Effects of Spatial Speech Presentation on Listener Response Strategy for Talker-Identification.

Sebastian Möller,Stefan Uhrig,Andrew Perkis,Dawn M. Behne,U. Peter Svensson

doi:10.3389/fnins.2021.730744

Abstract

This study investigates effects of spatial auditory cues on human listeners' response strategy for identifying two alternately active talkers (“turn-taking” listening scenario). Previous research has demonstrated subjective benefits of audio spatialization with regard to speech intelligibility and talker-identification effort. So far, the deliberate activation of specific perceptual and cognitive processes by listeners to optimize their task performance remained largely unexamined. Spoken sentences selected as stimuli were either clean or degraded due to background noise or bandpass filtering. Stimuli were presented via three horizontally positioned loudspeakers: In a non-spatial mode, both talkers were presented through a central loudspeaker; in a spatial mode, each talker was presented through the central or a talker-specific lateral loudspeaker. Participants identified talkers via speeded keypresses and afterwards provided subjective ratings (speech quality, speech intelligibility, voice similarity, talker-identification effort). In the spatial mode, presentations at lateral loudspeaker locations entailed quicker behavioral responses, which were significantly slower in comparison to a talker-localization task. Under clean speech, response times globally increased in the spatial vs. non-spatial mode (across all locations); these “response time switch costs,” presumably being caused by repeated switching of spatial auditory attention between different locations, diminished under degraded speech. No significant effects of spatialization on subjective ratings were found. The results suggested that when listeners could utilize task-relevant auditory cues about talker location, they continued to rely on voice recognition instead of localization of talker sound sources as primary response strategy. Besides, the presence of speech degradations may have led to increased cognitive control, which in turn compensated for incurring response time switch costs.

Highlights

The ability of the human auditory system for rapid extraction of spatial auditory cues is thought to facilitate perceptual and cognitive speech processing, especially under adverse and dynamic listening conditions (Zekveld et al, 2014; Koelewijn et al, 2015)
Significant main effects of speech degradation resulted for all four subjective constructs: Speech quality [F(2, 62) = 1η3p15G2
Task difficulty should most probably depend on the amount of allocated information processing resources [i.e., the perceptual-cognitive load (Wickens, 2008); measurable, e.g., by pupillometry or EEG] to discriminate between the two talkers’ voices, which was higher for degraded vs. clean speech; better talker voice discriminability would in turn ease TI based on voice recognition

Summary

Introduction

The ability of the human auditory system for rapid extraction of spatial auditory cues is thought to facilitate perceptual and cognitive speech processing, especially under adverse and dynamic listening conditions (Zekveld et al, 2014; Koelewijn et al, 2015). Past research usually centered around listening situations involving multiple, simultaneously active talkers. The present study addresses another kind of listening situation in dyadic human–human conversation, namely when two talkers take turns in active speaking time (with silence gaps in between). What are their underlying perceptual and cognitive processes? To what extent are such effects dependent on speech degradations as well as impacting various attributes of subjective listening experience like perceived speech quality, speech intelligibility, or talker-identification effort?1 Does auditory information cuing talker location affect behavioral talker-identification (TI) performance in this “turn-taking” listening scenario (Lin and Carlile, 2015, 2019)? If significant effects exist, what are their underlying perceptual and cognitive processes? To what extent are such effects dependent on speech degradations as well as impacting various attributes of subjective listening experience like perceived speech quality, speech intelligibility, or talker-identification effort?1

Methods

Results

Discussion

Conclusion