title: Sensorimotor influences on speech perception in infancy.
abstract: The influence of speech production on speech perception is well established in adults. However, because adults have a long history of both perceiving and producing speech, the extent to which the perception-production linkage is due to experience is unknown. We addressed this issue by asking whether articulatory configurations can influence infants' speech perception performance. To eliminate influences from specific linguistic experience, we studied preverbal, 6-mo-old infants and tested the discrimination of a nonnative, and hence never-before-experienced, speech sound distinction. In three experimental studies, we used teething toys to control the position and movement of the tongue tip while the infants listened to the speech sounds. Using ultrasound imaging technology, we verified that the teething toys consistently and effectively constrained the movement and positioning of infants' tongues. With a looking-time procedure, we found that temporarily restraining infants' articulators impeded their discrimination of a nonnative consonant contrast but only when the relevant articulator was selectively restrained to prevent the movements associated with producing those sounds. Our results provide striking evidence that even before infants speak their first words and without specific listening experience, sensorimotor information from the articulators influences speech perception. These results transform theories of speech perception by suggesting that even at the initial stages of development, oral-motor movements influence speech sound discrimination. Moreover, an experimentally induced "impairment" in articulator movement can compromise speech perception performance, raising the question of whether long-term oral-motor impairments may impact perceptual development.
authors.affiliation: School of Audiology and Speech Sciences, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada V6T1Z3; Department of Psychology, University of British Columbia, Vancouver, BC, Canada V6T1Z4 agreuel@audiospeech.ubc.ca.
authors.forename: Alison G
authors.initials: AG
authors.lastname: Bruderer
authors.affiliation: Department of Psychology, University of British Columbia, Vancouver, BC, Canada V6T1Z4.
authors.forename: D Kyle
authors.initials: DK
authors.lastname: Danielson
authors.affiliation: Department of Psychology, University of British Columbia, Vancouver, BC, Canada V6T1Z4.
authors.forename: Padmapriya
authors.initials: P
authors.lastname: Kandhadai
authors.affiliation: Department of Psychology, University of British Columbia, Vancouver, BC, Canada V6T1Z4.
authors.forename: Janet F
authors.initials: JF
authors.lastname: Werker
mesh_terms: D000161:Acoustic Stimulation / Q000295:instrumentation / Q000379:methods; D000704:Analysis of Variance; D001307:Auditory Perception / Q000502:physiology*; D002657:Child Development / Q000502:physiology; D005260:Female; D006801:Humans; D007223:Infant; D007804:Language Development; D008297:Male; D010700:Phonetics; D066191:Sensorimotor Cortex / Q000502:physiology*; D013016:Sound; D013063:Speech Discrimination Tests; D013067:Speech Perception / Q000502:physiology*; D014059:Tongue / Q000000981:diagnostic imaging / Q000502:physiology; D014463:Ultrasonography
keywords: infancy; language acquisition; perception–production