Abstract
Most cross-modal adaptation studies have a hidden assumption that any cross-modal effects at perceptual levels require concurrent bimodal stimulation. The current study examined temporal rate adaptation to test whether an aftereffect (1) could be induced within vision (V-adaptation/V-test) and audition (AA), (2) would transfer from audition-to-vision (AV), and from vision-to-audition (VA), and (3) would be enhanced in bimodal conditions (AV-AV).
Participants were trained, using feedback, to discriminate the perceived rapidity of repetitive auditory, visual, or audiovisual stimuli presented at a range of randomly ordered frequencies (3.25-4.75 Hz) relative to a learned standard frequency (4 Hz). Afterwards, participants were exposed to 30 adaptation stimuli presented at 3 or 5 Hz, while performing a dummy task of counting gaps in the stimulus trains. The adaptation was either in the same modality/modalities as the training, or across modalities. After the initial training and adaptation phases, adaptation and test trials (which were identical to the training trials, but without feedback) were presented in 20 alternating blocks of 7 trials each.
In all conditions, there was a significant negative aftereffect, such that stimuli were perceived to be slower after exposure to the fast adaptation stimuli, and the reverse. Remarkably, this occurred even in the AV and VA cases, when vision and audition were never presented concurrently. The magnitudes of the aftereffects were not consistent with predictions based on the reliabilities of the signals; although vision was the less reliable modality in time, it did not shift significantly more than audition, and audition did not induce larger shifts than vision. The shift in the AV-AV case was also not predictable based on the within-modal cases.
These findings suggest that sensory information can have perceptual influences beyond the modality in which it is presented. They also place constraints on models of multisensory interactions.
Meeting abstract presented at VSS 2012