Visual Illusions help us understand visual processing in autism

Emily Knight, MD, PhD, Assistant Professor of Developmental Behavioral Pediatrics and Neuroscience Jiashu Wang, Undergraduate Research Assistant, Department of Neuroscience

October 5, 2022

AUCD's network of Intellectual and Developmental Disability Research Centers (IDDRCs) consists of 16 Centers. Fifteen Centers currently receive funding from the Eunice Kennedy Shriver National Institute for Child Health and Human Development (NICHD). IDDRCs contribute to the development and implementation of evidence-based practices by evaluating the effectiveness of biological, biochemical, and behavioral interventions; developing assistive technologies; and advancing prenatal diagnosis and newborn screening.

How our brain puts together pieces of an object or visual scene is important in helping us interact with our environments. When we are viewing an object or visual scene our brains use processes that take into account prior experience and contextual information to help anticipate sensory inputs, address ambiguity and fill in the missing information. Children on the autism spectrum differ from typically developing children in many aspects of their visual processing, such that in some ways they may be seeing things in a different way than neurotypical peers. 

In a recent study done in the Frederick J. and Marion A. Schindler Cognitive Neurophysiology Laboratory at the Del Monte Institute for Neuroscience at the University of Rochester, researchers have found that children on the autism spectrum may not fill in missing information to see shapes in the same way as neurotypical children. This may mean that children on the autism spectrum are more likely to see the details of an object rather than putting those details together to see the big picture. 

To study how the brain is doing this, we used a specific type of illusion known as the illusory contour– groups of Pac-Man shaped pictures that when put together create the illusion of a shape in the empty space between them.


Visual illusions, like the illusory contour, are useful tools because they trick our brain. These illusions help neuroscientists understand more about how specific pathways in the brain process what we see are seeing. They can give us a window into how brains with autism understand the world they see around them differently than neurotypical brains.

For this research, we invited 60 children with and without autism (7-17 years old) into the lab. The children looked at a red dot in the middle of a computer screen and were asked to press a button when the dot turned green. Around the dot, other pictures would appear on the screen and sometimes form the illusion of a shape. The children were told to pay attention to the dot and ignore the other pictures. Using EEG, the team studied the automatic response of the brain when the children saw the illusions.

The EEG revealed that children with autism didn’t seem to be automatically processing the illusory shapes as well as children without autism. This indicated that the children with autism might not be able to do the same predicting and filling-in of missing visual information as their peers. The next steps are to try to understand whether this may relate to the atypical visual sensory behaviors we see in some children on the autism spectrum or whether this may contribute to difficulty in interpreting visual social cues. For example, you can read more about another study of how children with autism see body language here. We also need to continue this work with people on the autism spectrum who have a wider range of verbal and cognitive abilities and with other diagnoses such as ADHD. Continuing to use these neuroscientific tools, we are hoping to better understand how people with autism see the world, so that we can find new ways to support children and adults on the autism spectrum.


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