Effects of a consistent target or masker voice on target speech intelligibility in two- and three-talker mixtures

Abstract

When the spatial location or identity of a sound is held constant, it is not masked as effectively by competing sounds. This suggests that experience with a particular voice over time might facilitate perceptual organization in multitalker environments. The current study examines whether listeners benefit from experience with a voice only when it is the target, or also when it is a masker, using diotic presentation and a closed-set task (coordinate response measure). A reliable interaction was observed such that, in two-talker mixtures, consistency of masker or target voice over 3–7 trials significantly benefited target recognition performance, whereas in three-talker mixtures, target, but not masker, consistency was beneficial. Overall, this work suggests that voice consistency improves intelligibility, although somewhat differently when two talkers, compared to three talkers, are present, suggesting that consistent-voice information facilitates intelligibility in at least two different ways. Listeners can use a template-matching strategy to extract a known voice from a mixture when it is the target. However, consistent-voice information facilitates segregation only when two, but not three, talkers are present.

Can we prepare to attend to one of two simultaneous voices?

“…In this case the benefit was clearly due to exogenous priming of attention to a voice. Samson and Johnsrude (2016), using the call-sign paradigm, kept the target voice or the masker voice consistent for random sequences of between three and seven trials and found an improvement through a consistent run, though participants were largely unaware of the voice repetitions; again this (especially the effect of masker consistency) seems unlikely to reflect endogenous orienting to a voice.…”

The Effects of Switching Non-Spatial Attention During Conversational Turn Taking

“…Firstly, switching costs could be due to the process of re-engaging attention to a new target voice. Previous studies have shown that continuity in voice benefits selective attention 9,17,21,22 . A consistent voice provides the auditory system with an acoustic template, which assists in the extraction of a matching talker 21 .…”

“…This study investigated the acoustic and cognitive demands of non-spatial attention switching in the context of a conversation. Previous studies have examined the recall of only a limited number of items, usually digits or singular words, following a change in voice 21,22,24–26 . Here we probed the recall of two whole sentences (8 items) before and after a turn taking gap.…”

“…Previous studies have shown that voice consistency between trials 17,21 and within trials 9,22 can enhance target intelligibility in multi-talker mixtures. Samson and Johnsrude 21 showed, using co-ordinate response measure (CRM) speech 23 , that a target voice provides the auditory system with a template which guides listeners in extracting a repeating talker. Similarly, Bressler and Colleagues 22 showed using digits embedded in time reversed speech, that this biasing/enhancement of a consistent voice happens automatically without awareness or intention.…”

“…The first experiment aimed to establish the perceptual cost of a change in target voice. We expected enhanced performance with a repeating voice due to repetition priming effects 21,24–26 and a reduction in the accuracy of word recall and increase in errors following a voice switch due to disruption to streaming 9,22 . In addition, we aimed to further isolate which component of streaming was disrupted by looking at the process of disengagement vs re-engagement of attention around a turn taking gap.…”