When a child with autism copies the actions of an adult, he or she is likely to omit anything "silly" about what they've just seen. In contrast, typically developing children will go out of their way to repeat each and every element of the behavior even as they may realize that parts of it don't make any sense.
The findings, reported in the Cell Press journal Current Biology on April 8, are the first to show that the social nature of imitation is very important and challenging for children with autism, the researchers say. They also emphasize just how important it is for most children to be like other people.
"The data suggest that children with autism do things efficiently rather than socially, whereas typical children do things socially rather than efficiently," says Antonia Hamilton of the University of Nottingham. "We find that typical children copy everything an adult does, whereas autistic children only do the actions they really need to do."
The researchers made the discovery after testing 31 children with autism spectrum conditions and 30 typically developing children who were matched for verbal mental age. On each of five trials, each child was asked to watch carefully as a demonstrator showed how to retrieve a toy from a box or build a simple object. Importantly, each demonstration included two necessary actions (e.g. unclipping and removing the box lid) and one unnecessary action (e.g. tapping the top of the box twice). The box was then reset behind a screen and handed to the child, who was instructed to "get or make the toy as fast as you can." They were not specifically told to copy the behavior they'd just seen.
Almost all of the children successfully reached the goal of getting or making the toy, but typically developing children were much more likely to include the unnecessary step as they did so, a behavior known as overimitation. Those children copied 43 to 57 percent of the unnecessary actions, compared to 22 percent in the children with autism. That's despite the fact that the children correctly identified the tapping action as "silly," not "sensible."
Hamilton says the researchers now want to know precisely what kind of actions children copy, and how that tendency to copy everything might contribute to human cultural transmission of knowledge. She says that parents and teachers should be aware of the social value in going beyond the successful completion of such tasks.
Current Biology, Marsh et al.: "Children with autism do not overimitate"