Intersensory processing of faces and voices at 6 months predicts language outcomes at 18, 24, and 36 months of age

Sensitivity to temporal synchrony in audiovisual speech and language development in infants with an elevated likelihood of autism: A developmental review

Detecting temporal synchrony in audiovisual speech in infancy is fundamental for socio-communicative development, especially for language acquisition. Autism is an early-onset and highly heritable neurodevelopmental condition often associated with language difficulties that usually extend to infants with an elevated likelihood of autism. Early susceptibilities in still unclear basic mechanisms may underlie these difficulties. Here, we discuss why sensitivity to temporal synchrony in audiovisual speech should be investigated in infants with an elevated likelihood of autism as a candidate mechanism underlying language difficulties. We then review direct and indirect eye-tracking evidence. Although scarce, some studies suggest that detection of temporal synchrony in audiovisual speech may be reduced in infant siblings (but evidence is mixed); however, this does not seem to account for language difficulties. Instead, a lack of relationship between selective attention to the articulating mouth and language development may be a plausible candidate mechanism. However, longitudinal studies tracking both sensitivity to temporal synchrony and selective attention to talking faces in the first year are needed for further clarification. Our discussion highlights gaps in the literature, future research directions and implications for domain-general approaches to the emergence of autism.

Sensitivity to temporal synchrony and selective attention in audiovisual speech in infants at elevated likelihood for autism: A preliminary longitudinal study

Autism Spectrum Disorder is a highly heritable condition characterized by sociocommunicative difficulties, frequently entailing language atypicalities that extend to infants with a familial history of autism. The developmental mechanisms underlying these difficulties remain unknown. Detecting temporal synchrony between the lip movements and the auditory speech of a talking face and selectively attending to the mouth support typical early language acquisition. This preliminary eye-tracking study investigated whether these two fundamental mechanisms atypically function in infant siblings. We longitudinally tracked the trajectories of infants at elevated and low-likelihood for autism in these two abilities at 4, 8, and 12 months (n = 29). We presented two talking faces (synchronous and asynchronous) while recording infants' gaze to the talker's eyes and mouth. We found that infants detected temporal asynchronies in talking faces at 12 months regardless of group. However, compared to their typically developing peers, infants with an elevated likelihood of autism showed reduced attention to the mouth at the end of the first year and no variations in their interest to this area across time. Our findings provide preliminary evidence on a potentially atypical trajectory of reduced mouth-looking in audiovisual speech during the first year in infant siblings, with potential cascading consequences for language development, thus contributing to domain-general accounts of emerging autism.

Building language learning: Relations between infant attention and social contingency in the first year of life

In Western societies, social contingency, or prompt and meaningful back-and-forth exchanges between infant and caregiver, is a powerful feature of the early language environment. Research suggests that infants with better attentional skills engage in more social contingency during interactions with adults and, in turn, social contingency supports infant attention. This reciprocity is theorized to build infant language skills as the adult capitalizes on and extends the infant's attention during socially contingent interactions. Using data from 104 infants and caregivers, this paper tests reciprocal relations between infant attention and social contingency at 6- and 12-months and the implications for infant vocabulary at 18-months. Infant attentional skills to social (women speaking) and nonsocial (objects dropping) events were assessed, and social contingency was examined during an 8-minute toy play interaction with a caregiver. Child receptive and expressive vocabulary was measured by caregiver-report. Both social and nonsocial attentional skills related to engagement in social contingency during caregiver-infant interaction, though only models that included social attention and social contingency predicted vocabulary. These findings provide empirical evidence for the proposed reciprocal relations between infant attention and social contingency as well as how they relate to later language.

The effects of socioeconomic status on working memory in childhood are partially mediated by intersensory processing of audiovisual events in infancy

Socioeconomic status (SES) is a well-established predictor of individual differences in childhood language and cognitive functioning, including executive functions such as working memory. In infancy, intersensory processing-selectively attending to properties of events that are redundantly specified across the senses at the expense of non-redundant, irrelevant properties-also predicts language development. Our recent research demonstrates that individual differences in intersensory processing in infancy predict a variety of language outcomes in childhood, even after controlling for SES. However, relations among intersensory processing and cognitive outcomes such as working memory have not yet been investigated. Thus, the present study examines relations between intersensory processing in infancy and working memory in early childhood, and the role of SES in this relation. Children (N = 101) received the Multisensory Attention Assessment Protocol at 12-months to assess intersensory processing (face-voice and object-sound matching) and received the WPPSI at 36-months to assess working memory. SES was indexed by maternal education, paternal education, and income. A variety of novel findings emerged. 1) Individual differences in intersensory processing at 12-months predicted working memory at 36-months of age even after controlling for SES. 2) Individual differences in SES predicted intersensory processing at 12-months of age. 3) The well-established relation between SES and working memory was partially mediated by intersensory processing. Children from families of higher-SES have better intersensory processing skills at 12-months and this combination of factors predicts greater working memory two years later at 36-months. Together these findings reveal the role of intersensory processing in cognitive functioning.

Perception of audio-visual synchrony in infants at elevated likelihood of developing autism spectrum disorder

The inability to perceive audio-visual speech as a unified event may contribute to social impairments and language deficits in children with autism spectrum disorder (ASD). In this study, we examined and compared two groups of infants on their sensitivity to audio-visual asynchrony for a social (speaking face) and non-social event (bouncing ball) and assessed the relations between multisensory integration and language production. Infants at elevated likelihood of developing ASD were less sensitive to audio-visual synchrony for the social event than infants without elevated likelihood. Among infants without elevated likelihood, greater sensitivity to audio-visual synchrony for the social event was associated with a larger productive vocabulary.

CONCLUSION

Findings suggest that early deficits in multisensory integration may impair language development among infants with elevated likelihood of developing ASD.

WHAT IS KNOWN

•Perceptual integration of auditory and visual cues within speech is important for language development. •Prior work suggests that children with ASD are less sensitive to the temporal synchrony within audio-visual speech.

WHAT IS NEW

•In this study, infants at elevated likelihood of developing ASD showed a larger temporal binding window for adynamic social event (Speaking Face) than TD infants, suggesting less efficient multisensory integration.