Eren Günseli¹; ¹Sabanci University, Istanbul

What determines when long-term memory (LTM) is reactivated into working memory (WM)? Across three EEG experiments, we examined how WM–LTM dynamics respond to different forms of contextual structure. Experiment 1 involved long runs of trials with one task rule, followed by a switch to a different stable rule (e.g., A–A–A–A–A–B–B–B–B–B). The same task-relevant memory color repeated across the entire block, including across the rule change. CDA reduced with color repetitions but increased at task rule transitions, reflecting reactivation of the task-relevant color. In Experiments 2–3, memory colors and contextual features (task rule or background color) were manipulated in a 2×2 blocked design: in each block, they either repeated across trials or varied from trial to trial. CDA was reduced in color repetition blocks, consistent with a shift from WM to LTM. Critically, even when contextual features varied from trial to trial, CDA remained low—indicating no reactivation. Together, these findings show that WM is re-engaged when stability breaks and that the brain interprets consistent variability as a stable context. WM reactivation thus reflects the detection of contextual transitions.