Testing the response suppression mechanism of working memory

Many working memory (WM) paradigms involve recalling multiple items from the same memory set. Participants rarely repeat items they have already recalled, avoiding repetition errors. To prevent these errors, WM models incorporate a response suppression mechanism that removes recalled items from the set of response options. Despite its importance for our understanding of WM, response suppression has received limited direct testing. To address this gap, we used computational models implementing two hypothetical mechanisms of response suppression to derive predictions and tested these predictions experimentally. Participants were asked to recall the same items multiple times during a single trial. If already recalled items are removed from the response set to prevent repetition errors, memory performance should be impaired when the same item is tested again. Contrary to this, we found that memory performance was unimpaired when the same item was tested a second time, and even displayed a recall advantage. Therefore, this study demonstrates the implausibility of response suppression to account for how people avoid repetition errors. We discuss alternative explanations.