title: Attentional Capacity Limits Gap Detection during Concurrent Sound Segregation.
abstract: Detecting a brief silent interval (i.e., a gap) is more difficult when listeners perceive two concurrent sounds rather than one in a sound containing a mistuned harmonic in otherwise in-tune harmonics. This impairment in gap detection may reflect the interaction of low-level encoding or the division of attention between two sound objects, both of which could interfere with signal detection. To distinguish between these two alternatives, we compared ERPs during active and passive listening with complex harmonic tones that could include a gap, a mistuned harmonic, both features, or neither. During active listening, participants indicated whether they heard a gap irrespective of mistuning. During passive listening, participants watched a subtitled muted movie of their choice while the same sounds were presented. Gap detection was impaired when the complex sounds included a mistuned harmonic that popped out as a separate object. The ERP analysis revealed an early gap-related activity that was little affected by mistuning during the active or passive listening condition. However, during active listening, there was a marked decrease in the late positive wave that was thought to index attention and response-related processes. These results suggest that the limitation in detecting the gap is related to attentional processing, possibly divided attention induced by the concurrent sound objects, rather than deficits in preattentional sensory encoding.
authors.affiliation: University of Alberta.|Rotman Research Institute, Baycrest Centre for Geriatric Care, Toronto, Canada.
authors.forename: Ada W S
authors.initials: AW
authors.lastname: Leung
authors.affiliation: Université de Montréal.|Centre de Recherche en Neuropsychologie et Cognition (CERNEC), Montréal, Canada.|BRAMS (International Laboratory for Brain, Music, and Sound Research), Montréal, Canada.|Centre de Recherche de l'Institut Universitaire de Gériatrie de Montréal (CRIUGM).
authors.forename: Pierre
authors.initials: P
authors.lastname: Jolicoeur
authors.affiliation: Rotman Research Institute, Baycrest Centre for Geriatric Care, Toronto, Canada.|University of Toronto.
authors.forename: Claude
authors.initials: C
authors.lastname: Alain
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology*; D001307:Auditory Perception / Q000502:physiology*; D001931:Brain Mapping; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D011930:Reaction Time / Q000502:physiology; D017603:Signal Detection, Psychological / Q000502:physiology*; D013016:Sound; D055815:Young Adult