Cognitive control and suppression of memories of an emotional film.

Relatively weak cognitive control existing prior to a stressful event may be associated with intrusive memories of that stressor afterwards. To test this possibility, we tested participants under circumstances that putatively decrease cognitive control and explored how this affected the relation between indices of cognitive control and intrusive memories. Evening type participants (N = 80) were tested at either an optimal or a non-optimal time of day. Tests of working memory capacity and inhibitory control were administered. Subsequently, participants saw an emotional film fragment and engaged in thought suppression afterwards. Results show different correlational patterns in time-of-testing groups. At non-optimal times there were negative, but relatively weak correlations between working memory capacity and intrusions. Better inhibitory control was associated with fewer intrusions during the initial minute of the thought suppression period and with fewer self-reported intrusions. At optimal times however, these correlations were absent. Working memory capacity even showed robust correlations in the opposite direction. These findings cast doubts on the suitability of indices of working memory capacity for testing the idea that relatively weak cognitive control is linked to intrusive memory phenomena. Specific measures of inhibitory control may prove to be more appropriate for testing this idea.