Attention to sound improves auditory reliability in audio-tactile spatial optimal integration

The role of attention on multisensory processing is still poorly understood. In particular, it is unclear whether directing attention toward a sensory cue dynamically reweights cue reliability during integration of multiple sensory signals. In this study, we investigated the impact of attention in combining audio-tactile signals in an optimal fashion. We used the Maximum Likelihood Estimation (MLE) model to predict audio-tactile spatial localization on the body surface. We developed a new audio-tactile device composed by several small units, each one consisting of a speaker and a tactile vibrator independently controllable by external software. We tested subjects in an attentional and a non-attentional condition. In the attention experiment participants performed a dual task paradigm: they were required to evaluate the duration of a sound while performing an audio-tactile spatial task. Three unisensory or multisensory stimuli (conflictual or not conflictual sounds and vibrations) arranged along the horizontal axis were presented sequentially. In the primary task subjects had to evaluate the position of the second stimulus (the probe) with respect to the others (in a space bisection task). In the secondary task they had to report occasionally changes in duration of the second auditory stimulus. In the non-attentional task participants had only to perform the primary task (space bisection). Our results showed enhanced auditory precision (and auditory weights) in the auditory attentional condition with respect to the control non-attentional condition. Interestingly in both conditions the multisensory results are well predicted by the MLE model. The results of this study support the idea that modality-specific attention modulates multisensory integration.

Abstract licence: CC BY

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