Mark Changizi (born 1969) is an American theoretical cognitive scientist and entrepreneur. He is recognized for his research into the evolutionary origins of biological and cognitive design. His notable contributions include the "Perceiving the present" hypothesis for optical illusions, the "Nature-Harnessing" theory for the origins of writing, speech, and music, the skin-signaling hypothesis for primate red-green vision, and the rain-tread hypothesis for pruney fingers.