"Leader-follower" dynamic perturbation manipulates multi-item working memory in humans.

Manipulating working memory (WM) is a central yet challenging question. Previous studies posit that WM items with varied memory strengths reactivate at different latencies, supporting a time-based mechanism. Motivated by this view, here we developed a purely bottom-up, "Leader-Follower" behavioral approach to manipulate WM in humans. Specifically, task-irrelevant, flickering color discs that are bound to each of the memorized items are presented during the delay period, and the ongoing luminance sequences of the color discs follow a "Leader-Follower" relationship, i.e., hundreds-of-millisecond temporal lag. We show that this dynamic behavioral approach leads to better memory performance for the item associated with the temporally advanced luminance sequence ("Leader") than that with the temporally lagged luminance sequence ("Follower"), yet with limited effectiveness. Taken together, our findings constitute evidence for the essential role of temporal dynamics in WM operation and offer a promising, non-invasive WM manipulation approach. Significance Statement Working memory (WM) is known to be the "sketchpad of conscious thought'' that allows us to temporally hold and manipulate limited amounts of information to guide future behavior. A major challenge in the WM field concerns how multiple items could be simultaneously retained while not be confused with each other. Previous work advocates a time-based mechanism, with the item with stronger strength firing at earlier latency than that with weaker memory. Motivated by the time-based view, here we developed a novel behavioral approach, namely the "Leader-follower" dynamic perturbation, to alter WM performance in humans. Our findings constitute new evidence for a time-based WM mechanism and offers a brand-new behavioral approach to directly manipulate WM, but with the need for replication.