A neural network that may generate the human tendency to be optimistic has been identified by researchers at New York University. As humans, we expect to live longer and be more successful than average, and we underestimate our likelihood of getting a divorce or having cancer. The results, reported in the most recent issue of Nature, link the optimism bias to the same brain regions that show irregularities in depression.
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The study was conducted by a team of researchers from the laboratory of NYU Professor Elizabeth Phelps. The lead author is Tali Sharot, now a post-doctoral fellow at University College London.
The NYU researchers used functional magnetic resonance imaging (fMRI) to examine brain function while participants thought of possible future life events (such as winning an award or the end of a romantic relationship).
When participants imagined positive future events relative to negative ones, enhanced activation was detected in the rostral anterior cingulate and amygdala, which are the same brain areas that seem to malfunction in depression, said Sharot. Activation of the rostral anterior cingulate was correlated with trait optimism, with more optimistic participants showing greater activity in this region when imagining future positive events.
The team found that participants were more likely to expect positive events to happen closer in the future than negative events, and to imagine them with greater vividness.
Our behavioral results suggest that while the past is constrained, the future is open to interpretation, allowing people to distance themselves from possible negative events and move closer toward positive ones, said Phelps, a professor of psychology and neural science. Understanding optimism is critical as optimism has been related to physical and mental health. On the other hand, a pessimistic view is correlated with severity of depression symptoms.
The brain imaging findings offer a possible mechanism mediating the behaviorally observed optimism bias. The rostral anterior cingulate has previously been shown to be involved in the regulation of emotional responses. The current results suggest that in healthy individuals this region may help integrate and regulate emotional and autobiographical information to generate a positive view of the future.
The research was supported by the National Institutes for Mental Health, the Seaver Foundation, and a Margaret and Herman Sokol Postdoctoral Fellowship.