Response inhibition in the task-switching paradigm

Abstract

In a task-switching paradigm, response repetition (RR) often produces costs in task-switch trials but smaller costs or even benefits in task-repeat trials. Response inhibition accounts consistently attribute negative RR effects to the inhibition of the previous response, but they have different views on this inhibition process. According to the task-specific inhibition hypothesis, the previous response is inhibited when the task-switch is called for; whereas according to the general inhibition hypothesis, the response was generally inhibited after the execution. The present study utilized the electroencephalographs (EEGs) to investigate the response inhibition in the task-switching paradigm, with lateralized upper-alpha and beta enhancements serving as indexes of response inhibition. In blocks with task preparation, a task cue during the response-stimulus interval (RSI) was used to indicate which task was required, and the blocks without task preparation served as the control condition. The result indicated that, during the cue-stimulus interval (CSI), lateralized upper-alpha enhancements appeared only in trials with task-switch preparation, supporting the task-specific inhibition hypothesis. By contrast, regardless of whether there was task preparation and which task to prepare, lateralized beta enhancements appeared during the RSI, which provided evidence for the general inhibition hypothesis. These results suggest the existence of two different response inhibition processes in the task-switching paradigm.