title: Manipulations of listeners' echo perception are reflected in event-related potentials.
abstract: To gain information from complex auditory scenes, it is necessary to determine which of the many loudness, pitch, and timbre changes originate from a single source. Grouping sound into sources based on spatial information is complicated by reverberant energy bouncing off multiple surfaces and reaching the ears from directions other than the source's location. The ability to localize sounds despite these echoes has been explored with the precedence effect: Identical sounds presented from two locations with a short stimulus onset asynchrony (e.g., 1-5 ms) are perceived as a single source with a location dominated by the lead sound. Importantly, echo thresholds, the shortest onset asynchrony at which a listener reports hearing the lag sound as a separate source about half of the time, can be manipulated by presenting sound pairs in contexts. Event-related brain potentials elicited by physically identical sounds in contexts that resulted in listeners reporting either one or two sources were compared. Sound pairs perceived as two sources elicited a larger anterior negativity 100-250 ms after onset, previously termed the object-related negativity, and a larger posterior positivity 250-500 ms. These results indicate that the models of room acoustics listeners form based on recent experience with the spatiotemporal properties of sound modulate perceptual as well as later higher-level processing.
authors.affiliation: Neuroscience and Behavior Program, Department of Psychology, University of Massachusetts, Amherst, Massachusetts 01003, USA. lsanders@psych.umass.edu
authors.forename: Lisa D
authors.initials: LD
authors.lastname: Sanders
authors.forename: Benjamin H
authors.initials: BH
authors.lastname: Zobel
authors.forename: Richard L
authors.initials: RL
authors.lastname: Freyman
authors.forename: Rachel
authors.initials: R
authors.lastname: Keen
mesh_terms: D000161:Acoustic Stimulation; D000162:Acoustics; D000328:Adult; D001299:Audiometry; D001306:Auditory Pathways / Q000502:physiology*; D001307:Auditory Perception; D001309:Auditory Threshold; D004569:Electroencephalography; D005072:Evoked Potentials, Auditory; D005160:Facility Design and Construction; D005260:Female; D006801:Humans; D009038:Motion; D010470:Perceptual Masking; D011571:Psychoacoustics; D011930:Reaction Time; D017603:Signal Detection, Psychological; D013016:Sound; D013017:Sound Localization; D013018:Sound Spectrography; D013997:Time Factors; D055815:Young Adult