ADVERTISEMENT

Eyes: A New Window on Mental Disorders

Clues about autism, Williams syndrome and the social brain come from tracking eye movements
tracking eye movements gives clues about autism and Williams syndrome



istockphoto

Humans are social animals. In recent years, psychologists and cognitive neuroscientists have revealed the distinct parts of our brain that allow us to interact, collaborate and communicate with each other. One important way of studying the “social brain” is to look at what happens in the brain during neuro-developmental disorders associated with atypical social abilities.  Two such disorders are autism and Williams syndrome, which is a rare genetic disorder. The exciting new study by the psychologist Deborah Riby and Peter Hancock at Newcastle University uses cutting edge methods in eye tracking to investigate the unusual social preferences and behaviors in people with Williams syndrome and autism.

Unusual Social Brains
When studied in conjunction, Williams syndrome and autism provide a set of interesting and informative contrasts. Individuals with autism tend to be socially withdrawn, lack communication skills and find it difficult to understand what others are feeling or thinking. People with Williams syndrome, in contrast, are often hyper-sociable, have good language skills, and are good at understanding certain social cues, such as facial expressions. For this reason, Williams syndrome is sometimes characterized as being “at the opposite end of the [social] spectrum” as autism. People with autism are generally less socially responsive to others, whereas those with Williams syndrome typically have an inability to inhibit social responses.The question, of course, is, What changes in the brain cause such radically divergent social characteristics? By studying these disorders, scientists can learn a lot about human social cognition.

Tracking the Eyes
Enter eye tracking. Eye tracking is the process of measuring the point of gaze, or where a person is looking. Although eye tracking has been used in earlier studies of social attention in people with autism, Riby and Hancock’s study is the first to use eye tracking to study gaze behaviors in people with Williams syndrome. The beauty of eye tracking is that it allows scientists to monitor a person’s attentional focus or preference without the need for them to express what they are doing or even to understand it. This technology therefore affords a new window into the social world of other people. It’s the closest we can get to seeing the world from someone else’s eyes.

Previous work has shown that people with autism pay less attention to socially relevant parts of scenes. For example, a person with autism who is viewing a movie of people in a room will spend a relatively large amount of time looking at non-social objects—such as chairs—and is more likely to look at the mouths or bodies of the characters than their eyes. Riby and Hancock expand on these experimental paradigms by asking participants to view good quality color photographs of a range of different social situations. For example, they had subjects with autism and Williams syndrome look at pictures of a family sharing a meal, a group of teenagers chatting, and a bride and groom on their wedding day. While viewing the photographs, participants’ eye movements were monitored and recorded using a state-of-the-art eye tracker.

Results of the Riby and Hancock study showed that participants with autism and Williams syndrome both exhibited eye movements that significantly differed from the norm. As expected, people with autism spent less time viewing faces. In contrast, those with Williams syndrome spent significantly more time peering at faces than is typical, and they paid particular attention to the eyes. Eyes are important in allowing us to understand other peoples’ mental and emotional states. Riby and Hancock suggest that a lack of attention to eyes in autism, and a contrasting abundance of attention in Williams syndrome, may help explain why people with Williams syndrome tend to be so much better than those with autism in understanding gaze cues and expressions.

Looking to the future
Riby and Hancock point out that the underlying cause of the hyper-sociability of Williams syndrome is not yet known. Why do people with Williams syndrome spend so much time looking at eyes? It could be that people with Williams syndrome find it harder to control their gaze behavior and hence cannot inhibit excessive staring. Alternatively, they might take longer to process and understand the information they are accessing from the eyes. In addition, the authors point to recent work showing deficits in executive function and working memory tasks in Williams syndrome highlighting the possibility of attentional control problems in such patients. This discovery suggests the possibility that people with Williams syndrome find it difficult to disengage their attention from faces. Because attention shifting deficits have also been reported for autism, Riby and Hancock propose that the relationship between the prefrontal cortex (involved in inhibiting behavior) and the amygdala (involved in emotion processing) may be crucial in both of these neuro-developmental disorders. Future work will, I hope, shed light on the neural underpinnings of these disorders and allow us to better understand why humans are such social animals.

 

Are you a scientist? Have you recently read a peer-reviewed paper that you want to write about? Then contact Mind Matters editor Jonah Lehrer, the science writer behind the blog The Frontal Cortex and the book Proust Was a Neuroscientist.

Rights & Permissions
Share this Article:

Comments

You must sign in or register as a ScientificAmerican.com member to submit a comment.
Scientific American Back To School

Back to School Sale!

12 Digital Issues + 4 Years of Archive Access just $19.99

Order Now >

X

Email this Article

X