Matching phonetic information in lips and voice is robust in 4.5-month-oldinfants

Past research (Kuhl & Meltzoff, 1982, 1984) shows that 4.5-month-old infant s can match phonetic information in the lips and voice. These studies used female faces surrounded by black cloth to occlude possible distractions. Th e present studies were conducted to replicate and extend past research by e xamining how robust the ability to match phonetic information in lips and v oice is at 4.5-months of age. If speech is represented intermodally in youn g infants then they should show evidence of matching phonetic information w hen presented with faces shown from the shoulders up, revealing hair and so me clothing, and with male as well as female models. In each of two studies , 32 infants were seated in front of two side-by-side video monitors displa ying filmed images of a female face (Study 1) or a male face (Study 2). The face on each side articulated a different vowel sound (/i/ or /a/) in sync hrony. The sound track was played through a central speaker and corresponde d to one of the two vowels but was synchronous with both. Infants spent app roximately equal amounts of time looking and smiling at both the female and the male faces (p > .05). However, infants looked longer at the face that matched the heard vowel for both female and male stimuli (p < .01). Also, i nfants showed articulatory imitation in response to the matching face/voice stimuli (p < .05). The finding that bimodal phonetic matching is replicate d with full, naturalistic heads and with male stimuli supports the hypothes is that infants are able to link phonetic information presented in the lips and voice. This supports an integrated, multi-modal representation of arti culatory and acoustic phonetic information at 4.5-months of age.