The Age of Empathy (18 page)

We take such abilities for granted, but have you ever noticed that
not everyone takes advantage of them? I’m talking about adults here, such as the two kinds of gift givers we’re all familiar with. Some friends will go out of their way to find you a gift that
you
might like. Knowing that I love opera or play the amateur baker at home, they buy me a CD of the latest Anna Netrebko performance or the best rye flour in town. I always feel that the amount of money spent is secondary to the thought, and these people are clearly intent on pleasing me. The other kind of gift giver arrives with what
they
like. They’ve never noticed that we don’t have a single blue item in the house, but since they love blue, they bestow an expensive blue vase upon us. People who fail to look beyond their own preferences ignore millions of years of evolution that have pushed our species to ever better perspective-taking.

Every day, humans are prepared to improve the lives of others, including complete strangers, provided it isn’t too much trouble. Strictly speaking, this isn’t altruism, because altruism requires an effort. No, I am talking here of a situation that doesn’t set you back one bit. An example is what happened during a hike my wife and I once took in Canada. This was during our early days in North America, when every distance seemed ten times longer than we’d ever imagined. We were trying to escape from a lakeshore where giant mosquitoes were eating us alive and had decided to walk to the nearest town. We walked and walked over a never-ending dirt road under a bright sun. A large station wagon with a Canadian family slowed down next to us and the driver nonchalantly leaned out, asking “Do you need a ride?” When he told us how far the town still was, we were more than happy to accept. I still feel grateful.

Low-cost assistance is common in humans, such as one tennis player helping up another.

This is so-called low-cost altruism, when one isn’t going
much out of the way for someone else but still offers substantial help. We do it all the time. If someone at the airport drops his boarding pass and I alert him to it, it costs me very little, but saves my fellow passenger much grief. We also customarily hold the door that we just went through for someone who comes after us, slide aside on a park bench for someone who wants to sit, hold back an unknown child who’s about to run onto the street at the wrong moment, or help an older person lift a heavy piece of luggage. Humans are great at this sort of assistance, at least under relatively comfortable circumstances, because the behavior vanishes as soon as the
Titanic
starts foundering. Under hardship, the cost of civility goes up.

To be considerate, even in small ways, one needs empathic perspective-taking. One needs to understand the effect of one’s behavior on others. As I search for possible animal parallels, a curious behavior comes to mind that I saw among wild chimpanzees while standing in an almost dry river bed in the Mahale Mountains in Tanzania. The chimps were relaxing on large boulders, grooming one another. I had read about their so-called
social scratch,
but never seen it firsthand.

Social scratching occurs when one ape walks up to another, vigorously scratches the other’s back a few times with his fingernails, then settles down to groom the other. More back-scratching may follow during the grooming session. The behavior itself cannot be hard to learn for an animal that commonly scratches itself, but here’s the rub: When one scratches oneself, this is usually in order to relieve itching (try not to scratch yourself for an hour, and you’ll appreciate its importance). But scratching someone else’s back is something else entirely: It doesn’t do any good for the scratcher himself.

Unlike grooming, the social scratch is unlikely to be innate. We know this, because curiously only the Mahale chimps show this behavior. It hasn’t been documented in any other chimpanzee community. Anthropologists and primatologists call such group-specific behavior a “custom.” Customs are habits that are passed on within a community and are unique to that community. Eating with knife and
fork is a human custom in the West, and eating with chopsticks a custom in the East. By itself, finding customs in chimpanzees is not that special, because these animals have lots of them, more than any species apart from ourselves. The real puzzle is how members of the Mahale community came to adopt a custom that favors others more than themselves.

How did the Mahale chimpanzees develop an other-serving custom? The middle individual scratches another’s back with long strokes.

How do we learn to hold a door open for others? You might say that we have been told to do so by our parents, which is undoubtedly true, but later on such habits are reinforced by experiencing them and appreciating the favor. From this we figure it might be nice to do the same for others. Could this be how the social scratch spread among the Mahale chimps? Imagine that one ape was accidentally scratched by another, and it felt so good that he decided to offer the same experience to a third, perhaps one whom he wanted to ingratiate himself with, such as the boss. This is entirely possible, but would imply perspective-taking. The scratcher would need to translate a bodily experience into an action that re-creates the same experience in somebody else. He’d need to realize that others feel what he feels.

The social scratch is a deceptively simple act, behind which dwells a profound mystery that can’t be resolved by observations alone. I could watch as many of these interactions as Toshisada Nishida, my host in Mahale, has seen in his four decades in the field, and would still have no clue what’s behind them. We cannot ask the chimps why they do it, and we are too late to witness the first social scratch, the one that seeded the custom. This is where research in captivity offers a solution: Problems from the field can be taken into a setting that allows systematic testing. We can see, for example, how sensitive primates are to another’s welfare if we give them the opportunity to do small favors.

Over the last few years, interest in this question has grown. Let me start with two simple studies with our own capuchin monkeys. I have two groups of these cute brown monkeys. They have outdoor space, where they can sit in the sun, catch insects, groom, and play. There’s also an indoor area with doors and tunnels that make it easy to move them into tests. They are used to the procedures, and actually eager to be tested, which almost always involves attractive food. The capuchin is a favorite primate for these kinds of experiments, because they are extremely smart (they have the largest brain relative to body size of all monkeys), share food, and cooperate easily with one another as well as with humans. They are such appealing monkeys that my students have pictures of their darlings on the wall and passionately talk about them as if they’re discussing a soap opera.

Our first experiment tested whether these monkeys recognize the needs of others. Do they understand when one among them is hungry? They indeed seem to do so, because we found that their willingness to share food with another depended on whether they had seen the other just eat. They shared more with a monkey who’d been empty-handed than one whom they’d seen munching on food.

The second experiment was even more revealing since it suggested interest in another’s welfare. We placed two monkeys side by side: separate, but in full view. One of them needed to barter with us, which is something these monkeys understand naturally. For example, if we leave a broom behind in their enclosure, all we need to do is point at it and hold up a peanut, and the monkeys understand the deal: They bring us the broom in exchange. In the experiment, the bartering was done with small plastic tokens, which we’d first give to a monkey, after which we’d hold out an open hand, letting them return the token for a tidbit.

The interesting test came when we offered a choice between two differently colored tokens with different meaning: One token was “selfish,” the other “prosocial.” If the bartering monkey picked the selfish token, it received a small piece of apple for returning it, but its partner got nothing. The prosocial token, on the other hand, rewarded
both monkeys equally at the same time. Since the monkey who did the bartering was rewarded either way, the only difference was in what the partner received. To make sure they understood, Kristi Leimgruber, my assistant, would make quite a show by raising either one hand with food and feeding one monkey, or raising both hands and simultaneously handing food to both of them.

We know exactly how socially close any two monkeys are because we watch how much time they spend together in the group. We found that the stronger the tie with its partner, the more a monkey would pick the prosocial token. The procedures were repeated many times with different combinations of monkeys and different sets of tokens, and they kept doing it. Their choices could not be explained by fear of punishment, because in every pair the dominant monkey (the one who had least to fear) proved the more prosocial one.

Does this mean that capuchin monkeys care about the welfare of others? Do they like to do them favors? Or could it be that they just love to eat together? If both monkeys are rewarded, they will sit side by side munching on the same food. Do things taste better together than alone, the way we are more at ease having dinner with family and friends? Whatever the explanation, we showed that monkeys favor sharing over solitary consumption.

Similar experiments with apes initially failed, leading to premature headlines in the media such as “Chimpanzees Are Indifferent to the Welfare of Unrelated Group Members.” But as the old saying goes, absence of evidence is not evidence of absence. All that we seem to have learned from these experiments is that humans can create situations in which apes put their own interests first. With regard to our own species, too, this wouldn’t be hard to do. Take the way people trample one another to get to the merchandise when a department store opens its doors for a major sale. In 2008, a store employee was killed in the process. But would anyone conclude from these scenes that humans, as a species, are indifferent to one another’s welfare?

Successful approaches often require a flash of insight into what best suits a particular animal. Once achieved, the false negatives will
be forgotten. This is what happened when Felix Warneken and colleagues of the Max Planck Institute in Leipzig, Germany, hit on a winning formula to test ape altruism. They worked with chimpanzees at a sanctuary in Uganda, where the apes spent their days on a large, lush island with lots of trees. Every night they were brought inside a building, which is where the tests took place. A chimp would watch a human unsuccessfully reach through the bars for a plastic stick. The human would not give up, but the stick would stay out of reach. The chimp, however, was in an area where he could just walk up to the stick. Spontaneously, the apes would help the reaching person by picking up the desired item and handing it to him. They were not trained to do so, and rewarding them for their effort made no difference. A similar test with young children led to the same outcome.

When the investigators increased the cost of helping, by having the apes climb up a platform to retrieve the stick, they still did so. The children also helped even if obstacles were put in their way. Obviously, both apes and children spontaneously help others in need.

But could it be that chimps in a sanctuary help humans because their lives depend on them? Prepared for this argument, the investigators had selected human partners who were barely known to the apes, and certainly not involved in their daily care. They further added a second test to see if the apes would assist one another in the same way.

From behind bars, one chimpanzee would watch a partner struggle to open a door leading to a room where both knew there was food. The room was closed, however. The only way to get in would be if a chain blocking the door were removed, but this chain was beyond the control of the partner. Only the first chimp could undo it. The outcome of this particular experiment surprised even me—I wasn’t sure what to predict given that all the food would go to the partner. Yet the results were unequivocal: One chimp removed the peg that held the chain, thus allowing its companion to reach the food.