Tactile facilitation of auditory stimulus detection
Poster Presentation

Helge Gillmeister
School of Psychology, Birkbeck College, University of London

Martin Eimer
School of Psychology, Birkbeck College, University of London

     Abstract ID Number: 82
     Full text: Not available
     Last modified: March 20, 2005

Abstract
Our previous investigations have shown that simultaneous irrelevant touches enhance the perceived loudness of tones. In line with a multisensory interpretation, this enhancement was contingent on the simultaneity of auditory and tactile stimuli, was systematically modified by their relative intensities, and had direct and early physiological correlates, evident in the event-related potentials to the sounds. However, the method of comparing behaviour in unimodal situations with that in bimodal situations does not exclude the possibility that processes other than multisensory integration were measured in these studies. Here we used a criterion-free forced-choice task to show that the mechanisms underlying the contribution of touch to the perception of loudness can improve people’s ability to detect sounds. Observers had to indicate in which of two adjacent temporal intervals a tone was present. Tones could have one of three near-threshold intensities. Both intervals contained a tactile stimulus, which could occur at varying stimulus-onset asynchronies with respect to the tone, if present. Results showed that the detection of tones was facilitated by simultaneous touches, compared to touches occurring earlier or later in the interval. These findings demonstrate that the tactile contribution to the perception of loudness is a genuine multisensory phenomenon.