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.