Compensatory and adaptive responses to real-time formant shifts in adults and children

Auditory feedback plays an important role in speech motor learning, yet, little is known about the strength of motor learning and feedback control in speech development. This study investigated compensatory and adaptive responses to auditory feedback perturbation in children (aged 4-9 years old) and young adults (aged 18-29 years old). Auditory feedback was perturbed by near-real-time shifting F1 and F2 of the vowel /ɪː/ during the production of consonant-vowel-consonant words. Children were able to compensate and adapt in a similar or larger degree compared to young adults. Higher token-to-token variability was found in children compared to adults but not disproportionately higher during the perturbation phases compared to the unperturbed baseline. The added challenge to auditory-motor integration did not influence production variability in children, and compensation and adaptation effects were found to be strong and sustainable. Significant group differences were absent in the proportions of speakers displaying a compensatory or adaptive response, an amplifying response, or no consistent response. Within these categories, children produced significantly stronger compensatory, adaptive, or amplifying responses, which could be explained by less-ingrained existing representations. The results are interpreted as both auditory-motor integration and learning capacities are stronger in young children compared to adults.