Item-specific congruency effects in nonverbal auditory Stroop.

In the current study, participants judged as 'low' or 'high' either the location or the frequency of a single tone presented in one of two locations at one of two frequencies. The classification associated with the irrelevant feature could be either congruent or incongruent with the required response. The results of Experiment 1 revealed that responses were made more slowly on incongruent than on congruent trials, regardless of whether participants judged sounds according to their location or their pitch. In Experiment 2, we manipulated the probability that the classification associated with the irrelevant acoustic feature was consistent with the classification associated with the task-relevant dimension. In this experiment responses were made more quickly on congruent trials when the response associated with the irrelevant feature was likely to be consistent with the required response, and on incongruent trials when the response associated with the irrelevant feature was likely to be inconsistent with the required response.