So far we’ve seen all kind of visual optical illusions: in some of them parts of a completely static picture appear to drift and swirl, in others nothing moves yet they’re blurry, in others reigns the confusion. This kind of moving illusion was created by professor Akiyoshi Kitaoka’s and it’s known as the rotating snake illusion.
What to see?
It’s easy to see on your computer screen a lot of snakes or circles as i like to call them. Each one of them is made of two colors: yellow and blue, with a black dot in the middle.
If you move your look across the image you will notice that the image is moving: some circles move to the right and some to the left. Although if you try to stare at a point that you chose you will observe that the movement cease to exist or it fades as intensity.
How it works?
Your brain has to work hard to disentangle the movements of your eyes, your head on your body, and your body in space for the incoming visual information that are due to your movement and those due to real movement in the world.
Our muscles are constantly sending little corrective signals to keep our eyes in the same place. These signals never keep the eyes exactly still and they produce a fixation movement. If visual stimulation is completely constant, the neurons in the eye stop responding to the constant input and everything fades out. The reason why the movement appears is because of the polarity of the luminance steps.