Sensorimotor influences on speech perception in pre-babbling infants: Replication and extension of Bruderer et al. (2015)

• Published in: Psychonomic bulletin & review 2019-08, Vol.26 (4), p.1388-1399
• Main Authors: Choi, Dawoon, Bruderer, Alison G., Werker, Janet F.
• Format: Article
• Language: English
• Subjects: Babies; Behavioral Science and Psychology; Brief Report; Cognitive Psychology; Discrimination; Experiments; Feedback, Sensory - physiology; Female; Humans; Infant; Infant vocalization; Infants; Influence; Language; Language Development; Language processing; Lips; Male; Movement - physiology; Perception/production relationship; Phonetics; Psychology; Researchers; Speech; Speech perception; Speech Perception - physiology; Studies; Tongue; Tongue - physiology
• ISSN: 1069-9384; 1531-5320
• DOI: 10.3758/s13423-019-01601-0

The relationship between speech perception and production is central to understanding language processing, yet remains under debate, particularly in early development. Recent research suggests that in infants aged 6 months, when the native phonological system is still being established, sensorimotor information from the articulators influences speech perception: The placement of a teething toy restricting tongue-tip movements interfered with infants’ discrimination of a non-native contrast, /Da/-/da/, that involves tongue-tip movement. This effect was selective: A different teething toy that prevented lip closure but not tongue-tip movement did not disrupt discrimination. We conducted two sets of studies to replicate and extend these findings. Experiments 1 and 2 replicated the study by Bruderer et al. (Proceedings of the National Academy of Sciences of the United States of America, 112 (44), 13531-13536, 2015 ), but with synthesized auditory stimuli. Infants discriminated the non-native contrast (dental /da/ - retroflex /Da/) (Experiment 1 ), but showed no evidence of discrimination when the tongue-tip movement was prevented with a teething toy (Experiment 2 ). Experiments 3 and 4 extended this work to a native phonetic contrast (bilabial /ba/ - dental /da/). Infants discriminated the distinction with no teething toy present (Experiment 3 ), but when they were given a teething toy that interfered only with lip closure, a movement involved in the production of /ba/, discrimination was disrupted (Experiment 4 ). Importantly, this was the same teething toy that did not interfere with discrimination of /da/-/Da/ in Bruderer et al. ( 2015 ). These findings reveal specificity in the relation between sensorimotor and perceptual processes in pre-babbling infants, and show generalizability to a second phonetic contrast.