You can't believe your eyes: there's no red in this traffic light

Dean Jackson demonstrated how our brains "work overtime" to see colors that aren't there. He showed a photo of a standard traffic signal with red, yellow, and green lights. Then he placed a cyan filter over the image to block out all the red. But the "red" light still looked red. To prove it wasn't red any longer, he covered up everything but the formerly red light to reveal that it was gray.

Here's another example of how our brains trick us into seeing colors that aren't there. There are no red pixels in this image of strawberries:

Thumbnail image: Alberto Masnovo/