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The capacity to envision the future relies partly on the hippocampus, a brain structure that is crucial to memory. Patients with damage to their hippocampus are unable to recollect the past, but they are also unable to construct detailed images of future scenarios. They appear to be stuck in time. The rest of us constantly move back and forth in time; we might think of a conversation we had with our spouse yesterday and then immediately of our dinner plans for later tonight.
But the brain doesn't travel in time in a random fashion. It tends to engage in specific types of thoughts. We consider how well our kids will do in life, how we will obtain that sought-after job, afford that house on the hill and find perfect love. We imagine our team winning the crucial game, look forward to an enjoyable night on the town or picture a winning streak at the blackjack table. We also worry about losing loved ones, failing at our job or dying in a terrible plane crash but research shows that most of us spend less time mulling over negative outcomes than we do over positive ones. When we do contemplate defeat and heartache, we tend to focus on how these can be avoided.
Findings from a study I conducted a few years ago with prominent neuroscientist Elizabeth Phelps suggest that directing our thoughts of the future toward the positive is a result of our frontal cortex's communicating with subcortical regions deep in our brain. The frontal cortex, a large area behind the forehead, is the most recently evolved part of the brain. It is larger in humans than in other primates and is critical for many complex human functions such as language and goal setting.
Using a functional magnetic resonance imaging (fMRI) scanner, we recorded brain activity in volunteers as they imagined specific events that might occur to them in the future. Some of the events that I asked them to imagine were desirable (a great date or winning a large sum of money), and some were undesirable (losing a wallet, ending a romantic relationship). The volunteers reported that their images of sought-after events were richer and more vivid than those of unwanted events.
This matched the enhanced activity we observed in two critical regions of the brain: the amygdala, a small structure deep in the brain that is central to the processing of emotion, and the rostral anterior cingulate cortex (rACC), an area of the frontal cortex that modulates emotion and motivation. The rACC acts like a traffic conductor, enhancing the flow of positive emotions and associations. The more optimistic a person was, the higher the activity in these regions was while imagining positive future events (relative to negative ones) and the stronger the connectivity between the two structures.
The findings were particularly fascinating because these precise regions the amygdala and the rACC show abnormal activity in depressed individuals. While healthy people expect the future to be slightly better than it ends up being, people with severe depression tend to be pessimistically biased: they expect things to be worse than they end up being. People with mild depression are relatively accurate when predicting future events. They see the world as it is. In other words, in the absence of a neural mechanism that generates unrealistic optimism, it is possible all humans would be mildly depressed.
Can Optimism Change Reality?
The problem with pessimistic expectations, such as those of the clinically depressed, is that they have the power to alter the future; negative expectations shape outcomes in a negative way. How do expectations change reality?