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 sociocommunicativedevelopment, especially for language acquisition. Autism is an early-onset andhighly heritable neurodevelopmental condition often associated with language difficulties thatusually extend to infants with an elevated likelihood of autism. Early susceptibilities in still unclearbasic mechanisms may underlie these difficulties. Here, we discuss why sensitivity totemporal synchrony in audiovisual speech should be investigated in infants with an elevatedlikelihood of autism as a candidate mechanism underlying language difficulties. We then reviewdirect and indirect eye-tracking evidence. Although scarce, some studies suggest that detection oftemporal synchrony in audiovisual speech may be reduced in infant siblings (but evidence ismixed); however, this does not seem to account for language difficulties. Instead, a lack ofrelationship between selective attention to the articulating mouth and language developmentmay be a plausible candidate mechanism. However, longitudinal studies tracking both sensitivityto temporal synchrony and selective attention to talking faces in the first year are needed forfurther clarification. Our discussion highlights gaps in the literature, future research directionsand implications for domain-general approaches to the emergence of autism.