All Mixed Up: A Solution to the Evolutionary Mystery of Humor

Human social life is filled with coordination problems: passing each other in a hallway, taking turns talking and listening, differentiating the meanings of "hook up with" and "meet up with," gathering at the same time and place, etc. But what happens when we suffer a mix-up—for instance, we get stuck dancing back and forth in the hallway, or I casually mention that I “hooked up” with your mother last night? Here, I argue that such mix-ups posed a significant adaptive problem for our ancestors, disrupting cooperation, damaging reputations, fomenting needless conflict, and destroying valuable relationships. Natural selection favored three solutions to this adaptive problem: 1) a sense of humor (i.e., the ability to detect, anticipate, and avoid mix-ups), 2) mutual laughter in response to humor (which creates common knowledge of the mix-up and defuses its costs), and 3) joking as a hard-to-fake signal of one’s ability to detect and avoid mix-ups (and thus one’s value as a coordination partner). I present a formal model of these phenomena suggesting that agents with a sense of humor, the ability to laugh at (or mutually signal) the humor they’ve sensed, and a preference for partners with a ‘good sense of humor,’ would have been favored by natural selection under conditions that were plausibly characteristic of human evolution. I use the model to shed light on the nature of wordplay, comic timing, practical jokes, awkwardness, embarrassment, mockery, absurdity, mirth, seriousness, impersonations, slapstick, satire, creepy clowns, and cringe comedy.