A study at the Albert Einstein College of Medicine in New York sheds new light on why people with autism tend to avoid making eye contact. Lack of eye contact was thought to be a social deficit, but it could instead be the result of brain differences in processing visual stimuli.
The study included 22 children with autism and 31 typically developing children. The children watched a screen with a checkerboard pattern, while researchers monitored their brain activity using electrodes. Results showed that children with autism showed more activity in the brain cortex when the image was on their periphery, while the opposite was true for the children who did not have the disorder.
This suggests that children with autism have differences in how their visual cortex is mapped, which could explain why they are less likely to make eye contact. It also offers an explanation for those children who tend to look at objects out of the corner of their eyes – their brains process the visual information better that way.
One theory is that motor deficits may affect eye movements early in life, which could prevent the cortex from developing the connections inherent in children without the disorder. This means that the autistic brain is not damaged, it simply failed to develop fully due to early motor difficulties.
When babies don’t make eye contact, parents and caregivers may become less responsive, effectively cutting off the feedback loop that helps babies learn the basics of back and forth social interaction.
Another study at the University of Wisconsin Madison found that the amygdala of children with autism lit up when the subject looked directly at another person’s face, even if the face was not threatening. The amygdala is the part of the brain responsible for flight-or-fight, and is associated with negative emotion.The subjects were placed in an MRI machine and showed pictures of faces, some neutral and some threatening. The children pressed a button to indicate whether the face was blank or expressive. The subject’s eye movements were also tracked to determine which parts of the face the subjects were looking at, and for how long.
This study disproved a previous theory that a malfunction in the fusiform area of the brain was responsible for social deficits in autism. The fusiform area was found to be normal, but under-developed, because the extreme response of the amygdala led the children to turn away from other people’s faces.
These studies have implications for future treatments. Evidence is showing that the major brain differences in children with autism are due to under connectivity rather that from physical differences in the brain itself. The cortex and the fusiform are functioning correctly, they simply aren’t getting the needed stimulation to foster social growth, due to possible visual motor difficulties, or to an over-responsive amygdala. This means that therapeutic approaches designed to compensate for these difficulties early in life may lead to a decrease in symptoms.