Contagious laughter is a distinguishing characteristic of childhood.
Robert Provine wants me to see his Tickle Me Elmo doll. Wants me to hold it, as a matter of fact. A professor of psychology and neuroscience at the University of Maryland, he has been engaged for more than a decade in a wide-ranging intellectual pursuit that has taken him from the play of young chimpanzees to the history of American sitcoms—all in search of a scientific understanding of that most unscientific of human customs: laughter.
The Elmo doll happens to incorporate two of his primary obsessions: tickling and contagious laughter. “You ever fiddled with one of these?” Provine asks, as he pulls the doll out of a small canvas tote bag. He holds it up, and after a second or two, the doll begins to shriek with laughter. There’s something undeniably comic in the scene: a burly, bearded man in his midfifties cradling a red Muppet. Provine hands Elmo to me. “It brings up two interesting things,” he explains. “You have a toy that’s a glorified laugh box. And when it shakes, you’re getting feedback as if you’re tickling it.” (Elmo has been so popular that in September 2006 Fisher-Price released a tenth anniversary version of the doll, called Elmo T.M.X. It not only laughs and vibrates but rolls on the ground pounding its fists, pleading for the supposed tickler to stop.)
Think about that Tickle Me Elmo doll. We take it for granted that tickling causes laughter and that one person’s laughter will easily “infect” other people within earshot. Even a child knows these things. (Tickling and contagious laughter are two of the distinguishing characteristics of childhood.) But when you think about them from a distance, they are strange conventions. We can understand readily enough why natural selection would have implanted the fight-or-flight response in us or endowed us with a sex drive. But the tendency to laugh when others laugh in our presence or to laugh when someone strokes our belly with a feather—what’s the evolutionary advantage of that?
What’s the evolutionary advantage of laughing when someone strokes our belly with a feather?
There is a long, semi-illustrious history of scholarly investigation into the nature of humor, from Freud’s Jokes and Their Relation to the Unconscious, which may well be the least funny book about humor ever written, to a British research group who claimed they had determined the world’s funniest joke. Despite the fact that the researchers sampled a massive international audience in making this judgment, the winning joke revolved around New Jersey residents: A couple of New Jersey hunters are out in the woods when one of them falls to the ground. He doesn’t seem to be breathing; his eyes are rolled back in his head. The other guy whips out his cell phone and calls the emergency service. He gasps to the operator: “My friend is dead! What can I do?” The operator says: “Take it easy. I can help. First, let’s make sure he’s dead.” There is silence, then a shot is heard. The guy’s voice comes back on the line. He says, “OK, now what?”
This joke illustrates the notion of controlled incongruity: You’re expecting x, and you get y. In the hunting joke there are two plausible ways to interpret the 911 operator’s instructions—either the hunter should check his friend’s pulse, or he should shoot him. The context sets you up to expect that he’ll check his friend’s pulse, so the—admittedly dark—humor arrives when he takes the more unlikely path. That incongruity has limits, of course: If the hunter chooses to do something utterly nonsensical—untie his shoelaces, say, or climb a tree—the joke wouldn’t be funny.
When Provine set out to study laughter, he imagined that he would approach the problem along the lines of these humor studies: having people listen to jokes and other witticisms and then watching what happened. He began by simply observing casual conversations, counting the number of times that people laughed while listening to someone speaking. But very quickly he realized that there was a fundamental flaw in his assumptions about how laughter worked. “I started recording all these conversations,” Provine says, “and the numbers I was getting—I didn’t believe them when I saw them. The speakers were laughing more than the listeners. Every time that would happen, I would think, ‘OK, I have to go back and start over again because that can’t be right.’ ”
