iStockphoto
What intrigues me most about laughter is how it spreads. It’s almost impossible not to laugh when everybody else is. There have been laughing epidemics, in which no one could stop and some even died in a prolonged fit. There are laughing churches and laugh therapies based on the healing power of laughter. The must-have toy of 1996—Tickle Me Elmo—laughed hysterically after being squeezed three times in a row. All of this because we love to laugh and can’t resist joining laughing around us. This is why comedy shows on television have laugh tracks and why theater audiences are sometimes sprinkled with “laugh plants”: people paid to produce raucous laughing at any joke that comes along.
The infectiousness of laughter even works across species. Below my office window at the Yerkes Primate Center, I often hear my chimps laugh during rough-and-tumble games, and I cannot suppress a chuckle myself. It’s such a happy sound. Tickling and wrestling are the typical laugh triggers for apes, and probably the original ones for humans. The fact that tickling oneself is notoriously ineffective attests to its social significance. And when young apes put on their play face, their friends join in with the same expression as rapidly and easily as humans do with laughter.
Shared laughter is just one example of our primate sensitivity to others. Instead of being Robinson Crusoes sitting on separate islands, we’re all interconnected, both bodily and emotionally. This may be an odd thing to say in the West, with its tradition of individual freedom and liberty, but Homo sapiens is remarkably easily swayed in one emotional direction or another by its fellows.
This is precisely where empathy and sympathy start—not in the higher regions of imagination, or the ability to consciously reconstruct how we would feel if we were in someone else’s situation. It began much more simply, with the synchronization of bodies: running when others run, laughing when others laugh, crying when others cry, or yawning when others yawn. Most of us have reached the incredibly advanced stage at which we yawn even at the mere mention of yawning—as you may be doing right now!—but this is only after lots of face-to-face experience.
Yawn contagion, too, works across species. Virtually all animals show the peculiar “paroxystic respiratory cycle characterized by a standard cascade of movements over a five- to ten-second period,” which is the way the yawn has been defined. I once attended a lecture on involuntary pandiculation (the medical term for stretching and yawning) with slides of horses, lions, and monkeys—and soon the entire audience was pandiculating. Since it so easily triggers a chain reaction, the yawn reflex opens a window onto mood transmission, an essential part of empathy. This makes it all the more intriguing that chimpanzees yawn when they see others do so.
Yawn contagion reflects the power of unconscious synchrony, which is as deeply ingrained in us as in many other animals. Synchrony may be expressed in the copying of small body movements, such as a yawn, but also occurs on a larger scale, involving travel or movement. It is not hard to see its survival value. You’re in a flock of birds and one bird suddenly takes off. You have no time to figure out what’s going on: You take off at the same instant. Otherwise, you may be lunch.
Or your entire group becomes sleepy and settles down, so you too become sleepy. Mood contagion serves to coordinate activities, which is crucial for any traveling species (as most primates are). If my companions are feeding, I’d better do the same, because once they move off, my chance to forage will be gone. The individual who doesn’t stay in tune with what everyone else is doing will lose out like the traveler who doesn’t go to the restroom when the bus has stopped.
The herd instinct produces weird phenomena. At one zoo, an entire baboon troop gathered on top of their rock, all staring in exactly the same direction. For an entire week they forgot to eat, mate, and groom. They just kept staring at something in the distance that no one could identify. Local newspapers were carrying pictures of the monkey rock, speculating that perhaps the animals had been frightened by a UFO. But even though this explanation had the unique advantage of combining an account of primate behavior with proof of UFOs, the truth is that no one knew the cause except that the baboons clearly were all of the same mind.
Finding himself in front of the cameras next to his pal President George W. Bush, former British prime minister Tony Blair—known to walk normally at home—would suddenly metamorphose into a distinctly un-English cowboy. He’d swagger with arms hanging loose and chest puffed out. Bush, of course, strutted like this all the time and once explained how, back home in Texas, this is known as “walking.” Identification is the hook that draws us in and makes us adopt the situation, emotions, and behavior of those we’re close to. They become role models: We empathize with them and emulate them. Thus children often walk like the same-sex parent or mimic their tone of voice when they pick up the phone.
