Dyadic Vocal Contingency in Infants at High Risk for Autism Spectrum Disorder

Identifying the earliest emerging signs of autism spectrum disorder (ASD) is a priority for understanding how the disorder develops and unfolds, as well as for shaping and facilitating the provision of early intervention services. Further, there is a gap in our understanding of the mechanisms underlying these prodromal differences in socio-communicative behaviors. Temporal contingency in dyadic interactions may be one such mechanism. The present study examined contingency of infant vocal responsiveness to adult social partners as a possible mechanism underlying the relationship between early attention impairments and later language abilities and symptom presentation in ASD. The sample included 42 infants in total, with equal numbers across three groups: infants at heightened genetic risk for ASD with later ASD diagnoses (HR-ASD), infants at heightened risk without later ASD diagnoses (HR-neg), and infants with no known family history of ASD (LR). Results indicated that, while contingency did not significantly mediate the relationship between early attention and later outcomes, more impaired attention differentiated the HR groups from the LR group at 6 months. Attention was related to language outcomes at 6 months but not 12 months, possibly highlighting a window during which the HR-neg group becomes distinct from the HR-ASD group. At 12 months, the HR-ASD group demonstrated lower probability of vocalizing in response to adult vocalization as compared to both the HR-neg and LR groups. Contingency probability was also significantly predictive of later ASD diagnosis, such that higher contingency predicted lower likelihood of a positive ASD diagnosis. These findings suggest that targeting contingent responsiveness may offer a key opportunity for pre-diagnostic intervention, particularly for infants at heightened genetic susceptibility for ASD. This research also identifies a potential mechanism through which early risk factors for ASD are exacerbated, leading to cascading socio-communicative challenges.