Response Inhibition Modulates Response Conflict in Task Switching

Although response repetition (RR) effects vary considerably between conditions and studies, little is known about the causes. Recently, RR costs on task switch trials have been found to be larger for incongruent stimuli that activate both alternative responses than for neutral ones. Here, we investigated if this modulation can be explained by an amplification of response conflict account (ARC). It assumes that a response shift bias that is responsible for the basic RR costs amplifies the response conflict induced by incongruent stimuli specifically on trials where the response repeats. Consequently, RR costs are increased for incongruent stimuli. Because supporting evidence for this account was restricted to task shift trials, we tested if the ARC account holds also more generally, that is, on task repetition trials. To this end, we applied a rather common alternating runs paradigm and presented neutral and incongruent stimuli. Results show that the congruency effect was larger on RR trials than on RS trials. Because this relation was independent of task transition, it is consistent with the idea that, in order to promote behavioral flexibility in task switching contexts, a general response shift bias is induced by inhibiting the previous response.