Thursday, June 7, 2012

Using magic (tricks) to study autism

To say that the brain is a complex organ is a tremendous understatement.  It is so complex, that it is often hard to believe that it works so well for most people.  At times, though, something goes wrong.  We can get a lot of insight into the way that brains function by studying both normal brains and abnormal ones.
A fascinating example of this work is presented in a paper by Gustav Kuhn, Anastasia Kourkoulou and Susan Leekam in the October, 2010 issue of Psychological Science.  These researchers compared normal people with a group of people who have autism spectrum disorder (abbreviated ASD).  These patients had  a high-functioning form of autism.  Some of these people used to be diagnosed with Asperger’s syndrome, which is no longer an official diagnosis. 
The researchers looked at how normal and ASD people interpret a magic trick.  They started with an interesting hypothesis that the ASD people might actually be less likely to see the trick as magic, because they often notice fine details in people’s behavior. 
The trick they used is called the vanishing ball illusion.  In this trick, a magician throws a ball in the air twice.  Each time, he watches the ball as it goes up and down.  On the third throw, he palms the ball and makes a throwing motion.  At the same time, he looks up in the air again.  Many people claim to see a ball that then disappears. 
In this study, people were told that they were going to see a magic trick, and they had to figure out how it was done.  They watched a video of the trick, and while they were watching it, their eyes were being tracked.
Contrary to the researchers’ expectation, the ASD people were actually more likely to fall for the illusion than the normal people.  The eye movement data were quite interesting in helping to understand why.  The normal individuals did a good job of tracking the ball on the first two throws, and on the third throw, they looked both at the magician’s face and the path of the ball.  As a result, the normal people tended to see that the ball was never thrown on the third toss.
The ASD people had trouble tracking the ball on each of the first two throws, and so they tended to look at the magician’s face to see where the ball went.  On the third throw, they looked at the magician’s face again, and so they used his gaze to decide where the ball went on the last toss.  They were more likely than the normal people to claim to see the ball thrown on the third toss, because they were generally focused on the magician’s face rather than the ball.
It may seem surprising that the ASD people focused on the magician’s face, because many studies of autism and related disorders has focused on difficulties that people with autism have dealing with social information.  However, the evidence that people with autism have difficulty with all social information is mixed.
The findings of this study suggest that people with ASD may have difficulty switching their attention from one thing to another in a situation.  In a complex situation like this, a person has to shift their attention between the magician’s face, his hands, and the ball. 
Think about how difficult it would be to figure out what is going on the world if you have even a small difficulty in shifting your attention from one thing to another.  You would always be a little off in your interpretation of what is going on around you. 
Obviously, ASD is a complex disorder, and it will take many studies to pin down exactly what is going on.  But, these results demonstrate that difficulties with basic components of cognition can have a huge impact on a person’s ability to comprehend the world.