Not So Different After All
Frans de Waal On Animal Intelligence And Emotions
BY MARK LEVITON
For a long time the Dutch American ethologist and zoologist Frans de Waal was told by senior scientists that studying emotions in animals was off-limits. But while working with chimpanzees and other primates in the Netherlands in the 1970s, he observed behaviors that seemed to match human expressions of emotions — and why not? Chimps are our closest animal relatives. In the last twenty-five years many scientists have caught up with de Waal’s observations, and the notion that animals have emotions is no longer so controversial. Over the course of his long career he has conducted studies showing that our fellow mammals exhibit jealousy, grief, forgiveness, and more. He believes there “are no uniquely human emotions.”
His latest book, Mama’s Last Hug, takes its title from an emotional display de Waal witnessed between Mama, the matriarch of the chimpanzee colony at the Royal Burgers’ Zoo in the Netherlands, and de Waal’s biologist mentor Jan van Hooff, the cofounder of the colony. For decades Mama had been the loved and respected “alpha female” of her primate community, brokering reconciliations, soothing hurt feelings, and building coalitions. Before she died in April 2016, just shy of her fifty-ninth birthday, van Hooff, then seventy-nine, paid her a final visit. In a tender embrace captured on camera, Mama stroked van Hooff’s white hair despite the arthritis in her hands. The trust and love between these two elderly hominids was palpable. After Mama died, the other chimps washed and groomed her body. “For me,” de Waal writes, “the question has never been whether animals have emotions, but how science could have overlooked them for so long.”
As he details in his book, de Waal had a close relationship with Mama, too. He was the one who’d named her in the 1970s, while studying primates at the Royal Burgers’ Zoo. He had said goodbye to her months earlier, before returning to his work at the Yerkes National Primate Research Center at Emory University in Atlanta, where he is director of the Living Links Center.
De Waal earned his PhD in biology from the University of Utrecht before moving to the United States in the 1980s; published his first popular book, Chimpanzee Politics, in 1982; and has since become a world-renowned expert on the similarities and differences between human and other animal behavior. He has studied capuchin monkeys, elephants, the crow genus of birds, and other species — but most extensively our closest primate relatives, chimpanzees and bonobos. When we scratch our scalps while solving a problem, he says, or feel the hairs on the back of our necks stand up when frightened, or brush a loose hair from the shoulder of our spouse, we are exhibiting typical primate behavior.
De Waal is also the author of The Age of Empathy, The Bonobo and the Atheist, and Are We Smart Enough to Know How Smart Animals Are? His articles have been published in Science, Nature, Scientific American, and professional journals specializing in animal behavior and cognition. In 2007 Time named him one of its hundred most influential people in the world. His TED Talks and lectures have been viewed and shared millions of times online, and he’s a frequent guest on radio and television programs.
Now seventy-one years old, Franciscus Bernardus Maria de Waal — “Frans” for short — lives in Smoke Rise, Georgia, with his wife, Catherine. I had arranged to interview him in person before the COVID-19 pandemic made travel inadvisable, but he agreed to meet via video chat instead. We quickly overcame the awkwardness of relating through a computer screen and had a wide-ranging discussion interrupted by a few Wi-Fi glitches. He speaks excellent English, although at times his accent and sentence structures reveal his Dutch roots. At one point, while we discussed our childhood pets, he moved his camera to show me one of his many tropical-fish tanks. “The big fish do sometimes eat the little fish, so you have to be careful which ones you mix together,” he said. It wasn’t the last time he would point out that the natural world contains plenty of danger, along with great beauty and complexity.
Leviton: Darwin wrote that the difference in mind between humans and higher animals is “one of degree and not of kind.” What do you think he meant?
De Waal: I think Darwin meant that the way we think is not fundamentally different from the way other species think, and I’m completely in agreement with him, even though people have attacked him for it over the years and said this was one of the things he was wrong about. There are some elements to human thought processes that are special, but the whole structure of cognition — how it works, what we can comprehend, how we find solutions to problems — is not so different. Human cognition is a variety of animal cognition.
Leviton: Why do you think some people have such a hard time accepting that idea?
De Waal: It’s strange, especially at a time when neuroscience is showing us the similarities between the monkey brain and the human brain. For instance, there’s no part of a human brain that you don’t also find in a monkey brain. There are no synapses or transmitters that are different. Even the blood supply is the same. We do have bigger brains, it’s true, which is certainly important.
Let me tell you a funny story about that. Five or six years ago some scientists were saying maybe we shouldn’t look at the brain’s size; the number of neurons might be a better measure of the brain’s power. And we thought humans came out on top in terms of neurons, so that was fine with everybody — until we found that elephants actually have three times as many neurons as humans. Certain people scrambled for an explanation of that, and now we don’t hear as much about counting neurons anymore.
That’s typically the human attitude: we need to be on top, and some people don’t want to hear about any evidence that animals can do things we cannot do or have some abilities we don’t have. For example, bats use echolocation, determining position by sending out and receiving sound waves, which is extremely complex. Ask any engineer who designs radar systems for airplanes. But because we are, in our minds, far above bats in the hierarchy of species, they don’t impress us.
Chimpanzees are our closest genetic relatives, and when they show extraordinary ability, some researchers get upset. Ayumu is a chimpanzee who lives at the Primate Research Institute in Kyoto, Japan, and his memory puts human memory to shame. He can remember the location and order of numbers flashed on a screen better than most humans. And though humans become less accurate when the time they see the numbers is shortened to 210 milliseconds, it doesn’t bother Ayumu. When he competed against a British memory champion, who was known for his ability to memorize an entire stack of cards, Ayumu won the contest.
We always look for traits that mark humans as special. Language is such a strong marker of humanity that in the eighteenth century a French bishop was ready to baptize an ape if he could demonstrate speech. In the 1950s we tried to teach language to apes, and it turned out they weren’t so great at it — not even at the level of a three-year-old child. But the apes still did much more than we thought they would, so the findings were hotly debated.
Leviton: We know animals communicate. Why isn’t that considered language?
De Waal: Linguists originally defined language as “symbolic communication.” Then apes showed the ability to use two or three hundred symbols, so linguists switched the definition: now language was not just symbolic; it had to be syntactical, meaning it had to have identifiable rules and processes governing structure. Even though we have a few studies that show a limited amount of syntax in animal communication, that’s still the dividing line. But it’s interesting that linguists had to change their definition as a result of the achievements of animals.
Apes aren’t the only nonhuman creatures capable of using symbolic communication. Bees dance to communicate about things they cannot presently see. The duration of a dance indicates geographical information about food sources, for example.
Leviton: It seems to me we don’t look at an animal’s life the way we look at our own. It’s like we don’t want to admit that bats are every bit as good at being bats as we are at being human.
De Waal: Yes, it’s a very anthropocentric enterprise. People sometimes ask me about ape-language studies, which have never impressed me. They say, “Don’t you want to talk to your chimps?” Well, no. I personally don’t see what I would get out of that. I’m much more impressed by how they communicate with and relate to other chimps.
We did experiments in which chimpanzees could work together on an apparatus, and we found they had ways of recruiting each other that we did not understand. We’d see a chimp approach another, and then they would walk to the machine we’d set up and start working together as if they’d agreed to collaborate. We’ve never figured out how they communicated the plan.
All species have complex communication. Dolphins produce a signature whistle, a high-pitched sound with a modulation that is unique for each individual. Females keep the same melody for their whole lives, but the males adjust their melody over time, until all the calls within a male alliance sound alike. We haven’t yet discovered why.
Leviton: Tools were once an important marker of human superiority. How do animals compare to us in their use of tools?
De Waal: The first studies that dealt with animal cognition were about the use of tools by chimpanzees. These were done by German psychologist Wolfgang Köhler a century ago. He was very much hated by the behaviorists — led by the American psychologist B.F. Skinner — who believed all animal behavior was the result of associative learning [a process in which a behavior is followed by a positive or negative stimulus that reinforces or discourages the behavior in the future — Ed.]. I’ve been at meetings where the behaviorists could not even pronounce the name Köhler, because they would be so upset. Köhler, Köhler! [Laughs.] He was the first to say animals could think, based on his work with chimpanzees. He’d hang a banana very high and give chimps sticks and boxes. And he would not train them. Behaviorists train their test subjects by giving them little rewards for every move they make. Köhler wouldn’t do that. And, after a half hour or so, one of Köhler’s chimps would stack the boxes, climb up with a stick, and get the banana. He concluded that this chimp had had an insight — in German, Einsicht — and solved the problem in his or her head. This was the opposite of what animals were supposed to do. They were supposed to operate completely on trial and error.
Now we have “insight learning” studies on all kinds of species, not just apes. Edward Tolman, who studied rats and has a building named after him at the University of California, Berkeley, talked about rats’ “mental maps.” A rat doesn’t just learn to go right or left as a result of behavioral rewards, Tolman said; he develops a map in his head of the whole maze.
The reason Tolman ended up in Berkeley was because the East Coast establishment were strict Skinnerians [followers of B.F. Skinner]. It wasn’t until the 1990s that we finally started to win the battle with the behaviorists, and those who talked about animal cognition got a foothold and got funding for experiments. We don’t yet have a grand theory of cognition, but at least we have abandoned Skinner’s reductionist idea that it’s all mechanical, a result of reward and punishment.
Leviton: When I studied psychology in the 1960s, I remember it being very divided between behaviorists and those I thought of as humanists. The Skinnerians believed people, too, were like automatons. There was something almost fascistic about it.
De Waal: Skinner’s utopian novel Walden Two, written in 1948, is a rejection of free will and posits that cultures and people can be engineered to be a certain way. So, yes, behaviorism had that element, that emphasis on control. I was trained in Europe, where Skinner was not nearly as strong an influence. In the U.S. behaviorism was almost a religion. My book Are We Smart Enough to Know How Smart Animals Are? has a lot in it about these battles with behaviorists. People who read it now may wonder what all the fuss was about, but it was a big deal at the time.
How much we know now about animal cognition and animal emotions is uncomfortable for some people. It does mean we need to pay attention to how we treat animals.
Leviton: In philosophical and practical terms, what’s the difference between studying animals in laboratory conditions and in the wild?
De Waal: There used to be a tremendous amount of tension surrounding this. Initially we considered fieldwork nonscientific. Places like the Yerkes National Primate Research Center, which was established in 1930, were the standard. We worked with captive apes, and we did controlled experiments. When researchers went into the wild and saw glimpses of apes’ natural behavior, other scientists were not impressed. Then people like Jane Goodall went into the field in the early 1960s and stayed longer. They didn’t just see glimpses. They were living with the chimps. They watched their behavior develop over time, saw them raise their young, and started to recognize all the individuals in a community. Then fieldwork became more serious, and we began to respect it. The field-workers started to look down on work with captive apes and criticized the artificial environment the apes lived in as a kind of prison.
Now the field-workers are encountering difficulties because ape habitats are under threat or have disappeared. And they need labs, because they want to analyze feces and urine and blood samples. They want to examine the DNA of animals or their hormone levels. So we have lots of collaboration between laboratories and field-workers. We’ve found a balance.
Experiments with captive apes have also gotten much more advanced. We sometimes discover things field-workers don’t know about. For example, when I was a student, I found out chimpanzees sometimes reconciled after fights. It was only twenty or thirty years later that field-workers observed that process in the wild. So sometimes the knowledge flows one way, sometimes the other. We realize it’s basically different pieces of the same puzzle. I can solve in captivity some issues the field-workers can never solve, and they can see natural behavior I might never see in captivity. We need each other to arrive at a full picture of a species.
Leviton: Don’t the field-workers in primatology have the same problem that anthropologists have — that their own presence influences the behavior of their subjects and skews the data?
De Waal: Yes, in the field someone might work on baboons and conclude that they very seldom suffer predation, but it’s partly because the researchers’ presence scares away the predators. Pristine environments don’t exist anymore, and the human presence affects everything.
It’s the same in captivity. We influence the animals there, too. But captive research has advantages in some situations. In the field, if there’s a big fight involving ten chimps, most of the participants will disappear for long periods, and researchers have to reconstruct what happened from clues. There’s a lot of speculation there. In captivity I can see the subjects at all times. If there’s a fight, I know exactly how it started and ended.
Leviton: How is your facility designed to let you observe?
De Waal: The chimps live in a large outdoor enclosure with grass and a climbing structure. We have a building and can try to call them in by name, but they come only if they want to come. We can’t force them. The building has food and air-conditioning, so there are certain incentives for them to come inside. They usually stay for less than an hour. Our big challenge is to get certain individuals to come in. Maybe we want A and B to do a test, not C and D. But A has a big fight with B, so that’s not going to happen today.
Once they are in the building, we offer touch-screen tasks or a cooperation task, where they can give each other tokens or food. After the experiment, we send them out again. Our experiments never involve anything painful or problematic. If we did that, they would never come inside again! [Laughs.] We want them to leave in a good mood.
Leviton: Can they decide to come in themselves when they want to?
De Waal: We haven’t managed to do that. We have to let them in. But at the Kyoto Primate Research Institute, the chimps live in an open area and can come in anytime to work on a computer. And the researchers have a camera at the computer, so they know who is generating the data. The chimp might work for ten minutes, then leave.
Chimps love computers. You don’t even need to reward them with food to get them to use one. When we first started using computers, we didn’t have touch screens; we had joysticks. We started very simply. For example, there would be a big red dot on the screen, and the chimps would use the joystick to move a cursor to the dot. As soon as they did, they got a reward. From there you move on to more-complex tasks.
Some have argued that the move from a hunter-gatherer way of life to agriculture and the domestication of animals was the worst decision Homo sapiens ever made. It profoundly changed our relationship to animals.
Leviton: The ethologist Konrad Lorenz, whom you call “the maestro of observation,” believed love and respect were necessary conditions for doing effective investigations of the lives of animals. What did he mean when he urged “holistic contemplation” of other species?
De Waal: Biologist E.O. Wilson, who studies ants, has said there are two types of biologists: The naturalists, like Lorenz and himself, who want to understand the whole organism in all its ecological relations, cognition — everything. And the specialists, who want to know one thing — for instance, what is the best reward schedule for a pigeon to learn a specific behavior? The animal itself and everything that comes with it is of no particular interest to them.
We have a lot of specialists nowadays, and I find it a little disturbing to meet a student who’s going into the field with a very specific hypothesis to test. I always ask, “Why would you have that hypothesis before you’ve even seen the animals? Why don’t you just absorb what they do, and then develop your ideas about them?”
What Lorenz meant by “holistic contemplation” is the desire to know everything about another species: how they lay eggs, how they raise babies, what they eat — even if some of it isn’t part of your initial interest. Everything you learn, placed in the bigger context of the animal’s life, makes it more interesting, in my opinion.
Most primatologists really love their animals and are passionate about their lives. But you sometimes also meet scientists who don’t particularly like their animals. These people do exist. They’re very rare among primatologists, though.
It also helps to be open to surprises. That’s true of all sciences. People who keep their eyes open pick up on things that are new and are ready to dive into them. Other people go around with blinders. They have a theory, and everything has to fit into the theory. Everything that falls outside the theory, they don’t see. Most of us are open-minded.
Leviton: Did you have that type of open-minded curiosity when you were a child?
De Waal: Yes, I always had animals as a child — fish and salamanders and birds and mice. I read everything I could about them, at a time when there really wasn’t that much to read — at least, in the Netherlands. When I went to the university as an undergraduate biology student, I was disappointed because all I saw were dead animals. They had us cut up rats and other animals, and plants also. I saw the inside of animals but not their behavior. For my doctorate I went to the University of Utrecht, where I began to study with Jan van Hooff, and I eventually wrote my dissertation about the behavior of macaques.
Leviton: As a child I had pets like fish and turtles, but their deaths really bothered me. In some cases — like when my guppy gave birth and gobbled up her offspring — I was truly horrified. It put me off having pets for the rest of my life. You must have seen a lot of violent behavior studying animals. How do you deal with it?
De Waal: It’s true. Chimps can be violent, even brutal, with each other. They can kill each other. We’ve had it happen. I see this as being part of nature. After my last book, Mama’s Last Hug, which is about animal emotions, I’m often asked if I eat meat. I do. I know very few vegetarian or vegan biologists. I think it’s because we see all kinds of animals eating each other. We don’t find it morally reprehensible; it’s just how nature works. Now, the treatment of farm animals — that I see as a problem. But the eating part, no. The lion eats the antelope. We like the lion, and we like the antelope. This is just the way it is. You have to get used to it.
Leviton: I guess I see this as part of a larger question: Even if we evolved to eat meat, can’t we use our moral sense to overcome that part of our nature?
De Waal: I could see a nutritional argument, an ecological argument, or an animal-welfare argument for vegetarianism, but the eating of meat is not intrinsically immoral, in my opinion. As a biologist, that’s how I look at the world.
One of the convenient things about behaviorism was that it simplified the moral question by claiming animals were dumb. Animals didn’t have emotions, cognitive processes, consciousness. So you could do whatever you wanted with them: keep pigs in tiny lockups, put a bolt into the cow’s head. The moral convenience of behaviorism may be why it lingered for so long, even though it didn’t have much of a scientific basis.
How much we know now about animal cognition and animal emotions is uncomfortable for some people. It does mean we need to pay attention to how we treat animals.
With the coronavirus we have another interesting issue: how we eat wildlife. Ecologists and conservationists have been saying for fifty years that we shouldn’t be eating everything on the planet. Animal diseases can jump to humans with disastrous results. Turns out it might not be so good for us to treat animals like shit.
Some have argued that the move from a hunter-gatherer way of life to agriculture and the domestication of animals was the worst decision Homo sapiens ever made. It profoundly changed our relationship to animals. If you think about it, the hunter has respect for the animals he hunts. He knows how good they are at fighting back, how good they are at escaping; that you will never find them if they don’t want to be found. The farmer, in contrast, is in a dominant position and loses perspective. Small farmers may still be close to their animals and know them by name and so on, but on these big factory farms? No. Agriculture has not helped the human-animal relationship.
Leviton: We give a lot of attention to chimpanzees, but bonobos are just as close to us genetically. We share about 98.7 percent of our DNA with them. Some people find them more interesting to study.
De Waal: They are equally as relevant as chimpanzees, because they are equally close to us. You know, I’m partly responsible for making bonobos so popular. I described their sex lives, the way they make up after fights, and things like that. Still, there is a group of scientists who want to put the bonobos to the side, because the chimpanzee fits much better with their violent scenarios of human evolution. According to them, the history of humanity consists of eliminating others, killing the Neanderthals, conquering the world, being aggressive. If you build your whole evolutionary scenario on the proposition that humans are violent, males are dominant, and women barely matter, what do you do with bonobos, who are sex oriented and female dominated? They are just too peaceful, gentle, and matriarchal to fit into the myth of humans as “killer apes.” For example, female bonobos rub their genitals, their clitorises, together. I used to hear researchers say, “You call that ‘sex’? That’s just affectionate behavior.” I’d tell them, “If that’s not sex, try doing it in the middle of Times Square and see how fast you end up in jail!” [Laughs.]
Many female primatologists love bonobos. Among the general public, bonobos are popular especially with women and the LGBTQ community, and for good reason. But other researchers ignore bonobos and downplay the amount of cooperation in human societies. For example, Steven Pinker wrote a book called The Better Angels of Our Nature, in which he argues that humans have become less aggressive over time, thanks to civilization. That story makes sense only if we were very aggressive to begin with. To make his point, Pinker uses the chimpanzee as his main example of inherent primate behavior. He describes all the horrible things chimpanzees do to each other. He pushes bonobos aside because they don’t fit his story line. But if we started our theory of human development with bonobos, it would refute his scenario, because we’d be seen as inherently more peaceful and cooperative from the start.
It’s not all peace and love with bonobos, though. I recently went to Kinshasa, in the Democratic Republic of the Congo, to visit the biggest bonobo sanctuary in the world, Lola ya Bonobo. The name means “Paradise for Bonobos” in the Lingala language. All the groups there are dominated by an alpha female. You might think these females would be pleasant and nice, but they are very strict. They punish bonobos who don’t act right. The males have a hard time and will get away to a different part of the sanctuary if the females are not in a good mood.
Leviton: What does it mean to call a primate an “alpha”? Does it differ from the way the term is used in popular culture?
De Waal: The phrase “alpha male” was introduced for wolves by Rudolph Schenkel, a Swiss ethologist, in the 1940s. In my book Chimpanzee Politics, I describe alpha males as leaders who keep the group together, keep the peace, and build alliances. They are empathic and often act as the “consoler-in-chief,” interceding in fights and sticking up for the underdogs.
Now, in the business world, we see all these books about how to be an alpha male: basically, how to beat up your opponents, how to make them feel you are the boss, and how to attract women (who supposedly flock to these types). I sometimes speak to business groups and have to remind them that an alpha male or alpha female can have many different personality types. They can be bullies or coalition-building experts. They are not always the strongest physically. In my TED Talk about this, I speak about the chimpanzee Amos, an alpha male who got sick. He was liked by the other chimps, and while he was ailing, they brought him food and propped him up with the material they used to make nests. They respected him even when he was vulnerable and his days as the alpha were coming to an end.
Not all alpha males have such an easy time of it. They might be violently deposed. That’s one of the costs of being the alpha: others want your position. Sometimes we see old males who are no longer the alpha but still have considerable power behind the scenes, so to speak.
Chimpanzees who want to overthrow an alpha often become very generous in the months before their big move. To gain support within the group, they begin to tickle the infants, even though they’re not usually interested in them. It’s like politicians who kiss babies during the campaign.
Leviton: The chimp you named Mama was a very successful alpha female.
De Waal: Yes, for forty years she was the queen of the Royal Burgers’ Zoo colony in Arnhem, the Netherlands. My book Mama’s Last Hug is partly a tribute to how extraordinary she was. It’s true the males always dominate in chimpanzee colonies, but I make a distinction between dominance and power. You can have greater physical strength, but that doesn’t mean you have more power. The physically biggest male may not have the skills to be the alpha. He might not make the right friends or cut the right deals. Mama had much more power than many of the succession of alpha males who came and went during her time there. She and the oldest male — who was not the alpha — basically ran the group for decades. You might see this in an office: everyone knows who the bosses are, but one of their secretaries makes most day-to-day decisions. This is why I describe a chimpanzee colony as having “politics.”
Leviton: You coined the word anthropodenial, which is the opposite of anthropomorphism.
De Waal: I developed the word because anthropomorphism had become the insult of choice aimed at people like me, who talk about animal cognition and emotions. If I said a dog showed jealousy, they’d say, “Don’t be anthropomorphic. You’re always ascribing human traits to animals. Your dog cannot be ‘jealous’ — that’s a human term.” I always felt that, for apes, anthropomorphism is irrelevant. They are obviously human-like in their behavior, their anatomy, their brain structure. I don’t see the issue with using human terminology to describe them. So I had to find a counterword, to describe many scientists who were in denial about the similarities between species.
Psychology has really changed, though. Neuroscience has shown that the brain of a rat and the brain of a human have similar qualities. So psychologists have shifted their position.
But anthropology still emphasizes human specialness. Anthropologists hold meetings about what makes humans unique — they use the word successful, as in “Why are humans the most successful species on earth?” They don’t say “superior” because that word has negative associations now, but successful means pretty much the same thing. I don’t think humans are so successful, by the way. We’re destroying the planet.
Leviton: Is this connected to why you don’t like to call other animals “nonhuman”?
De Waal: I’ve never liked that word, as if they are unfortunate creatures who have the bad luck to be not human — as if we are the center of the universe. Why not refer to ourselves as “nonelephant”? [Laughs.]