Abstract
Hallmark characteristics of autism include atypical eye contact and visual attention to faces (Dawson et al., 2005). Children with autism spectrum disorder (ASD) use facial information differently than children without ASD (Wolf et al., 2008). Less is known about 1) whether such atypicalities emerge in early infancy, 2) how they develop over the first year, and 3) whether they are related to later ASD development. In this longitudinal eye-tracking study we tested a cohort of 78 infants (infant sibling group, n = 35; control group, n = 43) and measured their visual attention to faces in five tasks, including face preference and eyes vs. mouth when they were 3 month, 6 month, 9 month and 12 month of age. Development of ASD was tested using the Autism Diagnostic Observation Schedule (ADOS; Lord et al. 2000) when the participants reached their second, third, fourth and seventh birthday. Mixed ANOVA analyses revealed that there is an increase of face preference with age in infancy, F(3, 198)= 9.14, p< .001, ηp2= 0.12; male infants showed greater face preference than female infants, F(1, 66)= 4.32, p=.042, ηp2= 0.06. Infant sibling group and control group did not differ on the face preference task, nor the risk group interacts with age, or sex, ps > .330. All effects on other tasks were not significant, ps > .296. A multilevel model with age and autism classification (ASD, Autism Spectrum, No ASD) as fixed effect, and age as a random slope also confirmed a nonsignificant interaction between age and the ADOS-based autism classification, Wald χ2(1) = 0.684, p = 0.408. These results together highlight a different individual developmental trajectory of face preference with age in both infants with ASD and without ASD, but the group differences in face preference may not emerge in infancy.