Sensorimotor adaptation to acoustic perturbations in vowel formants

Abstract

The goal of this research is to study the auditory component of feedback control in speech production. This experiment investigates auditory sensorimotor adaptation (SA) as it relates to speech production: the process by which speakers alter their speech production in order to compensate for perturbations of their normal auditory feedback. Specifically, the first formant frequency (F1) was shifted in the auditory feedback heard by naive adult subjects as they produced vowels in single syllable words. Initial results indicate that subjects demonstrate compensatory formant shifts in their speech. This compensation was also present after training when acoustic feedback was masked by noise. This suggests that internal models used in the control of speech movements can be constantly updated by auditory feedback. These results in voiced speech are consistent with results from Houde and Jordan [Science 279, 1213–1216 (1998)], which demonstrated SA in whispered speech. A second study, currently underway, investigates perceptual discrimination of vowel stimuli differing in F1 frequency, using the same subjects as in the SA studies. Cross-subject relations between discrimination scores and extent of compensation will be presented and discussed. [Work supported by NIDCD Grant R01-DC01925.]