To transform reality into a mental landscape that occupies our minds, our brain performs a multitude of operations. Some are shortcuts; assumptions that become apparent the moment we try to make sense of the conflict presented in an optical illusion.
For people with autism, these shortcuts and mental operations might work a little differently, subtly influencing how the brain constructs a picture of everyday life.
With this in mind, scientists have turned to optical illusions to better understand neurodivergence.
A study of brain activity in 60 children, including 29 diagnosed with autism spectrum disorder (ASD), suggests that differences in how individuals process illusory forms may reveal how autism affects specific processing pathways in the brain.
The research used a classic style of illusion popularized by Italian psychologist Gaetano Kanizsa, which typically involves lines or simple shapes, such as circles, with sections removed. Arranged in a certain way, the empty spaces line up to describe a second shape in their negative space.
To really “see” the different shapes, higher processing operations in different areas of the brain combine stimuli, transforming a simple pattern of dark and light into a complete image.
Depending on the information that is recruited, the stimuli can be interpreted as one form or the other, but not both at the same time.
The whole process is highly dependent on neurons sharing information rapidly, from the parts of the brain that determine perception to the parts that receive and package visual data, and vice versa.
Autism is defined as a neurological “spectrum disorder” because its traits are extremely diverse, with each person showing different abilities, strengths and challenges.
Generally, however, research has shown that many people with ASD process sensory information, such as sound and sight, in ways that are not neurotypical.
An optical illusion is a good way to explore this neurodivergence.
A 2018 study, for example, found that some people with ASD have trouble switching between seeing a moving object and seeing colors. In a general sense, it appeared that their brains zoomed in on details and overlooked the bigger picture.
In the current study, a similar trend was noticed. When children were seated in a chair with an EEG strapped to their scalp, they were asked to focus on a central dot on a gray background on a screen in front of them, and press a button when the dot turned red at the Green light.
The screen also featured four outline images, either randomly placed or lined up so that the negative space between them outlined a shape.
Asking them to focus on the dot rather than the negative spaces ensured that the participants were “passively” observing the illusion in front of them and not actively trying to “solve” it.
Based on their brain activity, children between the ages of 7 and 17, who had been diagnosed with ASD, demonstrated a delay in processing the Kanizsa delusion.
This doesn’t necessarily mean the participants couldn’t discern the shape formed by the outline images, but it does suggest that their brains processed the illusion in a way that isn’t automatic.
“When we view an object or image, our brain uses processes that take into account our experience and contextual information to help anticipate sensory input, resolve ambiguity, and fill in missing information,” says neuroscientist Emily Knight of the University of Rochester.
“This tells us that these children may not be able to predict and fill in missing visual information in the same way as their peers. We now need to understand how this may relate to the atypical visual sensory behaviors we see in some autistic children. . spectrum.”
For example, another Knight study published last year found that children with ASD have trouble processing body language if they aren’t paying close attention.
When actively looking at the color of the moving dots on a screen, the brain waves of people with ASD did not interpret the image as a walking human, as expected.
“If their brain processes body movement less, they may have a harder time understanding others and will need to pay close attention to body language to see it,” Knight said in a press release last year. .
“Knowing this can help guide new ways to support people with autism.”
Going forward, Knight hopes to continue her research with larger cohorts, including those with a wider range of verbal and cognitive abilities. Her ultimate goal is to find new and better ways to support children and adults on the autism spectrum.
The study was published in the Journal of Neuroscience.