Refreshing and removing items in working memory: Different approaches to equivalent processes?

Researchers have investigated “refreshing” of items in working memory (WM) as a means of preserving them, while concurrently, other studies have examined “removal” of items from WM that are irrelevant. However, it is unclear whether refreshing and removal in WM truly represent different processes, or if participants, in an effort to avoid the to-be-removed items, simply refresh alternative items. We conducted two experiments to test whether these putative processes can be distinguished from one another. Participants were presented with sets of three words and then cued to either refresh one item or remove two items from WM, followed by a lexical decision probe containing either one of the just-seen words or a non-word. In Experiment 1, all probes were valid and in Experiment 2, probes were occasionally invalid (the probed word was one of the removed/non-refreshed items). In both experiments, participants also received a subsequent surprise long-term memory test. Results from both experiments suggested the expected advantages for refreshed (or non-removed) items in both short-term response time and long-term recognition, but no differences between refresh and remove instructions that would suggest a fundamental difference in processes. Thus, we argue that a functional distinction between refreshing and removal may not be necessary and propose that both of these putative processes could potentially be subsumed under an overarching conceptual perspective based on the flexible reallocation of mental or reflective attention.