Effect of infant bilingualism on audiovisual integration in a McGurk task.

Infants growing up in an environment where more than one language is spoken tend to follow the early milestones of early language development. This is an impressive achievement given that they are learning two languages while receiving reduced exposure to each of these languages compared with monolingual infants. This increased variability in their linguistic environment may lead to adjustments in the way bilingual infants process visual and auditory speech. This study aimed to clarify the influence of infant bilingualism on the development of audiovisual speech integration. Using eye tracking and a McGurk paradigm, we studied face scanning patterns when 7- to 10-month-old infants were viewing articulation of audiovisually congruent and incongruent syllables. We found that monolingual infants decreased their attention to the mouth and increased their attention to the eyes of speaking faces when presented with incongruent articulation, typically leading to the McGurk illusion during adulthood. In bilingual infants, no differences in face scanning patterns were observed between audiovisually congruent and incongruent articulation, suggesting that the increased variability in their speech experience may lead to more tolerance to articulatory inconsistencies. These results suggest that the development of audiovisual speech perception is influenced by infants' language environment.

Early differences in auditory processing relate to Autism Spectrum Disorder traits in infants with Neurofibromatosis Type I.

BACKGROUND: Sensory modulation difficulties are common in children with conditions such as Autism Spectrum Disorder (ASD) and could contribute to other social and non-social symptoms. Positing a causal role for sensory processing differences requires observing atypical sensory reactivity prior to the emergence of other symptoms, which can be achieved through prospective studies. METHODS: In this longitudinal study, we examined auditory repetition suppression and change detection at 5 and 10 months in infants with and without Neurofibromatosis Type 1 (NF1), a condition associated with higher likelihood of developing ASD. RESULTS: In typically developing infants, suppression to vowel repetition and enhanced responses to vowel/pitch change decreased with age over posterior regions, becoming more frontally specific; age-related change was diminished in the NF1 group. Whilst both groups detected changes in vowel and pitch, the NF1 group were largely slower to show a differentiated neural response. Auditory responses did not relate to later language, but were related to later ASD traits. CONCLUSIONS: These findings represent the first demonstration of atypical brain responses to sounds in infants with NF1 and suggest they may relate to the likelihood of later ASD.

Impact of Language Experience on Attention to Faces in Infancy: Evidence From Unimodal and Bimodal Bilingual Infants.

Faces capture and maintain infants' attention more than other visual stimuli. The present study addresses the impact of early language experience on attention to faces in infancy. It was hypothesized that infants learning two spoken languages (unimodal bilinguals) and hearing infants of Deaf mothers learning British Sign Language and spoken English (bimodal bilinguals) would show enhanced attention to faces compared to monolinguals. The comparison between unimodal and bimodal bilinguals allowed differentiation of the effects of learning two languages, from the effects of increased visual communication in hearing infants of Deaf mothers. Data are presented for two independent samples of infants: Sample 1 included 49 infants between 7 and 10 months (26 monolinguals and 23 unimodal bilinguals), and Sample 2 included 87 infants between 4 and 8 months (32 monolinguals, 25 unimodal bilinguals, and 30 bimodal bilingual infants with a Deaf mother). Eye-tracking was used to analyze infants' visual scanning of complex arrays including a face and four other stimulus categories. Infants from 4 to 10 months (all groups combined) directed their attention to faces faster than to non-face stimuli (i.e., attention capture), directed more fixations to, and looked longer at faces than non-face stimuli (i.e., attention maintenance). Unimodal bilinguals demonstrated increased attention capture and attention maintenance by faces compared to monolinguals. Contrary to predictions, bimodal bilinguals did not differ from monolinguals in attention capture and maintenance by face stimuli. These results are discussed in relation to the language experience of each group and the close association between face processing and language development in social communication.