Working memory capacity and suppression of intrusive thoughts

We sought to show that individual differences in working memory capacity are related to the ability to intentionally suppress personally relevant intrusive thoughts, and that this effect cannot be explained by differences in negative mood. Sixty participants identified their most frequent intrusive thought and then completed a thought suppression task. Better performance on a measure of working memory capacity (OSPAN) was related to having fewer intrusions in the suppression condition but was unrelated to number of intrusions in the expression condition, suggesting a specific association with attempts to inhibit unwanted thoughts. In contrast, a more negative mood was related to having more intrusions in both conditions, suggestive of a more general influence on the accessibility of unwanted thoughts. Working memory capacity was not associated with negative mood or with the frequency of intrusive thoughts reported in everyday life. The findings extend previous results to the domain of personally relevant intrusive thoughts and support the idea that individual differences in the cognitive abilities supporting inhibitory mechanisms are relevant to clinical conditions such as obsessive-compulsive disorder and posttraumatic stress disorder. (C) 2004 Elsevier Ltd. All rights reserved.