The perception of auditory-tactile integration

Abstract

This project explores the perceptual interactions between certain auditory and tactile stimuli in an objective manner. Our hypothesis states that if the auditory and tactile systems integrate into a common pathway, the d‐prime measure of the two sensory stimuli presented simultaneously will be significantly greater than the d‐prime measure of the individual sensory stimuli. If the stimuli are judged independently, the resulting d‐prime will be close to the root‐squared sum of the individual sensory d‐primes. If the stimuli are integrated into a single percept, the d‐prime will be close to the sum of the individual d‐primes. This experiment presents 250 Hz vibratory stimuli to the fingertip and 250 Hz tones binaurally at the subject’s detection threshold. Experimental measurements of d‐prime were obtained for auditory‐alone, tactile‐alone, and combination of auditory plus tactile. All testing used auditory white noise of 50 dB SPL. Effects of relative tactile‐auditory phase and temporal asynchrony of the stimuli are explored. Preliminary data suggest that under certain conditions the two sensory stimuli integrate in a common pathway to form a single percept, that the stimuli must be synchronous for integration to occur, and that relative tactile‐auditory phase has no effect on integration. [Hertz Foundation, NIH RO1‐DC000126‐25, ROI‐DC000117.]