Before you click on the illusion below, remember that you will have to click the back button to return to this page.

When you are looking at the illusion, look at the center of the box for a few moments. Then look at the far left side and far right side of the box for a few seconds. Then come back here.

cal tech illusion

Did you notice that when you look at the center of the box all of the red dots are falling and the green dots are going up, but when you look at the far right and left the opposite is happening: the red dots are going up? Now look at the illusion again, but this time stand back about 5 feet. The illusion no longer exists because you see the division of the box into three parts with left and right doing the opposite of the middle. But close up you can’t see this distinction.

I found this illusion (from Cal Tech’s Shimojo Psychophysics Lab) from a story by Joe Palca on NPR back in 2004 called Tricks the Brain Plays. I thought it was very cool and wanted to share it with you. Mr. Palca explains that the reason this happens is that the brain wants to “bind” color and movement together. As you can our brains are not always accurate. But it is fun!