Is There Audio-Tactile Interaction in Perceptual Organization?

Sounds often accompany tactile stimulation. The present study investigated if the temporal coherent auditory and tactile stimuli can be grouped together to form a perceptual stream. The experiments measured listeners' sensitivity to detect synchrony between a pair of auditory or tactile stimuli (in a 2I-2AFC task), either in isolation or embedded in a sequence of stimuli in the same modality (ie, ‘captors’) that was designed to perceptually ‘capture’ the target stimulus into a sequential stream. In some conditions, the captors were presented together with stimuli from the same or different modality. Results show that these accompanying tones did improve auditory synchrony detection when the captors were presented, but the accompanying taps did not, no matter whether the test tone pairs were separated by 6 or 11 semitones. On the other hand, the accompanying tones did not improve tactile synchrony detection when the captors were presented, no matter whether the test tap pairs were on the same hand or different hands. The observations did not find significant audio-tactile interactions in streaming at or below the level of synchrony detection across auditory filters and across hands. Nevertheless, the interactions may occur at higher-level processing of perceptual organization