22 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? To answer this question, my colleague, cognitive neuroscientist Sara Bengtsson, devised an experiment in which she manipulated positive and negative expectations of students while their brains were scanned and tested their performance on cognitive tasks. To induce expectations of success, she primed college students with words such as smart, intelligent and clever just before asking them to perform a test. To induce expectations of failure, she primed them with words like stupid and ignorant. The students performed better after being primed with an affirmative message. Examining the brain-imaging data, Bengtsson found that the students' brains responded differently to the mistakes they made depending on whether they were primed with the word clever or the word stupid. When the mistake followed positive words, she observed enhanced activity in the anterior medial part of the prefrontal cortex (a region that is involved in self-reflection and recollection). However, when the participants were primed with the word stupid, there was no heightened activity after a wrong answer. It appears that after being primed with the word stupid, the brain expected to do poorly and did not show signs of surprise or conflict when it made an error. A brain that doesn't expect good results lacks a signal telling it, "Take notice — wrong answer!" These brains will fail to learn from their mistakes and are less likely to improve over time. Expectations become self- fulfilling by altering our performance and actions, which ultimately affects what happens in the future. Often, however, expectations HOUSE_OVERSI