See how your mind work?

 

Stare at the red dot on this woman's nose for thirty seconds. Then, look over at a blank white space (a piece of paper or an empty browser tab will do). 

Have you done that?

 Did you see the "correct" version of the image? Here's how it works: stare long enough at an object and the eye's photoreceptors (particularly the color-sensitive cone cells) lose sensitivity from overstimulation.

Divert the eyes to a blank space, and the surrounding cone cells send out a much stronger signal. The brain interprets this discrepancy as looking at the precise opposite colors, in what is known as a 'negative afterimage.' Nifty, no?