Rebound Effects of Thought Suppression: Instruction-Dependent?

Abstract

Previous studies have shown that when normal subjects are instructed to think of a white bear (“forced” expression instructions), they do so more frequently when they have previously suppressed the thought of a white bear than when they have not suppressed this thought. It has been proposed that this rebound effect of thought suppression provides a laboratory model for the development of real-life obsessions. The present studies were undertaken in order to explore further the tenability of this model. Rebound effects were evaluated when more “liberal” expression instructions (“you might think of a white bear, but you don't have to”) were used. In Experiment 1, no evidence was obtained to suggest that suppression results in a heightened frequency and/or accelerated rate of white bear thoughts during a subsequent expression period (with “liberal” instructions). Interestingly, initial suppression lead to an immediate and stable increase of thought related electrodermal fluctuations. In Experiment 2, it was found that successful suppressors (few target thoughts during suppression) report fewer white bear thoughts during expression (with “liberal” instructions) than unsuccessful suppressors (many target thoughts during suppression). Assuming that the ecological validity of “liberal” expression instructions is greater than that of “forced” instructions, the present findings cast doubt on the claim that the rebound effect mimics the etiology of obsessions. The findings also suggest that it may be the immediate counter-productive effects of suppression that are relevant to theories concerned with obsessions.