Electronic Thesis and Dissertation Repository

Thesis Format

Monograph

Degree

Master of Science

Program

Neuroscience

Collaborative Specialization

Music Cognition

Supervisor

Macpherson, Ewan A.

Abstract

Spatial Selective Auditory Attention (SSAA) allows individuals to attend to a desired sound’s location in an acoustically rich environment. This research project explored the compensatory updating of SSAA focus during head movements and the roles of vestibular, proprioceptive, and visual self-motion signals in this process. A behavioural auditory selective attention task was conducted with and without visual cues and in three different motion conditions that manipulated the availability of vestibular and proprioceptive signals: Static (no updating required), Active head rotation (vestibular and proprioceptive signals available), and Passive whole-body rotation (only vestibular signals available). The findings suggest that listeners do appropriately update their SSAA while moving their heads, although with a slight frontal bias. Performance in the Passive condition was almost equal to the Active condition, indicating that vestibular signals were sufficient for SSAA updating, while proprioceptive signals were not necessary. Visual cues improved SSAA updating somewhat, but were not essential.

Summary for Lay Audience

Human beings exhibit a remarkable capacity to selectively attend to particular sounds of interest in complex and noisy environments. Nevertheless, this process of selective auditory attention goes beyond mere identification of sound location. In a world where everything, including ourselves, moves, we must constantly update our selective auditory attention to adapt to new sound locations. We are provided with some internal signals about our movement including vestibular and proprioceptive cues generated from our inner ear and neck muscles respectively. These cues enable our attentional ability called Spatially Selective Auditory Attention (SSAA) to be on duty. Yet, it is not clear which internal signal (vestibular or proprioceptive) is mainly responsible for continually updating our SSAA to a specific sound while we move our head’s direction during our everyday lives. In this research project we explored this question through a behavioral listening-attending task, in which individuals were required to update their focus of SSAA to a stationary target loudspeaker while undergoing voluntary (neck) or passive (whole-body) rotations.

Our findings suggest that among all the internal cues at our disposal, the signals generated by the vestibular system are dominant and sufficiently support our ability to update SSAA during movement, but that visual and proprioceptive signals did not play a necessary role in this process. This study pioneers the investigation of the weighting of internal cues on SSAA during motion.

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