Social and Attention Factors During Infancy and the Later Emergence of Autism Characteristics

Background: Characteristic features of autism include atypical social perception and visual attention.  Debate has focused on whether the later emergence of atypical social skills is a consequence of attention problems early in life, or, conversely, whether early social deficits have knock-on consequences for the later development of attention skills.  We investigated this question based on evidence from infants at familial risk for a later diagnosis of autism by virtue of being younger siblings of children with a diagnosis.

Objectives: We previously reported that around 9-10 months, at-risk siblings differ as a group from controls with no family history of autism, both in social perception, measured using Event Related Potentials (ERPs; Elsabbagh et al., 2009) and inhibitory control (Holmboe et al., 2010). We present data from an ongoing longitudinal research program suggesting clear associations between some of these infant measures and autism-related characteristics at 3 years.  

Methods: Participants were from the British Autism Study of Infant Siblings (BASIS). Around 9-10 months of age, ERPs were recorded while the infants viewed static images of direct or averted gaze. The same infants also completed an inhibitory control task: the “Freeze Frame task”. The latter measured attentional flexibility and regulation of looking behaviour in response to changes in the visual environment. Specifically, the task examined whether the value of a centrally presented fixation target modulates automatic orienting responses to briefly presented peripheral distractors. At three years of age, the same infants were followed up using a number of measures including the Autism Diagnostic Observation Schedule (ADOS).

Results: In the group of infant at-risk, the N290 and P400 ERP response to static faces displaying direct or averted gaze was most associated with emerging difficulties in the social domain at three years. Moreover, differential P400 response to direct relative to averted gaze displayed on faces was associated with later emerging non-social characteristics. Results from the Freeze-Frame task indicated that at-risk infants’ propensity to be engaged by a repetitive non-social stimulus predicted later social functioning. The best predictor of later autism-related social characteristics was the overall rate of looking to the distractors in the boring trials (suggesting an increased preference for the central ‘boring’ stimulus), not the initial response to the two trial types or changes across the session.

Conclusions: Response characteristics in a social eye gaze task and a non-social inhibitory control task were both associated with later emerging social and non-social characteristics of autism, suggesting some interdependence of social and non-social circuits early in development. We discuss the findings in terms of the emergent nature of autism as a result of complex developmental interactions among brain networks.

*The BASIS team: Bedford, R., Chandler, S., Clifford, S., Fernandes, J., Garwood, H., Leonard, H., Tucker, L., and Volein, A.