Abstract
Removing irrelevant information from working memory (WM) can free cognitive resources and reduce interference with current task goals. Beyond these immediate benefits, removal may also support long-term memory processes. We tested this hypothesis using an associative memory paradigm with directed forgetting instructions and characterized the underlying neural mechanisms. In complementary behavioral (N = 22) and fMRI (N = 17) experiments, participants completed an ABC associative memory task using pictures of objects, faces, and scenes. Each A item was sequentially paired with B and C items. Our key manipulation targeted the B items: following B encoding, participants were instructed either to maintain or suppress B. We hypothesized that suppression would impair AB memory but enhance AC memory, and this is precisely what we found. Suppression cues elicited distributed activations across frontoparietal control regions, as expected. Critically, multivoxel pattern analyses revealed enhanced encoding fidelity for C items in hippocampal subregion CA1 following suppression compared to maintenance. During subsequent associative memory tests cued by A items, reactivation of suppressed B items was significantly reduced relative to C items, reflecting diminished competition from B items during retrieval. Together, these findings demonstrate that suppression of unwanted information in WM benefits the formation of new memories by enhancing their encoding fidelity and biasing subsequent memory retrieval away from the suppressed associations.