The image above is an optical illusion. And, by the way, it is a static image, not a GIF or whatever, so nothing it’s moving in it, even though your brain thinks otherwise. That is known as a Pinna-Brelstaff illusion, and, recently, a team of experts explained it for the first time in history. According to a recent study, this optical illusion tricks your mind into believing that the circles in the pic are moving by making your brain “lag.”
More specifically, the scientists explained, this Pinna-Brelstaff illusion is creating a delay in the communication between different regions of the human brain. To experience this optical illusion to its maximum, lean your head towards the image, and you’ll notice that the dash lines and circles are moving clockwise. Then, lean back just to see that, now, the rings in the photo are rotating in the other direction.
“It’s kind of like if you’re at a party where you’re listening to a voice amongst lots of noise. The physical motion is like background noise, and the illusion is the voice in the noise you have to pick out. It takes a little longer to do that,” explained Ian Max Andolina from the Chinese Academy of Sciences.
Here’s One Optical Illusion That Makes Your Brain “Lag”
In their study, the scientists used macaques because they possess a vision processing system similar to, humans. The researchers installed electrodes in the animals’ brains to measure what’s going on in their heads when watching that optical illusion.
The readings revealed a 15-millisecond delay between the activity of neurons that perceive global motion, meaning that this specific optical illusion makes the brain “lag.”
“As you move your head in and out, the way these elements slide across your retina is going to have two motion directions: an outward expansion, but also the rotation induced by the fact that the edge is slanted. That’s different from something that just rotates or just expands, so you might expect that it takes a little more work to resolve what the motion is telling you,” also said Paul Azzopardi from the University of Oxford.