Sensorimotor adaptation of pitch for prosody (Dahl et al., 2024)

Purpose: This study examined how speakers adapt to fundamental frequency (f_o) errors that affect the use of prosody to convey linguistic meaning, whether f_o adaptation in that context relates to adaptation in linguistically neutral sustained vowels, and whether cue trading is reflected in responses in the prosodic cues of f_o and amplitude.

Method: Twenty-four speakers said vowels and sentences while f_o was digitally altered to induce predictable errors. Shifts in f_o (±200 cents) were applied to the entire sustained vowel and one word (emphasized or unemphasized) in sentences. Two prosodic cues— f_o and amplitude—were extracted. The effects of f_o shifts, shift direction, and emphasis on f_o response magnitude were evaluated with repeated-measures analyses of variance. Relationships between adaptive f_o responses in sentences and vowels and between adaptive f_o and amplitude responses were evaluated with Spearman correlations.

Results: Speakers adapted to f_o errors in both linguistically meaningful sentences and linguistically neutral vowels. Adaptive f_o responses of unemphasized words were smaller than those of emphasized words when f_o was shifted upward. There was no relationship between adaptive f_o responses in vowels and emphasized words, but adaptive f_o and amplitude responses were strongly, positively correlated.

Conclusions: Sensorimotor adaptation occurs in response to f_o errors regardless of how disruptive the error is to linguistic meaning. Adaptation to f_o errors during sustained vowels may not involve the exact same mechanisms as sensorimotor adaptation as it occurs in meaningful speech. The relationship between adaptive responses in f_o and amplitude supports an integrated model of prosody.

Supplemental Material S1. Group mean adaptive response in amplitude to downward (Panel A) and upward (Panel B) shifts in auditory feedback of f_o (±200 cents) during emphasized (blue) and unemphasized (dashed pink) words in running speech. Shaded areas are 95% confidence intervals.

Supplemental Material S2. Group mean adaptive response in amplitude to a 200-cent downward shift in auditory feedback of f_o during sustained vowels. Shaded area is 95% confidence interval.

Supplemental Material S3. Results of repeated-measures analyses of variance for normalized fundamental frequency (f_o) during sustained vowels and sentences with emphasized and unemphasized words, based on data extracted from the entire vowel/word (full window).

Dahl, K. L., Cádiz, M. D., Zuk, J., Guenther, F. H., & Stepp, C. E. (2024). Controlling pitch for prosody: Sensorimotor adaptation in linguistically meaningful contexts. Journal of Speech, Language, and Hearing Research, 67(2), 440–454. https://doi.org/10.1044/2023_JSLHR-23-00460