Processing in working memory boosts long-term memory representations and their retrieval

Prior research has explored how working memory influences the formation of new long-term memories, but its role in modifying existing representations remains unclear. This study examines whether attentional prioritization and testing in working memory enhance long-term memory retrieval and investigates the underlying neural mechanisms. Eighty-six participants completed a three-phase memory task combining a long-term memory- with a working memory retro-cue paradigm. First, participants learned object-location associations. Next, during a working memory task, some objects have undergone attentional prioritization and testing, others have only been tested in working memory. Finally, participants retrieved the object locations from long-term memory. Three key findings emerged: (1) both attentional prioritization and testing in working memory improved long-term memory retrieval; (2) serving as a probe in working memory further contributed to long-term memory enhancement, with benefits observed at behavioral and neural levels; and (3) cross-phase decoding revealed a comparable representational format for location information across task phases, possibly explained by the neural reinstatement of location information across phases. These results suggest that working memory dynamically shapes long-term memory representations, playing a more active and integrated role in long-term memory formation than previously thought.