ASA 125th Meeting Ottawa 1993 May

4pSP11. A preliminary test of prototype theory for a [ba]-to-[da] continuum.

Joan E. Sussman

Dept. of Commun. Disord. and Sci., State Univ. of New York at Buffalo, Buffalo, NY 14260

Ten listeners participated in identification, overt prototype [A. Samuel, Percept. Psychophys. 82, 307--314 (1982)] and selective adaptation tasks for a 15-item continuum. Stimuli varied linearly by 90- and 178-Hz steps of formant frequency transition onsets for the second and third resonances, respectively. The prototype was defined as the ``best example of ba'' with `best' explained per Samuel [1982, p. 309]. Results showed significant intra- and inter-subject variability for prototype choice. Each subject consistently chose his/her prototype on average 39% of the time, ranging from 20%--53%. Subjects chose stimuli 2--8 as prototypes, with the highest number (3) choosing stimulus 3 along the continuum. Further, contrary to Samuel's (1982) results for a [ga]--[ka] continuum, the greatest selective adaptation shift was obtained for the most extreme [ba] adaptor (average shift of 8.7%), with the prototype (average shift of 6.5%) and boundary adaptors (average 5.3% shift) resulting in smaller shifts. Results including reaction time data, will be related to prototype theory for consonant categories.