Session Perception V:

Perception V: Cue Use

Type: oral
Chair: Asher Laufer
Date: Thursday - August 09, 2007
Time: 13:20
Room: 6 (Black)

 

Perception V-1 CLARIFYING THE SPEECH PERCEPTION DEFICIT IN DYSLEXIC CHILDREN
Souhila MESSAOUD-GALUSI, University College London - Department of Phonetics and Linguistics
Valerie HAZAN, University College London - Department of Phonetics and Linguistics
Stuart ROSEN, University College London - Department of Phonetics and Linguistics
Paper File
  It has often been claimed that dyslexic children show deficits in various speech-perceptual tasks. In this study, dyslexic and chronological-age-matched control children were asked to identify words, and label monosyllables from a voiced/voiceless plosive continuum, in quiet and in noise. Correlations on these tasks with reading and reading-related skills were weak and about half of dyslexic children had categorization slopes within the normal range in quiet. Both reading groups performed similarly well for labeling in noise and when identifying words in noise. The identification of words in noise was found to be related neither to reading nor to the consistency of categorical labeling. This study confirms that only a subgroup of children with dyslexia appears to have speech-perceptual deficits.
Perception V-2 Within category phonetic variability affects perceptual uncertainty
Meghan Clayards, University of Rochester
Richard N. Aslin, University of Rochester
Michael K. Tanenhaus, University of Rochester
Robert Jacobs, University of Rochester
Paper File
  We explored a mechanism for adjustments in the perceptual weighting of multiple probabilistic cues in speech. Subjects heard words that varied along a voice onset time (VOT) continuum (eg. “beach” to “peach”) while performing a two alternative forced choice task (2AFC). For one group the VOT values that they heard came from distributions with wide variance (wide group) around the category prototype and for the other group they came from distributions with narrow variance (narrow group). The slope of the labeling response curve was shallower for the wide group indicating greater perceptual uncertainty. This suggests that listeners are sensitive to the reliability of an acoustic cue when making category judgments and can rapidly adjust cue-weights in response to cue-reliability.
Perception V-3 THE EFFECT OF AGE ON ACOUSTIC CUE WEIGHTING IN THE PERCEPTION OF INITIAL STOP VOICING CONTRAST IN HEBREW
Riki Taitelbaum-Swead , Department of Communication Disorders, Sackler Faculty of Medicine,Tel-Aviv University ,ISRAEL
Minka Hildesheimer, Department of Communication Disorders, Sackler Faculty of Medicine,Tel-Aviv University ,ISRAEL
Liat Kishon-Rabin , Department of Communication Disorders, Sackler Faculty of Medicine,Tel-Aviv University
Paper File
  Listeners use several acoustic cues with different relative weighting, for perceiving a phonetic contrast. The weighting depends on variables such as age and language. The purpose of this study was to examine the relative weighting of some acoustic cues to the perception of initial voicing of plosives in different age groups. Three groups of children and one group of adults, Hebrew speakers were evaluated. The relative weighting of three cues were tested: Voice Onset Time (VOT), initial burst, and the transitions to the following vowel. A similar hierarchy of cues was found in all groups, with VOT the primary one, although not in the same weighting. Adults give more weight to transitions and burst compared to children. These findings indicate the ability of the auditory system to focus on the important cues already at young age. However, there appears to be a continued shift in the weighting during development.

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