Sensorimotor adaptation to feedback perturbations of vowel acoustics and its relation to perception

Abstract

The role of auditory feedback in speech motor control was explored in three related experiments. Experiment 1 investigated auditory sensorimotor adaptation: the process by which speakers alter their speech production to compensate for perturbations of auditory feedback. When the first formant frequency (F1) was shifted in the feedback heard by subjects as they produced vowels in consonant-vowel-consonant (CVC) words, the subjects' vowels demonstrated compensatory formant shifts that were maintained when auditory feedback was subsequently masked by noise-evidence of adaptation. Experiment 2 investigated auditory discrimination of synthetic vowel stimuli differing in F1 frequency, using the same subjects. Those with more acute F1 discrimination had compensated more to F1 perturbation. Experiment 3 consisted of simulations with the directions into velocities of articulators model of speech motor planning, which showed that the model can account for key aspects of compensation. In the model, movement goals for vowels are regions in auditory space; perturbation of auditory feedback invokes auditory feedback control mechanisms that correct for the perturbation, which in turn causes updating of feedforward commands to incorporate these corrections. The relation between speaker acuity and amount of compensation to auditory perturbation is mediated by the size of speakers' auditory goal regions, with more acute speakers having smaller goal regions.

Cortical interactions underlying the production of speech sounds

“…In this study (Villacorta, Perkell, & Guenther, 2004;Villacorta, 2005), 20 subjects performed a psychophysical experiment that involved four phases: (1) a baseline phase, in which the subject produced 15 repetitions of a short list of words with normal auditory feedback (each repetition of the list corresponding to one epoch), (2) a ramp phase, during which a shift in F1 was gradually introduced to the subject's auditory feedback (epochs 16-20), (3) a training phase, in which the full F1 perturbation (a 30% shift of F1) was applied on every trial (epochs 21-45), and (4) a post-test phase in which the subject received unaltered auditory feedback (epochs 46-65). The subjects' adaptive response (i.e., the percent change in F1 compared to the baseline phase in the direction opposite the perturbation) is shown by the solid line with standard error bars in Fig.…”

“…The shaded band in Fig. 7 represents the 95% confidence interval for simulations of the DIVA model performing the same experiment (see Villacorta, 2005, for details). With the exception of only one epoch in the ramp phase (denoted by a filled circle in Fig.…”

Modulation of auditory-motor learning in response to formant perturbation as a function of delayed auditory feedback

“…When specific characteristics of the auditory feedback of a speakers' speech are modified in real time, speakers change specific aspects of their speech production to compensate for the perceived error (i.e., both online correction and auditory-motor learning). This has been demonstrated for speaking amplitude (e.g., Bauer et al, 2006), vocal frequency (e.g., Burnett et al, 1998;Jones and Munhall, 2000;Larson et al, 2007), fricative spectrum (Shiller et al, 2009;Casserly, 2011), and vowel resonances/formants (e.g., Houde and Jordan, 1998;Purcell and Munhall, 2006;Villacorta et al, 2007, Mitsuya et al, 2015.…”

Predicting head-marking variability in Yucatec Maya relative clause production

“…A learning account along these lines has the theoretical advantage that it would not require speakers to continuously simulate their interlocutors. It receives empirical support from research on articulation suggesting that speakers monitor themselves, and integrate their own feedback into their later productions (e.g., Houde, 1998 ;Tourville, Reilly, & Guenther, 2008 ;Villacorta, Perkell, & Guenther, 2007). At the level of grammatical encoding, research on this question is still largely lacking; some initial support comes from a study by Roche, Dale, and Kreuz ( 2010 ), who found that English speakers in an interactive dialogue-based task were more likely to adjust their productions to avoid syntactic ambiguity when their previous productions were not communicatively successful.…”