How optical illusions are illuminating vital medical research

New York — At the Museum of Illusions in New York City, around every corner is a wonder for the eyes. There’s a vase that’s a face, art that moves with you, and a room that seems to go on forever.

It’s a funhouse for our perceptions, built for the TikTok age. But the visual tricks are windows into how the mind works, and they fascinate scientists.

“The brain uses all the information it can get to figure out what’s in front of it,” Dr. Martin Doherty, a psychology professor at the University of East Anglia in England, told CBS News.

Doherty has studied one particular puzzle for years called the Ebbinghaus illusion, an optical illusion which shows how size perception can be manipulated using surrounding shapes.

“The illusion works by using context to mess around with your perception,” Doherty explains.

Doherty long thought that everyone saw the Ebbinghaus illusion the same way. But in a study published in March in the journal Scientific Reports , he and his colleagues found that radiologists who have years of training to ignore visual distractions actually see the image differently and accurately.

In the study, researchers tested 44 experts in “medical image interpretation” — radiographers and radiologists — against a control group of nonexperts consisting of psychology and medical students.

They found that the experts were “significantly less susceptible to all illusions except for the Shepard Tabletops, demonstrating superior perceptual accuracy.”

“According to the theory, that shouldn’t happen,” Doherty said. “It shouldn’t be possible. No previous research has shown that you can learn to see through them.”

One other group has also been shown to solve the illusion, young children. But that ability goes away after age 7, Doherty said.

“We think that’s because it takes time to learn to integrate context into your perception,” Doherty said.

It’s evidence of the deep abilities of a trained brain. But for most of us, illusions are proof of our limitations.

“When you see these visuals, it’s just like your brain just starts going crazy,” museumgoer Kevin Paguay said.

It’s also a reminder that you cannot always believe what you see.