Jevin West and Carl Bergstrom teach students at the University of Washington how to sort through misinformation in the digital age. Their latest development? A new game called Which Face Is Real that asks you to choose between an image of a real person and an image of a completely fake, computer-generated person, placed side-by-side. It's surprisingly difficult, and they talk with Dave Ross about how fake people, fake videos and even fake audio will soon become nearly impossible to detect.