A new “expanding hole” illusion is strong enough that we’re both physically and mentally fooled, according to new research.

The illusion depicts a black hole in the centre of a white background covered in smaller black circles and, if you’re one of the 86 percent of people tricked by it, the black hole will look like it’s expanding.

According to the researchers who studied this illusion, which is completely new to science, those who were fooled by the illusion had a physical reaction, with participants’ pupils dilating as if they were actually moving into a dark area.

Does it look like the black hole is growing? You’re not alone in thinking that, according to this new study. Image: Supplied

Dr Bruno Laeng, a psychology professor at the University of Oslo and the study’s first author, said the illusion showed that our pupils react to light we perceive, “even if this ‘light’ is imaginary”.

“The ‘expanding hole’ is a highly dynamic illusion: the circular smear or shadow gradient of the central black hole evokes a marked impression of optic flow, as if the observer were heading forward into a hole or tunnel,” he explained.

“Here we show based on the new ‘expanding hole’ illusion that the pupil reacts to how we perceive light – even if this ‘light’ is imaginary like in the illusion – and not just the amount of light energy that actually enters the eye.

“The illusion of the expanding hole prompts a corresponding dilation of the pupil, as it would happen if darkness really increased.”

After having tested the illusion using holes of varying colours – including blue, cyan, green, magenta, red, yellow and white – the team found the illusion was most effective when it was black.

They also discovered that a black hole would cause the pupil to dilate, while coloured holes would result in the eye constricting.

The study, published in the journal Frontiers in Human Neuroscience, shows that these kinds of illusions are more than just gimmicks, with researchers in the field of psychosociology studying them to better understand how the complex system that allows us to see and make sense of the world around us works.

Image: Supplied

This article first appeared on OverSixty.