Grzyb, K. R. & Hubner, R.
University of Konstanz, Germany
Under task switching response repetitions (RR) are typically associated with costs compared to response shifts. Moreover, when the stimulus on the previous trial was congruent RR costs are usually larger than when it was incongruent. This previous-trial congruency effect has been explained by assuming that a response is generally inhibited after its execution and that the amount of inhibition depends on the activation of the response on the previous trial. Here, we investigated which property of the response activation on the previous trial is crucial in determining the amount of inhibition: the absolute activation of the correct response or the activation difference between the alternative responses. To differentiate between these two possibilities we compared RR costs after congruent, neutral, and incongruent trials. In two experiments we found similar RR costs after congruent and neutral trials, whereas the RR costs were smaller after incongruent trials. These results support the hypothesis that the amount of response inhibition is determined by the activation differences between the response alternatives on the previous trial.