The Influence of Tactile Cognitive Maps on Auditory Space Perception in Sighted Persons.

Alessia Tonelli,Luca Brayda,Monica Gori

doi:10.3389/fpsyg.2016.01683

Abstract

We have recently shown that vision is important to improve spatial auditory cognition. In this study, we investigate whether touch is as effective as vision to create a cognitive map of a soundscape. In particular, we tested whether the creation of a mental representation of a room, obtained through tactile exploration of a 3D model, can influence the perception of a complex auditory task in sighted people. We tested two groups of blindfolded sighted people – one experimental and one control group – in an auditory space bisection task. In the first group, the bisection task was performed three times: specifically, the participants explored with their hands the 3D tactile model of the room and were led along the perimeter of the room between the first and the second execution of the space bisection. Then, they were allowed to remove the blindfold for a few minutes and look at the room between the second and third execution of the space bisection. Instead, the control group repeated for two consecutive times the space bisection task without performing any environmental exploration in between. Considering the first execution as a baseline, we found an improvement in the precision after the tactile exploration of the 3D model. Interestingly, no additional gain was obtained when room observation followed the tactile exploration, suggesting that no additional gain was obtained by vision cues after spatial tactile cues were internalized. No improvement was found between the first and the second execution of the space bisection without environmental exploration in the control group, suggesting that the improvement was not due to task learning. Our results show that tactile information modulates the precision of an ongoing space auditory task as well as visual information. This suggests that cognitive maps elicited by touch may participate in cross-modal calibration and supra-modal representations of space that increase implicit knowledge about sound propagation.

Highlights

Several studies show that vision is essential in the domain of space perception influencing other sensory modalities
Previous studies (Bruns and Röder, 2010b; Gori et al, 2014b) demonstrated how direct tactile stimuli can influence auditory perception, this is the first study showing that the sense of touch, through active exploration of a surrounding environment and of its 3D map, can indirectly influence complex audio-spatial tasks that are known to benefit from previous environmental knowledge
This work contributes to argue that spatial representations are unlinked to specific sensory modalities and that cross-modal calibration contributes to build supra-modal mental representations

Summary

Introduction

Several studies show that vision is essential in the domain of space perception influencing other sensory modalities. Tactile Maps Influence Auditory Perception phenomenon is known as Ventriloquist effect (Bertelson and Radeau, 1981; Warren et al, 1981). The brain has to infer the direction of sound sources by taking into account the relative intensity of sound received at each ear as well as the time delay between arrival at the two ears in the superior olivary complex (Middlebrooks and Green, 1991). For this reason the auditory system is normally less accurate and reliable in spatial representation, compared with the visual system. Tactile stimulation influences the auditory cortical activity through higher areas assigned to multimodal association (Bruns and Röder, 2010a)

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Results

Conclusion