title: Between-Frequency and Between-Ear Gap Detections and Their Relation to Perception of Stop Consonants.
abstract: OBJECTIVE
  The objective of this study was to examine the hypothesis that between-channel gap detection, which includes between-frequency and between-ear gap detection, and perception of stop consonants, which is mediated by the length of voice-onset time (VOT), share common mechanisms, namely relative-timing operation in monitoring separate perceptual channels.
  
  
  METHODS
  The authors measured gap detection thresholds and identification functions of /ba/ and /pa/ along VOT in 49 native young adult Japanese listeners. There were three gap detection tasks. In the between-frequency task, the leading and trailing markers differed in terms of center frequency (Fc). The leading marker was a broadband noise of 10 to 20,000 Hz. The trailing marker was a 0.5-octave band-passed noise of 1000-, 2000-, 4000-, or 8000-Hz Fc. In the between-ear task, the two markers were spectrally identical but presented to separate ears. In the within-frequency task, the two spectrally identical markers were presented to the same ear. The /ba/-/pa/ identification functions were obtained in a task in which the listeners were presented synthesized speech stimuli of varying VOTs from 10 to 46 msec and asked to identify them as /ba/ or /pa/.
  
  
  RESULTS
  The between-ear gap thresholds were significantly positively correlated with the between-frequency gap thresholds (except those obtained with the trailing marker of 4000-Hz Fc). The between-ear gap thresholds were not significantly correlated with the within-frequency gap thresholds, which were significantly correlated with all the between-frequency gap thresholds. The VOT boundaries and slopes of /ba/-/pa/ identification functions were not significantly correlated with any of these gap thresholds.
  
  
  CONCLUSIONS
  There was a close relation between the between-ear and between-frequency gap detection, supporting the view that these two types of gap detection share common mechanisms of between-channel gap detection. However, there was no evidence for a relation between the perception of stop consonants and the between-frequency/ear gap detection in native Japanese speakers.
authors.affiliation: 1Department of Informatics, Faculty of Information Science and Electrical Engineering, Kyushu University, Fukuoka, Japan; and 2Pioneer Corporation, Tokyo, Japan.
authors.forename: Shuji
authors.initials: S
authors.lastname: Mori
authors.forename: Kazuki
authors.initials: K
authors.lastname: Oyama
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Kikuchi
authors.forename: Takako
authors.initials: T
authors.lastname: Mitsudo
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Hirose
mesh_terms: D000328:Adult; D001307:Auditory Perception / Q000502:physiology; D001309:Auditory Threshold; D005260:Female; D006801:Humans; D008297:Male; D010898:Pitch Perception / Q000502:physiology*; D013067:Speech Perception / Q000502:physiology*; D055815:Young Adult