The Atlantic interviews Julie Norem, a psychology professor at Wellesley College and author of The Positive Power Of Negative Thinking:
Olga Khazan: What is defensive pessimism?
Julie Norem: It’s a strategy for dealing with anxiety and helping to manage anxiety so that it doesn’t negatively influence performance. If you feel anxious in a situation, it doesn’t really matter if it’s realistic or not, you feel how you feel. It’s hard not to feel that particular way. If you feel anxious, you need to do something about it. Usually people try to run away from whatever situation makes you anxious. But there are other ways of dealing with it. Defensive pessimism is one way.
When people are being defensively pessimistic, they set low expectations, but then they take the next step which is to think through in concrete and vivid ways what exactly might go wrong. What we’ve seen in the research is if they do this in a specific, vivid way, it helps them plan to avoid the disaster. They end up performing better than if they didn’t use the strategy. It helps them direct their anxiety toward productive activity.
See also: The Powerlessness of Positive Thinking