- This optical illusion, called the Pinna-Brelstaff illusion, exposes a lag in our brains.
- If you focus on the dot in the middle and move your head forward, the outer circle appears to rotate clockwise – move your head back and the motion changes.
- A study at the Chinese Academy of Sciences in Shanghai showed that monkey brains had a 15 millisecond delay when processing motion.
The human brain is a wondrous thing, but it's definitely not perfect, as evidenced by this brain-breaking optical illusion.
In a study conducted by scientists at the Chinese Academy of Sciences, these scientists have shown that the brain experiences and retards when viewing some optical illusions, including the Pinna-Brelstaff illusion.
While it may just look like two circles surrounding a dot, look a bit closer. First, focus on the dot. Then move your head closer ̵
This illusion has been around for years, but it was never clear what caused it.
"It's kind of like if you're at a party where you're listening to a voice among lots of noise," Ian Max Andolina from the Chinese Academy of Sciences told New Scientist. "The physical motion is like a background noise and the illusion is the voice in the noise you have to pick out. It takes a little longer to do that."
Read more: There is an animal hiding in this optical illusion, but you have to shake your head to see it
The study used macaques (a type of monkey they determined to perceive illusory motion similarly to humans) to show that there is a tiny – but significant – delay between the neurons in the brain that perceive motion, aka circles moving, and neurons that perceive local motion. The local motion neurons detect that nothing is actually moving, but it takes them a few beats to catch up with our eyes.
How long does it take your brain to figure it out?