Poster D104, Monday, March 27, 8:00 – 10:00 am, Pacific Concourse
Altered speech production in response to transient mid-utterance formant perturbation
Inez Raharjo1,2, Hardik Kothare1, John F. Houde1, Srikantan S. Nagarajan1; 1University of California, San Francisco, 2University of California, Berkeley
Listeners distinguish vowels by their formant frequencies, so speaking requires precise control of formants. To understand how this control works, and what the role of auditory feedback is in the process, previous studies have looked at the behavioral responses to an altered formant feedback. These studies show that people adapt when a consistent formant shift is applied during repeated productions of an entire word utterance. However, speakers’ responses to unexpected formant perturbations transiently applied at mid-utterance is not yet known, and may be relevant to understand online control of formants. To investigate this, we applied a real-time shift of the first formant frequency (F1) in the middle of participants’ utterance. We shifted F1 for only 400 ms after a jittered delay while participants phonated the word ‘head’ (vowel /ɛ/) for an entire 1.5 seconds. We found that participants immediately altered their F1 production at the onset of the perturbation. The magnitude of these responses were much smaller than the magnitude of the perturbation, and were smaller than responses seen in formant adaptation studies. Moreover, participants did not return to their baseline frequency at the end of the perturbation. The results of this study indicate that online feedback alteration may utilize a feedback error correction mechanism that is similar to what drives formant adaptation. Moreover, this suggests a time-dependence for the activation of speech error correction.
Topic Area: PERCEPTION & ACTION: Audition