From Nature:
People have a propensity to be optimistic, expecting to live longer and be healthier than the population average. Elizabeth Phelps and her colleagues from New York University ran into this so-called ‘optimism bias’ when they set out to investigate what happens when people imagine emotional events in the past and future. They had volunteers think about events such as winning an award, or the end of a romantic relationship, and at the same time they scanned their brains using functional magnetic resonance imaging. But the researchers hit on a problem. The volunteers were not good at imagining bad things happening to them. They would even turn relatively neutral events, such as getting a haircut, into positive things. So the team changed their focus: they decided to look at the brain areas involved in the optimism bias instead. The group asked people to imagine positive and negative events that had either happened in the past or might happen in the future. Then, the volunteers rated their levels of optimism (as a general personality trait) using a standard psychological test.
Imagining positive events in the future was accompanied by activity in two areas of the brain that usually regulate how emotion affects memory and decisions: the amygdala, buried deep within the brain, and the front portion of the anterior cingulate cortex (ACC), which sits just behind the eyes. Conversely, activation in both these areas dropped below average when the volunteers thought about future negative events. The more optimistic people considered themselves to be, the greater the activity in the ACC.
More here.
