Nyström, P., Thorup, E., Bölte, S., Falck-Ytter, T. (2019) Joint attention in infancy and the emergence of autism Biological Psychiatry

In typical infant development, parents and their children jointly contribute to establishing frequent episodes of joint attention, which boost language acquisition and shape social cognition. Here we used novel live eye tracking technology to evaluate the degree to which Autism Spectrum Disorder (ASD) is related to reduced responding to others’ joint attention bids in infancy (RJA) and to a reduced tendency to initiate joint attention episodes (IJA). Because young infants use their gaze for both RJA and IJA, this approach allowed us to quantify these elusive processes early in life. The final sample consisted of 112 infants (54 boys, 58 girls), of which 81 were at familial risk for ASD and 31 were low-risk controls. At follow up (36 months), 22 children in the high risk group were diagnosed with ASD. At 10 months, rates of IJA were lower in infants later diagnosed with ASD than in control groups (effect sizes d= 0.78-0.95), and followed an atypical developmental trajectory from 10 to 18 months (p < .002). RJA distinguished infants based on familial ASD risk, albeit not ASD diagnosis. The differences in IJA could not be explained by overall looking time, social preference, eye movement latencies or number of fixations. This live eye tracking study suggests that during a critical period for the development of social cognition (10-18 months), infants later diagnosed with ASD show marked atypicalities in IJA, but not RJA. The results indicate that IJA is an important target for future prodromal intervention trials.