Temporal expectation triggers priority shifts in working memory that lead to forgetting.

Working memory (WM) flexibly prioritizes task-relevant information over short intervals, serving as a critical gateway to long-term memory (LTM). However, how this dynamic prioritization influences what is ultimately retained in LTM remains unclear. Here, we investigated the long-term consequences of internally guided prioritization shifts within WM. Human participants (N = 20) encoded two items (a face and a scene) associated with short (1 s) and long (4 s) delays, where the face was probed after 1 s or not at all, and the scene was probed after 4 s only if the face was not tested. Using multivariate pattern analysis (MVPA) of electroencephalography (EEG) data, we tracked fluctuations in neural representations of both memory items as participants redirected internal attention from one to the other across the delay period. Neural dynamics during reprioritization predicted LTM outcomes for the de-prioritized items. Specifically, forgetting was associated with a marked decrease in neural evidence for the deprioritized item, accompanied by a concurrent increase in neural evidence for the newly prioritized item. These findings demonstrate that temporal expectations shape neural dynamics of prioritization in WM that influence retention in LTM.