Individual Differences in Multisensory Interactions:The Influence of Temporal Phase Coherence and Auditory Salience on Visual Contrast Sensitivity.

Hiu Mei Chow,Vivian M Ciaramitaro,Xenia Leviyah

doi:10.3390/vision4010012

Abstract

While previous research has investigated key factors contributing to multisensory integration in isolation, relatively little is known regarding how these factors interact, especially when considering the enhancement of visual contrast sensitivity by a task-irrelevant sound. Here we explored how auditory stimulus properties, namely salience and temporal phase coherence in relation to the visual target, jointly affect the extent to which a sound can enhance visual contrast sensitivity. Visual contrast sensitivity was measured by a psychophysical task, where human adult participants reported the location of a visual Gabor pattern presented at various contrast levels. We expected the most enhanced contrast sensitivity, the lowest contrast threshold, when the visual stimulus was accompanied by a task-irrelevant sound, weak in auditory salience, modulated in-phase with the visual stimulus (strong temporal phase coherence). Our expectations were confirmed, but only if we accounted for individual differences in optimal auditory salience level to induce maximal multisensory enhancement effects. Our findings highlight the importance of interactions between temporal phase coherence and stimulus effectiveness in determining the strength of multisensory enhancement of visual contrast as well as highlighting the importance of accounting for individual differences.

Highlights

We live in a multisensory world where we constantly receive information across our different senses
This study aimed to explore the interaction between temporal coincidence and stimulus This study aimed to explore the interaction between temporal coincidence and stimulus effectiveness, or salience, on multisensory enhancement of the visual contrast of a Gabor pattern effectiveness, or salience, on multisensory enhancement of the visual contrast of a Gabor pattern by by a task-irrelevant sound
Our results provide direct evidence supporting the interaction of temporal coincidence and stimulus effectiveness in determining the strength of multisensory enhancement of visual contrast and stimulus effectiveness in determining the strength of multisensory enhancement of visual contrast highlight the importance of individual differences

Summary

Introduction

We live in a multisensory world where we constantly receive information across our different senses. Participants perceive the same visual stimulus brighter [1,2], better (i.e., lower detection threshold or higher sensitivity [3,4,5]) and faster [6], when it is accompanied by a sound versus without a sound, despite the sound bearing no useful task-relevant information. Such effects are important since the enhancement of low-level features (such as brightness or contrast) can potentially enhance the representation of mid-level features, such as object contour and shape completion [7]. An examination of factors contributing to multisensory enhancement provides critical knowledge for understanding basic mechanisms of multisensory processing, as well as its application in areas such as sensory rehabilitation.

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