Musically tone-deaf individuals have difficulty discriminating intonation contours extracted from speech.
Musically tone-deaf individuals have psychophysical deficits in detecting pitch changes, yet their discrimination of intonation contours in speech appears to be normal. One hypothesis for this dissociation is that intonation contours use coarse pitch contrasts which exceed the pitch-change detection thresholds of tone-deaf individuals (). We test this idea by presenting intonation contours for discrimination, both in the context of the original sentences in which they occur and in a "pure" form dissociated from any phonetic context. The pure form consists of gliding-pitch analogs of the original intonation contours which exactly follow their pattern of pitch and timing. If the spared intonation perception of tone-deaf individuals is due to the coarse pitch contrasts of intonation, then such individuals should discriminate the original sentences and the gliding-pitch analogs equally well. In contrast, we find that discrimination of the gliding-pitch analogs is severely degraded. Thus it appears that the dissociation between spoken and musical pitch perception in tone-deaf individuals is due to a deficit at a higher level than simple pitch-change detection.
Patel
Aniruddh D
AD
The Neurosciences Institute, San Diego, CA, USA. apatel@nsi.edu
Foxton
Jessica M
JM
Griffiths
Timothy D
TD
D000328:Adult; D000368:Aged; D001309:Auditory Threshold / Q000502:physiology*; D004192:Discrimination, Psychological / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D010897:Pitch Discrimination / Q000502:physiology*; D011601:Psychophysics; D013067:Speech Perception / Q000502:physiology*