Are people with autism susceptible to magical illusions? There are a number of reasons to suspect that they might not be.
Firstly, magicians rely on misdirection. They'll use eye gaze and gesture to make sure the audience is looking one way, while they're secretly switching the cards or sneaking an elephant into a hat (or whatever it is they do). People with autism, it's argued, are less sensitive to these kinds of social cues, so perhaps they're not as easily misdirected.
Second, as mentioned in a previous post, there are a number of studies suggesting that people with autism are less susceptible to visual illusions. They see what's there in front of them rather than what they're supposed to see. Another reason to think that the magician might not be able to trick them as easily as a non-autistic person.
Gustav Kuhn and colleagues set off to test this prediction by getting participants to watch a short video clip of the vanishing ball illusion. In the clip, a magician threw a ball up in the air twice. He then pretended to throw the ball a third time but actually kept hold of it. Non-autistic people tend to report that they have actually seen the ball thrown a third time before disappearing into thin air. The illusion is particularly strong if the magician looks to where the ball is expected to be.
|Keep your eye on the ball...|
Surprisingly, Kuhn et al. found that adults with autism were, if anything, more susceptible to the illusion than non-autistic adults. They would report having last seen the ball at a much higher location. And when asked what had happened to the ball, they were more likely to give an explanation that involved the ball leaving the hand.
Kuhn et al also report some eyetracking data, which provides some clues. It turns out that the participants with autism spent less time fixating on the ball. They also tended not to follow the ball to the top of its trajectory, which fits in well with other studies showing problems on smooth pursuit tasks, in which participants have to follow the trajectory of a moving object.
The authors conclude that the adults with autism were misdirected by the magician's social cues, challenging the idea that they have social attention difficulties. This is quite a bold conclusion to reach based on a single 6-second video clip, particularly as there was no comparison between clips with and without social cues. And the eye-tracking data seems to suggest an alternative explanation - that the autistic adults were tricked because they simply were not following the ball closely enough.
Nevertheless, the study highlights the potential of using magic tricks as a means of investigating the social and non-social attention skills of people with autism. It would certainly be interesting to see how they fare on other magical illusions. At this stage, I'm not making any predictions.
Kuhn G, Kourkoulou A, & Leekam SR (2010). How Magic Changes Our Expectations About Autism. Psychological science : a journal of the American Psychological Society / APS PMID: 20855904