In a study by Wegner et al., participants were instructed to not think of white bears for a period of 5 minutes and to ring a bell each time the thought of a white bear crossed their minds. Following this initial suppression period, another 5-minute phase was introduced during which participants could think of anything they wanted, including white bears, and continued to ring a bell each time the thought of a white bear surfaced. This group was compared to another group of participants who performed the expression phase first, without initial suppression. The results showed that suppression in the first phase was difficult for the participants—most of them thought of white bears despite instructions not to think of them—and that thoughts of white bears rebounded after suppression in the second, free expression phase. In other words, the rate of white bear thoughts during the expression phase was higher in the suppression-first group than in the expression-first group.
In order to control thoughts and behaviours, people often try to suppress unwanted thoughts. Dieters may try to avoid thinking about fatty foods, a person in drug rehabilitation may try not to think of drugs, a student may attempt to concentrate on an exam and suppress thoughts of distracting objects, and a professor may try to suppress aggressive thoughts about a colleague he finds immoral and socially unacceptable. Yet, many times these attempts to suppress one’s thoughts not only fail but also produce the opposite effect.
Source: This is an excerpt adapted from “A motivational model of post-suppressional rebound,” published in European Review of Social Psychology, by Jens Förster and Nira Liberman