Across different studies, impairments in joint attention (JA) behaviours characterise young children with autism (Elsabbagh & Johnson, 2007). Charman (2003) notes that the majority of studies based on retrospective parental report show that JA difficulties are likely to be the best ‘discriminators’ of autism in infants between 12 and 18 months. Whilst JA impairments in autism have been widely studied, little is known about the development of the precursor abilities of following gaze. Typically developing human infants are highly sensitive to eye-gaze cues and consistently follow someone’s gaze in the latter half of the first year of life. In order to study the early development of gaze following we investigated this behaviour in infants at risk for autism spectrum disorder (ASD).
Objectives:
To explore the early development of gaze following in the broader autism phenotype (BAP) our study examined the direction of ‘first look’ and the amount of ‘looking time’ to the gazed-at object. Our participants were a longitudinal sample of infants aged 7 and 13 months at high risk for autism (due to having an older sibling with autism) and low-risk controls. We aimed to establish whether any early differences in gaze following behaviour in at-risk infants might contribute to subsequent social and communication difficulties at 24 months.
Methods:
Participants were 35 infants at high risk for ASD and 38 low-risk controls recruited through the British Autism Study of Infant Siblings (BASIS).
We employed Tobii eye-tracking techniques to record gaze behaviour. Infants were shown 12 short videos of a female model turning to look at one of two objects. We compared high-risk and low-risk groups and also ‘sibs-low ADOS’ and ‘sibs-high ADOS’ split on the basis of the Autism Diagnostic Observation Schedule (ADOS; Lord et al., 2000), which was administered at 24 months.
Results:
No differences between the at-risk and control group were found, either in terms of gaze following or subsequent attention to the gazed-at object. Further, at both visits sibs-low ADOS and sibs-high ADOS followed the model’s gaze and performance improved over time. However despite orienting correctly, by the second visit at-risk infants who went on to show social communication difficulties (sibs-high ADOS) spent less time looking to the correct object.
Conclusions:
This study provides evidence that the basic orienting mechanism for early gaze following behaviour is intact in at-risk infants. However, the emergence of reduced looking time to the correct object in those who later show social communication difficulties, suggests that having decoded gaze direction these children may not use it to learn about the gazed at object. This has implications in terms of understanding the nature of autistic social impairments. It may be that it is not gaze following per se but rather understanding its function that is problematic in this population.
* The BASIS Team in alphabetical order: S. Baron-Cohen, P. Bolton, S. Chandler, J. Fernandes, H. Garwood, K. Hudry, L. Tucker, A. Volein.
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