ASA 129th Meeting - Washington, DC - 1995 May 30 .. Jun 06

5pSC1. Interactions between acoustic dimensions contributing to the perception of voicing.

Michael D. Hall

Katharine Davis

Patricia K. Kuhl

Dept. of Speech and Hear. Sci., WJ-10, Univ. of Washington, Seattle, WA 98195

It is well known that several dimensions contribute to the classification of stop consonants as voiced or voiceless. Three Garner speeded classification experiments evaluated the nature of perceptual interactions between such dimensions. Specifically, the experiments examined the potential integrality between pairs of three critical dimensions---voice onset time (VOT), aspiration amplitude, and fundamental frequency (F0) at the onset of voicing. Only within-category (/ka/) syllable stimuli were used to eliminate phonetic classification as a basis for subjects' responses. Evidence was found for the asymmetric separability of VOT and F0; while variability along F0 significantly influenced VOT classification speed, variability along VOT did not similarly influence F0 classification. A similar pattern of asymmetric separability for F0 and aspiration amplitude was demonstrated, where aspiration variability did not interfere with F0 classification. In contrast, VOT and aspiration amplitude were completely integral, with variability along either dimension influencing classification speed along the other dimension. Furthermore, performance accuracy reflected a time-intensity trade-off between perception of VOT and aspiration. The results indicate that F0 and VOT/aspiration amplitude may contribute to two distinct sets of perceptual analyzers. Implications for phoneme perception will be discussed. [Work supported by NIH.]