Crossmodal Effects in Task Switching: Modality Compatibility with Vocal and Pedal Responses.

Modality compatibility refers to the similarity between the stimulus modality and the modality of response-related sensory consequences (e.g., vocal output produces audible effects). While previous studies found higher costs of task switching with stimulus-response modality-incompatible tasks (auditory-manual and visual-vocal), the present study was aimed to explore the generality of modality compatibility by examining a new response modality (pedal responses). Experiment 1 showed that the effect of modality compatibility generalizes to pedal responses when these replaced manual responses used in previous studies (i.e., higher switch costs when switching between auditory-pedal and visual-vocal tasks compared to switching between auditory-vocal and visual-pedal tasks). However, in single-task conditions there was no influence of modality compatibility. Experiment 2 was designed to examine whether modality compatibility depends on the frequency of task switches. To this end, one task occurred very frequently, overall decreasing the task switching frequency. Importantly, the results showed a robust task-switching benefit of modality-compatible mappings even for a highly frequent task, suggesting that the sustained representation of potentially competing response modalities affects task-switching performance independent from the actual frequency of the tasks. Together, the data suggest that modality compatibility is an emergent phenomenon arising in task-switching situations based on the necessity to maintain but at the same time separate competing modality mappings, which are characterized by ideomotor ''backward'' linkages between anticipated response effects and the stimuli that called for this response in the first place.