10 Mind Melting Illusions (And Exactly How They Work)

3. Rotating Snakes

This is possibly one of the most well-known optical illusions out there, but it doesn't mean it doesn't still melt our minds. We've all tried staring steadily at this, trying desperately to get it to sit still, but it's frustratingly difficult.

This migrane-inducing illusion, created by Akiyoshi Kitaoka, is all thanks to a little thing called the peripheral drift illusion (PDI) and, despite its fame, we're still not quite sure what causes it. It is thought that it has something to do with the “saccades”, or tiny micro movements made by the eyes to prevent them from becoming colourblind, as we discussed earlier, that cause the snakes to appear to writhe.

We can't detect the saccades in your normal vision, because our brain corrects for them, but something about them causes us to perceive motion in the image above.

Interestingly, studies of the PD phenomenon suggest that there could be a genetic element contributing to how different people perceive the motion.