Just don't think about it. Trying to stop smoking? Avoid eating sweets? Get over a relationship? Stop thinking about it. This is surprisingly bad advice. Suppressing thoughts may actually be counter-productive.
Don't think about white bears. While reading the rest of this blog post, do not think about white bears. Daniel Wegner and his colleagues have frequently investigated the effects of asking people to not think about white bears (and other things). They've made two primary findings. First, people experience difficulty suppressing thoughts. Trying to suppress is not 100% effective - that white bear continues to inhabit your thoughts instead of the polar icecap. When suppressing, most people keep other thoughts in mind and keep in mind the idea that they are not thinking about something. Every now and then you think about what you are not thinking about just to make sure you are not thinking about it and there it is: The white bear, or chocolate bars, or cigarettes, or that old flame.
The second, and more important finding, is that people experience a rebound effect after trying to suppress a thought - they think about the white bear more following suppression attempts. Compared to people encouraged to simply think about the bear, people who first tried to suppress thoughts of the white bear have many more occurrences of the white bear thought. Wegner and his colleagues wrote that "the paradoxical effect of thought suppression is that it produces a preoccupation with the suppressed thought."
Wegner has often suggested that rebounds following thought suppression may contribute to obsessions, dieting failures, and difficulties stopping behaviors like smoking. In new research published this year, James Erskine and his colleagues have experimentally shown that thought suppression has counter-productive effects on behaviors.
Erskine and Georgiou conducted an experiment in which they looked at the effects of suppressing thoughts of chocolate (something with which I have some personal experience). First, participants engaged in a task of recording their thoughts. One-third were asked to think about chocolate, one-third to suppress thoughts of chocolate, and one-third to simply record their thoughts with no suggestions about content. Later all participants were asked to rate some chocolate on several qualities related to taste. The issue was not their ratings, but rather how much chocolate they ate. People who had tried to suppress thoughts about chocolate ate more chocolate! Suppression not only led to a rebound in chocolate thoughts, but also to a rebound in eating chocolate. Trying to not think about that candy bar may make consumption of that candy bar (and its friends in the vending machine) even more likely. The effect was most noticeable in restrained eaters - that is, people already trying to limit food intake.
In a related study, Erskine, Georgiou, and Kvavilashvili tried thought suppression with smokers. In this case, they undertook a much more extensive study. Smokers recorded the number of cigarettes they smoked for three weeks (they also recorded lots of other information such as stress, smoking attitudes, etc.). The first week served as the baseline for cigarette consumption. In week 2, some smokers attempted to suppress thoughts of smoking, some were encouraged to think about smoking as frequently as they could, and a control group simply continued to record cigarette consumption. The good news? Suppressions led to a decrease in smoking during the week when the smokers were suppressing thoughts of smoking. The bad news? A major rebound effect occurred. In the next week, those who had previously tried to suppress thoughts of smoking smoked more cigarettes. When they stopped suppressing, they increased smoking.
Don't think about it is bad advice. Although people can have limited success suppressing thoughts for a while, the thought will rebound. The cool finding in Erskine and colleagues' research is that rebounding thoughts led to rebounding behaviors - more chocolate consumed and cigarettes smoked. Perhaps we should suppress thoughts about suppression.