Researchers at the UC Davis M.I.N.D. Institute used high-technology eye-tracking headgear and software that measures with precision the point at which a child is looking when learning a task.
They also used an actor to demonstrate a task on a computer screen.
"We found that the children with autism focused on the demonstrator's action and looked at the demonstrator's face much less often than did typically developing children," said Giacomo Vivanti, a postdoctoral researcher at the M.I.N.D. Institute and the study's lead author.
He added: "The typically developing children may be looking at the demonstrator's face to check for information on what to do or how to respond appropriately, information that the children with autism are less inclined to seek. This is an important finding, because children with autism have difficulty learning from others.
This might be one key to why that is so.
M.I.N.D. Institute researcher and senior study author Sally J. Rogers, said that imitation plays an important role in how children learn, as well as in how people interact socially.
She added: "This is a trait we see as early as we can diagnose autism, and it's one of the traits that is present even in mildly impaired adults."
Impaired imitation leads to additional impairments in sharing emotions, pretend play, pragmatic communication and understanding the emotional states of others.
"We now understand more about how this imitation deficit might be working and, after more study, we may actually be able to address it in a way that helps children with autism develop a more natural set of behaviours," said Rogers.
For the study, the researchers compared 18 children between the age group of 8 to 15 with high-functioning autism with a group of 13 typically developing children.
While wearing special eye-tracking headgear, the children were shown video clips that ranged from seven to 19 seconds in length. After viewing each clip, the children performed the demonstrated action.
The study supported previous research that shows that children with autism have difficulty imitating tasks when compared to normally developing children. It also showed that children with autism paid just as much attention to the action being performed as the other children in the study, ruling out previous hypotheses about poor attention to the task.
"This finding is particularly important. Now we can rule out this variable. We know these children are looking at the task," said Rogers.
It was also found that successful performance of a task by children with autism increases with the amount of time they study it but is not correlated with their basic motor skills, ruling out the possibility that it is a lack of motor ability causing the imitation effect.
And finally, the study showed that both groups of children shifted their attention from the action to the demonstrator's face, but the children with autism did this much less often.
Rogers said that the finding suggests that imitation is not just about repeating an action, but understanding the reason for the action.
"That information is conveyed in our faces," she explained.
Now, researchers are hoping to one day develop studies aimed at determining whether or not face-looking is an important part of the imitation process.
"It could be that if people with autism could be better at reading emotion they might naturally start to imitate their models the way like other people do. If it's about how people understand the information in a face, then it gives you a target for intervention," said Rogers.
The study will be published in the Journal of Experimental Child Psychology.