Optical illusions can deceive the brain, allowing those of us who receive them to experience unique experiences. But what's unique is that sometimes not everyone can accept the illusion, one of which is this optical illusion. The illusion of an 'expanding hole'.
If you pay attention, and can accept the illusion well, you will find that the black hole in the photo expands with how long you stare at the image.
From their study published in the journal Frontiers in Human Neuroscience, psychologists from the University of Oslo in Norway found that the illusion of 'expanding holes' is one of the illusions that is quite good at tricking our brains. This illusion encourages people's pupils to dilate.
"The 'expanding hole' is a very dynamic illusion: The circular smear or gradient of shadows from the central black hole evokes the vivid impression of optical flow, as if the observer is heading forward into the hole or tunnel," Dr Bruno Laeng, a professor at the University of Oslo's Department of Psychology and the study's first author, said in a statement.
As part of their research, the team showed these optical illusion images to 50 people with normal vision and asked them to rate how strongly they felt the illusion. Meanwhile, the researchers measured their eye movements, as well as involuntary pupillary constriction and dilation, IFL Science wrote.
The researchers weren't sure why, but not all participants were able to feel the illusion. About 14% of participants did not feel the illusory expansion when the hole was black, while 20% did not feel it when the hole was a different color.
If you are, can you see the optical illusion?