When variability becomes stability: Consistent change suppresses memory reactivation

Adaptive cognition requires determining when previously stored information must be re-engaged to guide behavior. Prevailing accounts of working memory and cognitive control propose that contextual change cues the retrieval or reactivation of relevant information, reinstating stored representations into working memory when the task model changes. Here, I show that reactivation depends not on change per se, but on the stability of the change. In an EEG experiment, participants performed visual memory tasks using repeatedly presented items. The task rule was either repeating or consistently varying across trials. While contralateral delay activity (CDA) declined with memory repetition, reflecting reduced working memory engagement, this reduction was unaffected by whether the task rule consistently changed or repeated. Thus, when variability itself was consistent, it was learned as a stable context, no longer prompting reactivation. Reactivation, therefore, is not triggered by change itself but by the failure of contextual stability, revealing that consistent variability is learned as a stable context.