Determining the mechanisms through which recent life stress predicts working memory impairments: precision or capacity?

Prior research has found that recent life stress exposure is related to poorer working memory performance, but it remains unclear which aspects of working memory are related to stress. To address this important issue, we examined the extent to which recent life stress exposure was associated with working memory capacity (i.e., the number of items that can be held in working memory) and working memory precision (i.e., the quality of representations of items held within working memory) in a sample of 260 healthy young adults (Mage = 19.95 years old; range = 18–33). Recent life stress exposure and working memory were assessed with the Stress and Adversity Inventory for Daily Stress (Daily STRAIN) and color wheel task, respectively. We found that recent life stress was selectively associated with lower working memory capacity; moreover, the association of recent life stress with capacity was significantly stronger in magnitude than the non-significant association of recent life stress with precision. These associations were robust while controlling for potential confounds, including demographic factors, negative affect, and cumulative lifetime stress exposure. These results thus suggest that stress-related degradations in working memory capacity may help explain how recent life stress exposure affects working memory performance.