Visual working memory resource allocation is affected by stimulus-related and individuals' state- and trait-related factors

Abstract

Visual working memory (VWM) is a system to actively maintain visual information to meet the needs of ongoing cognitive tasks. There is a trade-off between the precision of each representation stored in VWM and the number of representations due to the VWM resource limit. VWM resource allocation can be studied in two ways: one way is to investigate the ability to voluntarily trade off VWM precision and representation number stored in VWM; the other way is to investigate the ability to filter task-irrelevant information. The factors that influence these two aspects remain unclear. I investigated the influence of stimulus presentation time, VWM capacity, and emotional state on this trade-off ability attributed to VWM (Study I and Study II). In addition, I investigated the influence of facial expression of distractor stimuli, VWM capacity, and depressive symptoms on filtering ability (Study III and Study IV). Study I demonstrated that there is a positive relationship between VWM capacity and voluntary trade-off ability only when stimulus presentation time is long. Study II found that participants can improve VWM precision in a negative emotional state by reducing the number of representations stored in VWM when the stimulus presentation time is long. Study III found that face distractors could be filtered by participants with high VWM capacity, while low capacity participants had difficulties in filtering both angry and neutral face distractors. Study IV found that dysphoric participants could filter both sad and fearful face distractors. In contrast, non-dysphoric participants failed to filter fearful face distractors, but they could filter sad face distractors efficiently. Overall, the results of these studies suggest that VWM resource allocation is affected by stimulus-related and individuals' state- and trait-related factors (i.e., stimulus presentation time, VWM capacity, emotional state, facial expression, and depressive symptoms). These findings provide a better understanding of VWM resource allocation, which can possibly be applied in the future when developing methods for cognitive training and clinical purposes.