Your Brain Wants To Make Your World Make Sense
When you do this simple experiment, here’s what’s happening. Your brain is creating a Negative Afterimage. When you stare at the negative image, the photoreceptors, which are the parts of your eyes that “receive light” get overstimulated and fatigued (tired), which causes them to lose sensitivity. In regular situations, you don’t even notice this because the little movements of your eyes keep your cone cells, one of the two kinds of photoreceptors, from getting overstimulated.
But, when you stare at a large image, the tiny movements in your eyes aren’t enough to reduce that overstimulation. So, you start to experience what is known as a negative afterimage. When yo shift your eyes to look at the white box, your overstimulated cone cells keep on sending the image information to your brain. That has the effect of “muting” the colors being transmitted.
Then the photoreceptors that aren’t overstimulated start to send strong signals that are the opposite of the colors you were seeing before. I know, it’s a little confusing. The result is that your brain, wanting to make sense of your world for you, sees these afterimage signals as the opposite colors. A negative of a negative, as it were. This creates a color image of the negative you were staring at.
How Cool Is That!