A visual advantage in autism

One of the miracles of our existence is the way that we develop. Infants are born relatively helpless; unable to talk, walk, or feed themselves, and without adult care do not survive. However, within a few short years they acquire a vast range of physical, cognitive, linguistic, emotional, and social skills.

Of course, every child learns these skills at their own rate; some talk early but sit in one place, whereas others keep their thoughts to themselves but start walking well before their first birthday. Developmental experts plot these ages to work out “norms” – that is, an average pattern of development across children. No single child will stick to this pattern across all the skills that they acquire, but it provides a way of assessing where the child is ahead of the pack and where they may be behind.

Although all children vary to some extent from the “norms,” some do so in ways that seem quite different from those of typical kids. Children who get past their second birthday without talking, for example, are potentially on a different developmental trajectory from most of their peers. These kids may be assessed as having a “developmental disorder”. Such a diagnosis is an invitation for the child to be given extra support for skills that are slow to develop without systematic attention.

One of the most common developmental disorders is autism. While estimates of prevalence vary, the US Centers for Disease Control currently estimate that 1 in 68 kids in the US are diagnosed within the Autism Spectrum Disorder (ASD). Most schools in developed countries like New Zealand will have systems in place to work with kids who have a diagnosis of autism, since it is relatively common. Importantly too, there are plenty of kids who have some features of ASD but not strongly enough to warrant a formal diagnosis; however, they also need additional support for at least some of their learning activities.

ASD is fundamentally a social disorder; kids with autism typically show a reduced social focus, impaired language and communication, and they may engage in repetitive behaviour. But of course we have all heard of stories of autistic savants too; people with autism who are much better than normal at memorizing information, performing calculations, or playing a musical instrument. Clearly it is a complex disorder, so accounting for exactly how kids with autism differ from their typically developing peers is a difficult job.

One way we can do this is to try to isolate relatively fundamental psychological processes. One such study, from an international team of researchers that includes the Head of Optometry and Vision Science at the University of Auckland, Prof Steven Dakin, is being published this week in the prestigious Journal of Neuroscience. Steven and his colleagues were interested in comparing kids with ASD and their typically developing peers on their ability to see the overall movement of a set of dots where each dot is moving somewhat differently to the others. To imagine the task, think about a large school of fish. At any moment, you can say that the school is moving in a particular direction. However, if you look at the individual fish, each one is probably moving somewhat differently to all the rest. Our judgment of the movement of the whole school comes from our ability to average all the individual movements together. If we can only focus on individual fish, we will never see the overall movement of the school.

Some descriptions of kids with autism note their attention to parts of objects, rather than the whole thing – for example, they may obsessively spin the wheels of the toy car rather than pretend to drive it somewhere. As such, you might expect that they would find the group movement judgments very challenging. The fascinating result found by Steven and his research team was the opposite – the children with ASD performed BETTER than typically developing children at this task. This result suggests that the kids with autism were better able to integrate all the individual movements together, and extract the average movement from the disparate elements.

What might be the practical outcome of this enhanced ability to integrate visual elements together? One is tempted to think of a story of how it might provide an opportunity for savant skills to develop, such as an enhanced musical ability. We must be careful, however, not to equate better performance on a psychophysical task with superior abilities in complex domains like music and mathematics. Rather, this may be an indicator of maladaptive processing. The authors speculate that such powerful integration might lead to the sensory overload that so many kids with autism subjectively experience.

In any event, Steven and his colleagues show the advantage to testing behaviour of developmentally delayed children using sophisticated techniques that have been carefully implemented. More work like this will give us a better insight into the world of autism: a world that is difficult for its inhabitants to describe to the rest of us.

For more information on the research programme of Prof Steven Dakin, click here: https://unidirectory.auckland.ac.nz/people/s-dakin

For the media release on this research article, click here:

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