Distinct states in visual working memory support memory benefits from extending encoding time

Visual working memory (VWM) is a fundamental cognitive mechanism with limited capacity. Recent research has highlighted the effectiveness of extending the encoding items to enhance VWM capacity. However, the mechanisms responsible for such enhancement remain unclear. Our hypothesis is that the presence of distinct states within VWM (active vs. passive) may contribute to this enhancement. Extending the encoding time allows items that surpass the active storage capacity to temporally transition into the passive state, thus freeing up resources for active storage. To test this, participants were asked to memorize two arrays sequentially, with the first array held in the passive state while they actively maintained the second. We systematically extended the encoding time for the second (active) array and observed memory benefits. These benefits came at the expense of the storage of the first (passive) array, suggesting that items exceeding the active memory capacity are temporarily stored in the passive state. Overall, the presence of distinct states in VWM allows for storing more items. The employment of the passive state contributes to the benefits of extended-encoding time in VWM.