Rumination Decreases Cognitive Efficiency in a Working Memory Task

Depression is a sustained negative mood state characterized by working memory (WM) and attentional impairments (Etkin, 2013). One aspect of depression is rumination, which is the repetitive thinking of one’s negative mood. Frequent rumination is theorized to be associated with WM dysfunction, therefore we hypothesized that rumination would be a moderator for WM performance in our task. Participants completed rumination and depression questionnaires prior to partaking in an EEG recorded WM task. In the task, to-be-remembered items were presented individually, and after a short delay, a match or nomatch probe was displayed. Participants were then instructed to respond to the probe by recalling the location of each item. Effective performance was assessed by the number of correct trials. Results provide support for the hypothesis. Rumination was found to impact neural activity observed during the delay period: high ruminators displayed greater amplitudes across conditions compared to low ruminating counterparts. Rumination was not found to effect accuracy. Thus, high ruminators require more effort than lower ruminators to achieve the same accurate performance level, indicating efficiency but not effective performance being impacted. Further, results suggest depression as a whole cannot solely provide information on the cognitive deficits associated with this disorder; however, by separating the underlying mechanisms, a greater insight into understanding these deficits can be gained