title: Sequential grouping of pure-tone percepts evoked by the segregation of components from a complex tone.
abstract: A sudden change applied to a single component can cause its segregation from an ongoing complex tone as a pure-tone-like percept. Three experiments examined whether such pure-tone-like percepts are organized into streams by extending the research of Bregman and Rudnicky (1975). Those authors found that listeners struggled to identify the presentation order of 2 pure-tone targets of different frequency when they were flanked by 2 lower frequency "distractors." Adding a series of matched-frequency "captor" tones, however, improved performance by pulling the distractors into a separate stream from the targets. In the current study, sequences of discrete pure tones were substituted by sequences of brief changes applied to an otherwise constant 1.2-s complex tone. Pure-tone-like percepts were evoked by applying 6-dB increments to individual components of a complex comprising harmonics 1-7 of 300 Hz (Experiment 1) or 0.5-ms changes in interaural time difference to individual components of a log-spaced complex (range 160-905 Hz; Experiment 2). Results were consistent with the earlier study, providing clear evidence that pure-tone-like percepts are organized into streams. Experiment 3 adapted Experiment 1 by presenting a global amplitude increment either synchronous with, or just after, the last captor prior to the 1st distractor. In the former case, for which there was no pure-tone-like percept corresponding to that captor, the captor sequence did not aid performance to the same extent as previously. It is concluded that this change to the captor-tone stream partially resets the stream-formation process, and so the distractors and targets became likely to integrate once more.
authors.affiliation: School of Life and Health Sciences, Aston University, Birmingham, England. nhaywood@audiospeech.ubc.ca
authors.forename: Nicholas R
authors.initials: NR
authors.lastname: Haywood
authors.forename: Brian
authors.initials: B
authors.lastname: Roberts
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology*; D004192:Discrimination, Psychological / Q000502:physiology*; D005364:Field Dependence-Independence; D006801:Humans; D046709:Pattern Recognition, Physiological / Q000502:physiology*; D010897:Pitch Discrimination / Q000502:physiology; D010898:Pitch Perception / Q000502:physiology*; D012016:Reference Values; D012691:Serial Learning / Q000502:physiology; D055815:Young Adult