Why do we laugh?Lots of theories have been constructed to answer this question, but most haven`t been terribly successful because we laugh at so many different things. (Here`s a New York Review of Books essay on some of them.) So, let me try out a two-stage theory, which I haven`t actually tested yet against all the different kinds of humor, but it may be promising:Stage One: Let`s start out with a negative but useful definition of humor: it`s not serious.The more something seems serious but is not serious, the funnier it is.King Lear topples rigidly to the ground—uh-oh, that`s serious. Buster Keaton topples rigidly to the ground—oh, good, that`s not serious, ha-ha.A young husband and wife get into an argument over who, exactly, is the father of her unborn child. Generally speaking, that`s not funny. It`s serious.A young husband and wife get into an argument before her parents come for dinner over whether you should set the salad fork to the right of the main fork or across the top of the plate. They start yelling, but eventually start laughing at themselves for yelling because it`s a silly thing to get worked up over. It`s not serious.Laughter happens more in public than in private. To say, as readers often do, that A Confederacy of Dunces or Fear and Loathing in Las Vegas are "laugh out loud funny" is to admit, via the logic of the exception that proves the rule, that the great majority of books don`t provoke loud laughter in solitary readers. In contrast, to say that the recent Katherine Heigl romantic comedy "27 Dresses" is "laugh out loud funny" is ho-hum praise because any movie labeled a comedy is supposed to set the audience in the theatre off laughing.Public laughter can serve as an expression of relief and mutual reassurance that something that could be serious—e.g., the bride`s bedraggled ex-boyfriend crashes into the church just before she says "I do" to the rich guy who doesn`t really love her—isn`t serious, it`s just, say, romantic comedy behavior. Weddings are almost omnipresent in movie comedies these days because we have so few formal ceremonies anymore where A. Americans are supposed to act like proper protocol is all-important; and B. It really isn`t.In mildly stressful social occasions, such as at cocktail parties, people laugh constantly at things other people say that aren`t very funny. (Social scientists have taped and transcribed run-of-the-mill repartee and it`s usually pretty dire). When my feeble witticisms elicit constant giggling, that is people laughing to reassure each other that it`s not serious.That`s laughing-with-you humor, which isn`t normally terribly funny to an outside observer. Professional comedians tend to use laughing-at-somebody humor, which often is. The point of hostile humor is to show us (the audience) that they (the objects of ridicule) aren`t serious. They are ridiculous. It`s reassuring.Top comedians, of course, tend to be notoriously hostile. In the 1990s, a friend once had dinner with Jackie Mason, who spent the entire evening complaining morosely about how Ed Sullivan had ruined his career in 1964. (That`s pretty funny, but only because it wasn`t serious: Mason went on to have a highly successful career, and thus it was funny that he was bitterly lamenting the incident 30 years later. If he had never gotten another break, it wouldn`t be funny, it would be sad.)Perhaps the positive feeling we enjoy when something is funny has evolved as a sort of brain candy to reward us for realizing when something is not serious. Hunter-gatherers can better afford to be ornery because they can just leave when other people get on their nerves too much. Settled humans living in dense populations need other mechanisms for coping with frustrations, such as a sense of humor to reward them for deciding something isn`t really a big deal. Thus, we are primed to search out funny experiences.Stage Two: Assuming that we evolved a craving for the feeling that`s something is funny, then that kind of positive reinforcement could then have evolved to apply to other helpful things. For example, pattern recognition is, generally speaking, a good thing from a Darwinian point of view. So, it`s not surprising that a lot of humor involves pattern recognition.
Q. How many lesbians does it take to screw in a lightbulb?A. That`s not funny!That was funny the first time you heard it (1983) because it crystallized for you something you`d observed evidence for—that lesbians are likelier to be humorless and irritable—but hadn`t yet recognized consciously. Like a trainer teaching Shamu a new trick at Sea World, your brain tossed you some brain candy as a reward for noticing something new. The joke is not very funny now, however, because you already knew lesbians tend to be like that. (By the way, here`s a hilariously unfunny Wikipedia article on Lightbulb Jokes.)So, that`s the theory. Does it account for all types of humor? Well, you can more or less extend stage two indefinitely: Puns are funny because our brains reward us for noticing ... uh ... incongruity. Or maybe our brains toss us some brain candy for noticing that things that seem alike (e.g., homonyms) might not be actually alike (i.e., puns are the inverse of pattern recognition humor).Of course, like most Darwinian explanations, this starts getting unfalsifiable the more you push it.But that leads to the question: