Another eye-bender

This is from the artist Akiyoshi Kitaka who is a Professor of Psychiatry. The picture is totally static; it is not moving. Don't believe me? Enlarge it by clicking on it, then place your hand on the middle of the screen gradually covering it up. The movement slows down or stops. Quotidian Hopes is not a liar - see the previous post.

What is happening is that the cones in the eye that sense colour are making the eye move to capture the light. Remember that colour only exists in the brain as a processing trick. So it is your eye that is moving very fast (saccade), not the picture. This is called saccadic masking.

So why do we see movement and not a blur? The brain cuts out the blur, so we see an animation with frames of information missing (for fractions of a second) - dropped frames. That is why the picture looks like a cartoon or an animated gif (a graphic seen in web pages, a kind of primitive video).

It is thought that the sensation surviving victims of accidents have where time seems to slow down just before an accident is due to saccadic masking. You are probably thinking that can't be right because saccadic masking would make time speed up! You have forgotten that in a fall or other such frightening experience adrenalin is released. Experiments have shown (including in humans) that the only thing known to suppress the saccadic masking is adrenalin. So, in the fall we see everything as it really is without the brain's censorship, and it is stored instead of being thrown away. So time seems to go slowly.