Abstract
Human sound localization abilities rely on binaural and spectral cues. Spectral cues arise from interactions between the sound wave and the listener's body (head-related transfer function, HRTF). Large individual differences were reported in localization abilities, even in young normal-hearing adults. Several studies have attempted to determine whether localization abilities depend mostly on acoustical cues or on perceptual processes involved in the analysis of these cues. These studies have yielded inconsistent findings, which could result from methodological issues. In this study, we measured sound localization performance with normal and modified acoustical cues (i.e., with individual and non-individual HRTFs, respectively) in 20 naïve listeners. Test conditions were chosen to address most methodological issues from past studies. Procedural training was provided prior to sound localization tests. The results showed no direct relationship between behavioral results and an acoustical metrics (spectral-shape prominence of individual HRTFs). Despite uncertainties due to technical issues with the normalization of the HRTFs, large acoustical differences between individual and non-individual HRTFs appeared to be needed to produce behavioral effects. A subset of 15 listeners then trained in the sound localization task with individual HRTFs. Training included either visual correct-answer feedback (for the test group) or no feedback (for the control group), and was assumed to elicit perceptual learning for the test group only. Few listeners from the control group, but most listeners from the test group, showed significant training-induced learning. For the test group, learning was related to pre-training performance (i.e., the poorer the pre-training performance, the greater the learning amount) and was retained after 1 month. The results are interpreted as being in favor of a larger contribution of perceptual factors than of acoustical factors to sound localization abilities with virtual sources.
Highlights
Individuals receive information about their environment mainly via the visual and auditory sensory modalities
Auditory space perception relies on the processing of binaural cues for the left/right dimension, and spectral cues for the up/down and front/back dimensions
An improvement of performance for the first group would be in favor of a contribution of perceptual factors to sound localization abilities with virtual sources, because acoustical factors were constant during training
Summary
Individuals receive information about their environment mainly via the visual and auditory sensory modalities. Auditory space perception relies on the processing of binaural cues (i.e., interaural differences in the level and time of arrival of the incoming sound wave) for the left/right dimension, and spectral cues (i.e., filtering of the incoming sound wave by the listener’s upper body, which corresponds to the head-related transfer function, HRTF) for the up/down and front/back dimensions. These direction-dependent cues are transformed into a complex audio-spatial map, which depends on anatomical characteristics and develops through experience with sensory—mainly visual (King, 2009)—feedback. Experience-dependent plasticity provides a potential neural basis for training-induced perceptual improvements in performance
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
