Hubner, R. & Grzyb, K. R.
University of Konstanz
It is a well-known phenomenon that response repetitions (RR) produces costs on task-switch trials. However, the size of these costs varies considerable between different experiments. This suggests that several factors contribute to these costs. Unfortunately, up to now these factors are largely unknown. Therefore, the goal of the present study was to examine the extent to which different factors affect the size of RR costs. Specifically, we investigated the role of congruency, i.e. whether the stimuli activate only the correct response or also the incorrect one, and of valence, i.e. whether the stimuli activate only the relevant task or also the irrelevant one. We report a series of experiments in which we show that these conflicting stimulus properties increase RR costs. With simple univalent stimuli RR costs are relatively small but still reliable, which indicates that responses are generally inhibited after their execution. However, by adding incongruent stimulus items or by using bivalent stimuli the small response inhibition effect can be amplified. Moreover, if both factors are combined, then RR costs can increase dramatically. This shows that response conflict and task conflict interact. Possible accounts of this interaction are discussed.