Charles A. Harsin
Dept. of Psychol., Univ. of New Orleans, 2000 Lakeshore Dr., New Orleans, LA 70148
An investigation of the acoustic correlates of perceptual centers (p centers) in CV and VC syllables was conducted. Subjects located the p centers of the syllables by placing the syllables into perceptual isochrony with a series of 1000 Hz, 5-ms clicks. In all syllables the vowel was /a/. The CV syllables used the consonants /s/, /r/, /n/, /t/, /d/, /k/, and /g/, while the VC syllables used the consonants /s/, /r/, and /n/. Consonant duration was varied within each VC combination and within the CV combinations which did not begin with a stop. Energy modulations of between 3 and 42 Hz were extracted from the syllables and were weighted according to an acoustic modulation sensitivity function. The rate, magnitude, and location of energy modulations within the syllables were all found to affect p-center location. In each syllable, the largest energy modulation, which was associated with the vowel onset, had the greatest effect on p-center location. In CV syllables, the modulation associated with the consonant had a secondary effect, while in VC syllables the initial vowel modulation was apparently the only determinant of p-center location. The nature of the relevant modulation energy parameters suggests that they could be acting as information about velocities and/or accelerations of articulators, and that p-centers might signify an integration of multiple articulatory events into a single syllabic event.