Stimulus-response bindings contribute to item switch costs in working memory

In counter updating tasks, responses are typically faster when items repeat than when they change (item switch costs). The present study explored the contribution of stimulus-response bindings to these item switch costs. In two experiments, we orthogonally manipulated the repetition/switch of to-be-counted items and the repetition/switch of required manual responses. Item switch costs were considerably lower when item switches were accompanied by response switches than when accompanied by response repetitions. Experiment 2 showed that, although there was also a smaller contribution from stimulus-stimulus bindings (i.e., shape-location), the major part was due to stimulus-response bindings. These results show that in the widely used standard version of the counter updating task, a considerable portion of item switch costs is caused by the unbinding of stimulus-response bindings rather than by processes of switching items in working memory.