Social visual engagement - the way in which babies collect information by looking before they can reach, crawl or walk - is heritable and impaired in children with autism, suggests a new study published online in Nature this week. This research supports the notion that social visual engagement is a critical aspect of infant development in the seeking and understanding of social behaviour, not only for children with autism but also for the broader population.

Warren Jones and colleagues conducted a series of eye-tracking experiments that assessed variation in viewing social scenes - including levels of attention to faces and face-like stimuli, and the timing, direction, and targeting of individual eye movements - in 338 toddlers, including 166 identical and fraternal twins, 88 non-twins diagnosed with autism spectrum disorder, and 84 singleton controls. The authors found that identical twin pairs responded similarly (with a high concordance of 91%) and fraternal twin pairs less so (with a low concordance of 35%), indicating a strong genetic component to such behaviours. Moreover, the measures that are most highly heritable, including preferential attention to eye and mouth regions of the face, are also those that are differentially diminished in children with autism.

The authors conclude that these findings lend insight into the way a child’s genetic characteristics allow him or her to interact with his or her environment. While the authors acknowledge that similar concepts have been explored in other studies contrasting the experiential development of children with autism and their typically developing peers, they say that this is the first time, to their knowledge, that a directly traceable genetic influence has been demonstrated.