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Effects of auditory feedback structure on adaptive and corrective responses in speech motor control
Poster Session E, Sunday, September 14, 11:00 am - 12:30 pm, Field House
Emily Tesch1, Ayoub Daliri1, Julie Liss1; 1Arizona State University
Objectives: Speech motor adaptation enables speakers to maintain accurate production despite sensory disruptions, yet the relationship between immediate (corrective) and sustained (adaptive) responses remains under-characterized. This study examined how structured auditory perturbations influence the magnitude of adaptive and corrective responses in speech motor control. Methods: Thirty right-handed native English-speaking adults (19 female, 11 male; ages 18+) with no reported neurological, hearing, or language impairments completed two experimental sessions. Participants were prompted to produce monosyllabic words containing the vowel /ɛ/ while receiving real-time auditory feedback through insert earphones. Across sessions, each participant experienced all four perturbation conditions, which varied by onset pattern (gradual vs. sudden) and feedback contingency (clamped vs. shifted). Perturbations were applied to the first (F1) and second (F2) formant frequencies to acoustically shift the vowel /ɛ/ (as in “head”) toward /æ/ (as in “had”). In clamped conditions, the altered feedback was fixed and unrelated to the speaker’s production. In shift conditions, feedback was modified relative to the speaker’s articulatory output within the trial. Gradual perturbations increased incrementally over trials; sudden perturbations were introduced in stepwise increments across trial blocks. Adaptive and corrective responses were extracted via acoustic analysis of F1 and F2 trajectories. Adaptive responses—reflecting feedforward control—were measured in the initial 25% of the vowel duration, prior to the availability of auditory feedback from the current trial. Corrective responses—reflecting feedback-based, online adjustments—were measured in the final 25% of the vowel duration. Results: Adaptive responses were larger in magnitude than corrective responses across all conditions. Both response types were slightly attenuated in the clamped feedback conditions compared to shifted feedback. There were no significant differences between gradual and sudden onset conditions for either response type. These results suggest that the relevance of auditory feedback, rather than the timing of perturbation onset, more strongly influences both adaptive and corrective control in speech. Conclusion: The structure of altered auditory feedback plays a critical role in shaping speech motor responses. Adaptive responses—reflecting feedforward control—were more robust than corrective responses, particularly under feedback conditions that maintained a meaningful relationship to the speaker’s output. These findings support models of speech motor control that differentiate between adaptive and corrective mechanisms and highlight the importance of feedback relevance in driving motor learning.
Topic Areas: Speech Motor Control,