You could train your brain to be less fooled by optical illusions

Optical illusions may make you feel like a fool, but you could be able to train your brain to resist them.

“It is very likely that people from the general population have the capacity to be trained to unsee illusions and perceive the world more objectively,” says Radoslaw Wincza at Lancaster University, UK.

Wincza and his colleagues recruited 44 radiologists, with an average age of 36, who had spent more than a decade spotting small details such as fractures in medical scans. They also looked at 107 university students, average age 23, who were studying medicine or psychology.

Each participant was shown four illusions on a screen, one at a time. In each illusion, the participant saw pairs of shapes or lines of slightly different sizes or lengths, and had to select the larger or longer one.

In three of the illusions, other objects made the larger shape or longer line appear to be the smaller or shorter one. The team found that radiologists were less susceptible to these illusions than the students.

“Radiologists have this ability to really focus on the key elements of the visual scene, where they disregard irrelevant context and have a tunnel vision,” says Wincza. “By better tuning into the target, they don’t experience the illusion as much.”

In the fourth illusion, one of the shapes was vertical, while its pair was horizontal. This made the latter appear wider, even though it was actually narrower. Both groups were equally susceptible to the illusion. That is probably because this one didn’t include any surrounding objects, so it was less about tuning out background distractions, which radiologists may be well practised at, says Wincza.

“It suggests anyone can gain that ability to be less susceptible to illusions if they train themselves,” says Karla Evans at the University of York, UK. For instance, focusing on specific aspects of a picture might improve this ability, though further work is needed to see how quickly this comes about, she says. “It could take years, or weeks.”