Experimental investigation of the interplay between ruminative thinking and working memory capacity: Accounting for affect, modality and metacognition

Limited cognitive resource theories predict that ruminative thinking will lead to a diminished working memory capacity. While some empirical studies have found proof for the negative effect of rumination on working memory capacity, others have not. Moreover, the arousal-enhancement hypothesis predicts that affective state can enhance memory in the context of high arousal. This study aimed to experimentally induce anger and sadness state-related types of rumination and test their general and specific effects on working memory capacity while considering a set of key moderators: (1) affect, (2) modality, and (3) metacognition. The sample consisted of 65 individuals (average age = 27 years, range 18 – 50) who were randomly allocated to three experimental groups (sad rumination, angry rumination and controls). All participants completed a set of self-reports, experimental induction of rumination (or a control procedure) and two change detection working memory tasks with visual/abstract and nameable shapes. We found a significant positive effect of state rumination on working memory capacity (p<.033). There were no differences between sad and angry rumination groups. We found that the verbal processing task with nameable shapes resulted in higher k estimates than the visual processing with abstract shapes (p<.0000001). Modality, affect (incl. depression) and metacognition did not modulate the effect of rumination on WM capacity. A secondary Bayesian analysis confirmed these results. This study is the first to experimentally test the effects of sad and angry state rumination on working memory capacity estimates. The positive effect of state rumination on k favors the arousal induced enhancement of WM hypothesis.