One morning, the principal’s voice sounded over the intercom of my high school with the shocking announcement that a popular teacher of French had just died in front of his class. Everyone fell silent. While the headmaster went on to explain that the teacher had suffered a heart attack, I couldn’t keep myself from a laughing fit. To this day, I feel embarrassed.
What is it about laughter that makes it unstoppable even if triggered by inappropriate circumstances? Extreme bouts of laughter are awkward: they involve loss of control, shedding of tears, gasping for air, leaning on others, and even wetting of pants while rolling on the floor! What weird trick has been played on our linguistic species, that we express ourselves with stupid “ha ha ha!” sounds? Why don’t we leave it at a cool “That was funny!”?
Philosophers who regard a sense of humor as one of humanity’s finest achievements may find it puzzling that it is expressed with the sort of crude abandon associated with mere animals. But laughter is an inborn, universal human trait, one that we share with our closest relatives, the apes (see “The Laughing Species,” December 2000-January 2001).
[ad: 51 1094]A Dutch primatologist, Jan van Hooff of Utrecht University, set out to learn under what circumstances great apes utter their hoarse, panting laughs, and concluded that ape laughter has to do with a playful attitude. It’s often a reaction to surprise or incongruity—as when a tiny infant chimp chases the group’s top male, who runs away “scared,” laughing all the while. This connection with surprise is still visible in children’s games such as peek-a-boo, or jokes marked by unexpected turns, which we save until the very end and appropriately call “punch lines.”
What intrigues me most about laughter, however, is how it spreads. It’s almost impossible not to laugh when everybody else is. There have been laughing epidemics that lasted months, in which no one could stop for long. There are laughing churches and laugh therapies based on the healing power of laughter. All because we love to laugh and can’t resist joining those laughing around us.
The infectiousness of laughter even works across species. Below my office window at the Yerkes Primate Center in Atlanta, Georgia, I often hear my chimps laugh during rough-and-tumble games, and 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” (as the laugh expression is known), 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. We aren’t 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 individualism and liberty, but members of the species Homo sapiens are easily swayed in one emotional direction or another by their fellows.
That is where empathy and sympathy start—with the synchronization of bodies—not in the higher regions of imagination, or in the ability to consciously reconstruct how we would feel if we were in someone else’s “shoes.” And yet empathy is often presented as a voluntary process, requiring role taking, higher cognition, and even language. Accordingly, most scholarly literature on empathy is completely human centered, never mentioning other animals. As if a capacity so visceral and pervasive could be anything other than biological! To counter such widespread views, I decided to investigate how chimpanzees relate to and learn from one another.
[ad: 51 1121]Empathic synchronization of bodies assumes many forms: moving when others move, laughing when others laugh, crying when others cry, yawning when others yawn. Most of us have reached the advanced stage at which we yawn even at the mere mention of yawning—as you may be doing right now!—but that is only after lots of face-to-face experience.
Virtually all vertebrates, including fish, show the peculiar “paroxystic respiratory cycle characterized by a standard cascade of movements over a five- to ten-second period” that defines the yawn. Chimpanzees yawn when they see others of their species yawn—as do some monkeys, as well as dogs. Yawn contagion, like laughter, also works across species. 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. Notably, children with autism spectrum disorders are immune to the yawns of others, thus highlighting the social disconnect that defines their condition.
Synchrony may be expressed in the copying of small body movements, such as a yawn, but it also occurs on a larger scale, such as group travel. 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 group becomes sleepy and settles down, so you too become sleepy and rest.
Mood contagion serves to coordinate activities, which is crucial for any traveling species (which most primates are). If my companions are feeding, I had better do the same, because once they move off, my chance to forage will be gone. The individual that doesn’t stay in tune with what all the others are doing will lose out, like the traveler who doesn’t go to the restroom when the bus has stopped.
The power of synchrony can be exploited for good purposes. On one occasion in the Netherlands, a herd of some 120 horses got trapped on a patch of dry pasture in the middle of a flooded area. With twenty horses already drowned, people were attempting to save the others. One of the more radical proposals was for the army to erect a pontoon bridge, but the local riding club came up with a far simpler solution. Four brave women on horseback mixed in with the stranded herd, then splashed through a shallow area and, like pied pipers, drew the rest with them in single file. The horses had to swim a few stretches, but all made it safely to terra firma.
Movement coordination both reflects and strengthens bonds. Two horses hitched to a cart, for example, may at first jostle each other and pull at cross-purposes, each following its own rhythm. But after years of working together, the two end up acting like one, fearlessly pulling the cart at breakneck speed through water obstacles during cross-country marathons. They become so attached to each other that they object to even the briefest separation.
Synchrony, in turn, builds upon the ability to map one’s own body onto that of another, and make the other’s movements one’s own, which is exactly why someone else’s laugh or yawn makes us laugh or yawn. Body mapping starts early in life. A human newborn will stick out its tongue in response to an adult doing so, and the same neonatal imitation applies to monkeys and apes. How does the baby know that its own tongue, which it can’t even see, is equivalent to the pink, muscular organ that it sees slipping out from between an adult’s lips? In fact, the word “know” is misleading, because it all happens unconsciously. Scientists may bring up neural resonance or mirror neurons [see “Mental Mirrors,” May 2008], but that hardly makes it less miraculous.
The automatic nature of empathy is revealed through imitation—an anthropoid forte, as reflected in the verb “to ape.” Give a zoo ape a broom, and he’ll move it across the floor the way the caretaker does every day. Give her a rag and she’ll soak it and wring it out before applying it to a window. Hand him a key, and you’re in trouble!
Previous studies of ape mimicry tested whether apes imitated human experimenters in white coats. The results cast doubt on apes’ proclivity for imitation. But my chimps at the Yerkes research center obviously haven’t read the scientific literature: imitating is an integral part of their daily life, and they do so spontaneously, often without any reward in mind. I set up an ambitious research project together with a British colleague, Andrew Whiten of the University of St. Andrews, to find out just how well chimps learn food-obtaining tasks from one another. From an evolutionary viewpoint, it doesn’t really matter what they learn from us humans—all that matters is how they deal with their own kind.
To have one chimp act as a model for another, however, is easier said than done. I can instruct a coworker to demonstrate a particular action ten times in a row, but try telling that to an ape! So first we constructed a puzzle box that can be opened, for example, by using a stick to lift a lever, causing a treat to roll out. We then teach the technique to one member of the group, usually a high-ranking female, and let her demonstrate it for others. Allowed to watch and imitate their groupmate’s new skill, chimps entirely live up to their reputation as apes. They’re literally in one another’s faces, leaning on one another, sometimes holding the model’s hand while she’s performing, or smelling her mouth when she’s chewing the goodies she has won. Such close personal contact—which would be far too dangerous for a human experimenter—makes all the difference. Our chimps often replicate the observed actions even before they’ve gained any rewards themselves. That brings me back to the role of the body.
How does one chimp imitate another? Is it because he identifies with the model chimp, and absorbs her body movements? Or could it be that he focuses on the puzzle box? Maybe all he needs to know is how the thing works. He may notice that a door slides to the side, or that something needs to be lifted up. The first kind of imitation involves reenactment of observed manipulations; the second merely requires technical know-how.
Thanks to ingenious studies by Whiten and others, in which chimps were presented with a so-called ghost box, we know which of those two explanations is correct. A ghost box derives its name from the fact that it magically opens and closes by itself. If technical know-how were all that mattered, such a box should suffice as a teaching tool. But in fact, letting chimps watch a ghost box until they’re bored to death—with its various parts moving and producing rewards hundreds of times—did not teach them anything.
In order to learn from observation, apes need to see actual fellow apes perform an action. Imitation requires identification with a body of flesh and blood. We’re beginning to realize how much cognition in humans and other animals runs via the body. Indeed, bodies figure in everything we perceive or think. The same hill is assessed as steeper, just from looking at it, by a tired person than by a well-rested one. An outdoor target is judged farther away by a person burdened with a heavy backpack than by one without it.
The field of “embodied” cognition is still very much in its infancy, but it has profound implications for how we look at human relations. We involuntarily enter the bodies of those around us so that their movements and emotions echo within us as if they’re our own. This is what allows us, or other primates, to re-create what we have seen others do. Body mapping is mostly hidden and unconscious, but sometimes it “slips out,” as when parents make chewing mouth movements while spoon-feeding their baby.
The same can be seen in other animals. Katharine (Katy) Payne, a biologist at Cornell University, once saw an elephant mother do a subtle trunk-and-foot dance as the elephant’s son chased a fleeing wildebeest. “I have danced like that myself,” writes Payne, “while watching my children’s performances—and one of my children, I can’t resist telling you, is a circus acrobat.”
Not only do we mimic those with whom we identify, but mimicry in turn strengthens the bond. Human mothers and children play games of clapping their own and each other’s hands in the same rhythm. These are games of synchronization. And what do lovers do when they first meet? They stroll long distances side by side, eat together, laugh together, dance together. In romantic situations, a woman will feel better about a date who leans back when she does, crosses his legs when she crosses hers, picks up his glass when she lifts hers, and so on.
This familiar effect may explain why music is just as universal in human societies as language. When many people listen together to the same music, mood convergence and bonding are the result. Examples of similar bonding in other animals are easy to come by, from howling howler monkeys to roaring lions. Take large black gibbons called siamangs, which sing high up in the trees in the Malay and Sumatran forests where they live. For many animals, it’s the male’s job to keep intruders out, but with siamangs—which live in small family groups—both sexes work together toward this end. The female produces high-pitched barks, whereas the male often utters piercing screams that at short range will put every hair on your body on end. Their wild and raucous songs grow in perfect unison into what has been called “probably the most complicated opus sung by a land vertebrate other than man.”
It takes time for a pair of siamangs to learn to sing in harmony, and harmony may be critical to holding onto a partner or territory. Other siamangs can hear how close a pair is, and will move in if they discern discord. Thomas Geissmann, a primatologist at the University of Zürich in Switzerland, observed that deserting an established partner would not be a very attractive option, because the duets of new couples are noticeably poor. He found that couples that sang together a lot also spent more time together and synchronized their activities better. One can tell a good siamang marriage by its song.
According to Ulf Dimberg, a psychologist at Sweden’s Uppsala University, we don’t decide to be empathic—we simply are. Having pasted small electrodes onto his subjects’ faces so as to register the tiniest muscle movements, he presented them with pictures of angry and happy faces on a computer screen. Humans frowned in reaction to angry faces and pulled up the corners of their mouths in reaction to happy ones, even if the pictures flashed on the screen too briefly for conscious perception. That is a rather primitive kind of empathy known as emotional contagion—a first step on the road toward full-blown empathy.
Empathy engages brain areas, such as the limbic system, that are more than 100 million years old. The capacity arose long ago with motor mimicry and emotional contagion, after which evolution added layer after layer, until our ancestors not only felt what others felt, but understood what others might want or need. That ultimately led to sympathy: while empathy is a way we gather information about someone else, sympathy reflects our concern about the other and a desire to improve the other’s situation. Sympathy is anything but automatic. Nevertheless, it is common not only in humans but also in other animals, such as apes, dogs, elephants, and birds.
Apes will groom and hug those in distress. There is also evidence of that behavior in dogs. Belgian biologists watched more than a thousand spontaneous fights among dogs released every day onto a meadow at a pet-food company. After aggressive outbursts, nearby dogs would approach one of the combatants—usually the loser—to lick or nuzzle, play with, or simply sit with him or her. Doing so seemed to settle the group, which quickly resumed its usual activities.
As for its origins, empathy probably started with the birth of parental care. During 200 million years of mammalian evolution, females sensitive to their offspring outreproduced those that were cold and distant. When a pup, cub, calf, or human baby is cold, hungry, or in danger, its mother needs to react instantaneously. Females that failed to respond did not propagate their genes.
Descended as we are from a long line of mothers who nursed, fed, cleaned, carried, comforted, and defended their young, we should not be surprised by gender differences in human empathy. Two-year-old girls who witness others in distress treat them with more concern than do boys of the same age. And in adulthood, women report stronger empathic reactions than men, which is one reason why a “tending instinct” has been attributed to women.
Believing we are seeing a person with whom we have just cooperated receive a painful electric shock (though it’s actually staged) activates pain-related areas in our own brains. That applies to both men and women. But some experiments show that if a man feels he has been duped by someone, he shows the opposite of empathy: when he sees the other’s pain, his brain’s pleasure centers light up. Those men are getting a kick out of the other person’s misery! Women, in contrast, remain empathic. The underlying theme (male lack of empathy for potential rivals) may well be a mammalian universal.
None of this denies male empathy. Indeed, gender differences usually follow a pattern of overlapping bell curves: men and women differ on average, but quite a few men are more empathic than the average woman, and quite a few women are less empathic than the average man. In addition, with age, the empathy levels of men and women seem to converge. Some investigators even doubt that in adulthood there’s much difference left.
Disciplines that view humans as rational decision makers, individually weighing the pros and cons of their own actions, underestimate the way we are influenced by the bodies that surround us, unconsciously responding to voice, mood, posture, and so on. But those influences are what provides the “glue” that holds entire societies together.
Human empathy is so ingrained that it will almost always find expression. As a consequence, at times it must be suppressed. Doctors and nurses in emergency rooms, for example, just cannot afford to be constantly in an empathic mode. They have to put a lid on it. Soldiers must be trained to dehumanize the enemy. Empathy can also be enhanced, as we do when we urge a child who is hogging all the toys to be more considerate of her playmates.
Like other primates, humans can be described either as highly cooperative animals that need to work hard to keep selfish and aggressive urges under control, or as highly competitive animals that nevertheless have the ability to get along and engage in give-and-take. I rank humans among the most aggressive of primates, but I also believe that we’re masters at connecting, and that social ties constrain competition. Many economists and politicians model human society on the perpetual struggle they believe exists in nature. But in fact many animals survive through cooperation, so there is a long evolutionary history to compromise, peaceful coexistence, and caring for others. Empathy is part of the survival package, and human society depends on it as much as many other animal societies do.
[media:node/1558 vertical small right]This article was adapted from The Age of Empathy: Nature’s Lessons for a Kinder Society, ©2009 by Frans de Waal. Published by Harmony Books, a division of Random House, Inc. On sale in bookstores September 22. Click here for ordering information.