Dysphoria, Depressive Rumination, and Working Memory

Abstract

Current research on depression and rumination has produced mixed and sometimes incongruent results. Some researchers have found evidence of general cognitive deficits, while others have found evidence of only mood-congruent cognitive deficits. Recent research on deficits in working memory (WM) has indicated that general WM deficits occurred in a reading span task after people suffering from depression were exposed to mood congruent stimuli in a modified reading span task (affective transfer, Hubbard et al. 2016). However, the precise nature of these WM deficits remains unclear. The present study examined these effects with the decomposition of a modified n-back task into its component parts: WM updating and focus switching. Whether depression, depressive rumination, and mood were predictive of updating and focus switching was assessed. This study employed 52 participants split into two groups: a control group who completed only non-emotional tasks over two sessions, and an experimental group, who completed first a set of emotional tasks, followed by a set of non-emotional tasks. In this way, performance in the set 2 tasks was compared based on whether the participants were in the emotional or non-emotional group in set 1. This, effectively, is an extension of the affective transfer effect of Hubbard et al. (2016) to see if updating costs or switch costs or both are the driving cause of affective transfer. Furthermore, this study examined whether there were general or mood congruent WM deficits in the emotional set 1 task for these updating and focus switch costs. Affective transfer should have occurred in at least one of WM updating or focus switching, for individuals with elevated depressive symptoms, especially those who concurrently tended to engage in depressive rumination. It did not. Furthermore, elevated depression and depressive rumination were not predictive of general nor of mood-congruent deficits in WM updating or focus switching.