculate an estimate.

However, when the information was worse than estimated, the more optimistic a participant was (according to the personality questionnaire), the less efficiently activity in these frontal regions coded for it, suggesting they were disregarding the evidence presented to them.

For example, “many experts believe the financial crisis in 2008 was precipitated by analysts overestimating the performance of their assets even in the face of clear evidence to the contrary,” said researcher Dr. Tali Sharot of UCL.

Read more: http://goo.gl/7QxRC



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