Charles Darwin liked to freak out his friends—for science. Guests visiting the famed naturalist in 1868 were shown a set of “ghoulish” photos of a guy being prodded in the face with an electrical current. Darwin then asked his guests-cum-guinea pigs to describe the emotion displayed in each photo. Was the subject happy? Sorrowful? Cheeky? Darwin hoped to determine what universal core emotions exist (if any) and what culturally modified variations branch from them. The result was Darwin’s book The Expression of the Emotions in Man and Animals. Interesting, sure, but not the best science: The Victorian-era crowdsourcing experiment lacked consistent materials, a control group, and enough test subjects—he had only 24.