Coactive processing of dimensionally redundant targets within the auditory modality?

Previous reaction time studies have demonstrated coactivation processes within the visual modality for redundant stimuli that differ in two dimensions (e.g., shape and color). The present study provides novel results of analogous processes within the auditory modality. A redundant-target effect (RTE) was obtained in a Go/NoGo experiment using tones that differed in location and/or frequency. Participants were asked to respond to a specific tone location (e.g., left) and/or tone frequency (e.g., 200 Hz) of auditory stimuli. For redundant targets (e.g., a 200 Hz tone presented to the left), an RTE was observed which was too large to be explained by mere statistical facilitation. Therefore, responses to redundant targets were triggered by a combined activation of the target dimensions. The results are consistent with the modular hybrid account of Mordkoff and Yantis (1993).