THE OLD SLEEP EXCUSE, OFFICER! I THOUGHT THE LIGHT STILL GREEN!

Sleep can change a person's color perception. That's the finding of a study from the University of Houston. Researchers ran visual tests on people at different stages of alertness. They found that when the subjects were tired, they classified a sample of the color gray has having a slightly greenish tint. After nearly eight hours of sleep, they identified the same sample as being gray again. The scientists aren't sure what causes the phenomenon. This excuse will not work with your friendly police officer. (I'm tired and the light looked green, officer.)