title: Attentional modulation of informational masking on early cortical representations of speech signals.
abstract: To recognize speech in a noisy auditory scene, listeners need to perceptually segregate the target talker's voice from other competing sounds (stream segregation). A number of studies have suggested that the attentional demands placed on listeners increase as the acoustic properties and informational content of the competing sounds become more similar to that of the target voice. Hence we would expect attentional demands to be considerably greater when speech is masked by speech than when it is masked by steady-state noise. To investigate the role of attentional mechanisms in the unmasking of speech sounds, event-related potentials (ERPs) were recorded to a syllable masked by noise or competing speech under both active (the participant was asked to respond when the syllable was presented) or passive (no response was required) listening conditions. The results showed that the long-latency auditory response to a syllable (/bi/), presented at different signal-to-masker ratios (SMRs), was similar in both passive and active listening conditions, when the masker was a steady-state noise. In contrast, a switch from the passive listening condition to the active one, when the masker was two-talker speech, significantly enhanced the ERPs to the syllable. These results support the hypothesis that the need to engage attentional mechanisms in aid of scene analysis increases as the similarity (both acoustic and informational) between the target speech and the competing background sounds increases.
authors.affiliation: Department of Psychology, Speech and Hearing Research Center, McGovern Institute for Brain Research at PKU, Key Laboratory on Machine Perception (Ministry of Education), Peking University, Beijing, China.
authors.forename: Changxin
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Rotman Research Institute, Baycrest Centre, Toronto, Ontario, Canada.
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Arnott
authors.affiliation: Department of Psychology, Human Communication Laboratory, University of Toronto Mississauga, Mississauga, Ontario, Canada.
authors.forename: Cristina
authors.initials: C
authors.lastname: Rabaglia
authors.affiliation: Department of Psychology, Human Communication Laboratory, University of Toronto Mississauga, Mississauga, Ontario, Canada.
authors.forename: Meital
authors.initials: M
authors.lastname: Avivi-Reich
authors.affiliation: Department of Psychology, Human Communication Laboratory, University of Toronto Mississauga, Mississauga, Ontario, Canada.
authors.forename: James
authors.initials: J
authors.lastname: Qi
authors.affiliation: Department of Psychology, Speech and Hearing Research Center, McGovern Institute for Brain Research at PKU, Key Laboratory on Machine Perception (Ministry of Education), Peking University, Beijing, China.
authors.forename: Xihong
authors.initials: X
authors.lastname: Wu
authors.affiliation: Department of Psychology, Speech and Hearing Research Center, McGovern Institute for Brain Research at PKU, Key Laboratory on Machine Perception (Ministry of Education), Peking University, Beijing, China. Electronic address: liangli@pku.edu.cn.
authors.forename: Liang
authors.initials: L
authors.lastname: Li
authors.affiliation: Department of Psychology, Human Communication Laboratory, University of Toronto Mississauga, Mississauga, Ontario, Canada. Electronic address: bruce.schneider@utoronto.ca.
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Schneider
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000465:Algorithms; D001288:Attention; D001307:Auditory Perception; D005071:Evoked Potentials; D005260:Female; D006801:Humans; D007802:Language; D008297:Male; D009622:Noise; D010470:Perceptual Masking; D010700:Phonetics; D011571:Psychoacoustics; D013060:Speech / Q000502:physiology*; D013067:Speech Perception; D055815:Young Adult
keywords: Attention; Energetic masking; Event-related potentials; Informational masking