The Prioritization of Stressful Episodes in Working Memory

Acute stress is known to enhance long-term memory for central details of a stressful episode. However, whether this prioritization occurs within the brief timescale of working memory (WM) remains unknown. The present study investigated the prioritization of stressful episodes in WM across two distinct neuroendocrine phases of the stress response.

Two experiments were conducted using a modified Maastricht Acute Stress Test (MAST) to induce stressful episodes and to establish associated central (COs) and peripheral (POs) objects. Experiment 1 assessed WM immediately post-stress (non-genomic phase; N = 57). Experiment 2 assessed WM one hour post-stress (genomic phase; N = 61) with a sequential presentation design to reduce encoding competition. Both experiments included non-stressful control (friendly MAST, f-MAST) groups.

In both experiments, the MAST group responded significantly faster to COs than to both POs and neutral objects in the WM task, whereas the f-MAST group showed no such differences. Critically, this prioritization was robust across both the immediate non-genomic phase and the delayed genomic phase, and persisted even under sequential presentation.

Stressful episodes are robustly prioritized in WM. This prioritization effect remains stable across both the immediate and delayed cortisol phases, and persists even when encoding competition is minimized through sequential presentation. These findings suggest that the prioritization involves not only initial attentional capture but also biased maintenance in WM. This may reflect a durable cognitive bias established rapidly during acute stress.