Mr. de Waal, we humans have long viewed ourselves as different from animals, particularly when it comes to language and emotions, but your research has highlighted deep similarities. What emotions have you found in animals?
I don't really see any emotions in humans that animals don't have. Emotions are a bit like bodily organs. I don't have any organ in my body that you don't find in a dog. You find similar organs, like a kidney and heart and lungs, in a frog. So, in terms of organs, the human body is not unique at all and I look at emotions in the same way. I do not think there are distinct human emotions, except maybe spirituality. The most dominant theory is the Basic Emotion Theory which postulates six basic emotions. Psychologist Paul Ekman went around the world and asked people to rate facial expressions on photos and identified six expressions which everyone recognises: happiness, sadness, disgust, fear, surprise, and anger. He also postulated that we share these with other animals. He called all the other emotions secondary. In psychology secondary emotions are seen as uniquely human. They include emotions that are not facially expressed, like love. But research shows the dopamine system of attachment, which is probably similar to love, is found in rodents and other animals. Similarly hope and jealousy and shame, are all called secondary emotions but I think you can find examples of these in other species, though they may not be as developed as they are in humans.
Is it new to talk of “animal emotions”?
Darwin wrote a whole book about the expression of emotions in humans and animals. Then we went into what I consider the very dark period under the psychologist B. F. Skinner. He and his followers said we should never talk about the internal states of animals and actually applied the same rules to humans. We should never talk about internal states, only behaviour -- that's why they called them behaviourists. When I was a student you couldn't mention the word “emotion” in relation to animals. People talked of motivational systems. But what is a motivational system? I don’t know, probably an emotion! If you are talking about territorial defence, mating behaviour or mother-offspring attachment then I think you are actually talking about emotions.
Why do you think the mainstream was hesitant to acknowledge animal emotions? Are we afraid of challenging human exceptionalism?
Exceptionalism plays a role. Religion influences us by suggesting that we have souls and animals don't. That dualism remains to some degree. There are many people who accept evolution for all animals and humans – but only up to the neck. For them, the human mind is something else. But although the human brain is big, it is not special. There is no part of our brain that you won’t find in a monkey brain, but people still see it as distinct. This whole attitude is the biggest flaw of western philosophy. It has brought us the climate crisis and the Covid crisis. It has created a sense that we humans are not part of nature and that we are free to do whatever we want with the world. This dichotomy between humans and the rest of the natural world has no evidence to support it – in fact it has led us into a lot of trouble.
Why do animals have emotions? Is it to aid them functioning as a group or a herd?
Emotions serve a purpose. In that way they are similar to the organs in your body. Emotions are a bodily state that prepare you for action. For example, you see a predator and you go into a state of fear. The emotion of fear doesn't tell you exactly what you have to do, unlike an instinct. There are options: Predators may be very big and you may want to hide or flee. If the predator isn't big, you may want to fight. You judge the situation, based on your experience as an animal or human, you know the best course of action. People think that animals are slaves to their emotions but that is not the case: all animals need to regulate their emotions. If you are a baboon and you’re in the middle of the hierarchy, you have to dominate and, on occasion punish, subordinate individuals, to tell them that you are the boss. But with dominant individuals you have to be very careful. You need to suppress behaviour like sexual or feeding behaviour in their presence.
“When I was a student you couldn’t mention the word ‘emotion’ in relation to animals”
Do all animals have emotions?
I assume that a chimpanzee has the same sort of feelings to me because the chimpanzee is a very similar animal with a very similar brain. But with an octopus or a fish, I have no idea if they feel the way I feel.
Do animals also show empathy or selflessness?
I've done a lot of studies on empathy. A typical expression of this is what we call consolation behaviour. There were studies into this with humans by psychologist Carolyn Zahn-Waxler where she would go into a family and ask a family member to cry and she described how young children, two years old, would go up to the person and touch their cheeks, and she called that an act of empathy or consolation behaviour. When I saw her speak, I realised my chimps do this all the time! After a fight, young chimps come up to whoever was involved in the conflict and would embrace, kiss and groom them. I would say all animals have empathy responses, they are sensitive to the emotional state of someone else. We now even have a neuroscience of empathy in rodents. Altruistic behaviour is connected to empathy. There are studies of rats and mice helping each other. I think we should use the same terminology for animals as for humans, not least because we now know that the neurological processes behind it are very similar.
Your research into capuchin monkeys showed us that they have a highly tuned sense of fairness – famously illustrated by your experiment with two animals, where one was given a slice of cucumber, one a grape, for performing the same task. When one monkey realised its counterpart was being offered the tastier grape, it indignantly tossed its slice of cucumber back at the researcher. Were you surprised at this keen sense of unfairness?
Among monkeys, like the capuchins, there is resentment about getting less than someone else. That’s a basic form of the sense of fairness, which you find also in three or four-year-old children. Chimpanzees go further. The one who gets a grape may refuse the grape until the other individual also gets a grape. What happens in chimpanzees and adult humans is that we anticipate a negative result. For example, if I have a pizza and we are both hungry and I only give you a small slice and eat the rest, I know that you're going to be pissed off. If I want a good relationship with you, I should give you a substantial share. Since chimpanzees can think ahead, they also anticipate a negative reaction.
That particular grape/cucumber experiment went viral on YouTube. Why do you think it touched a nerve with us humans?
It's been seen around two hundred million times – it’s probably the most watched animal experiment on the Internet. It has touched a lot of people because they recognise the reaction. Physically the monkey is very similar to us, which means we empathise with it. At the moment in society we are very interested in income inequality and so this connects with the subject of the experiment. It struck me though that in the comment section, many people pity these monkeys, saying they are being experimented on all day and it is cruel. To correct that impression: These monkeys live in a group of 20 monkeys and they are only in our test area for half an hour at a time and they come in voluntarily. Before we send the two monkeys back to their group we give them handfuls of goodies because, of course, we want them to feel good and come back to take part in later tests.
Your latest book “Mama’s last hug” takes its name from the last hug given by “Mama”, a dying chimp, to her zoo keeper. Could you please describe the reaction to the film clip?
People have a very strong response to the video. It was on Dutch TV and people cried and were very moved by it. I understood that but I was also surprised at their surprise that Mama had such human-like expressions of emotion. For fifty years we have been saying that chimps are our closest relatives, so why would you be surprised that we express emotions in a similar way? Among camels, giraffes or dogs, expressions of emotions are different from ours. But among the primates, especially chimps, everything is very similar. We are basically apes.
Following the death of Mama, an important alpha female of the group, what could you observe about how animals grieve?
The zoo did something that some don't do: they gave the group access to Mama’s corpse, to help the apes realise she had died. It prompted a strong reaction: The males jumped on her and dragged her around, as if trying to revive her. This is something that we have observed in the wild as well. It is also something that we do in our own hospitals: when someone dies, we try to resuscitate them. The females had a gentler response, they would lift an arm and watch it drop or they would listen to her mouth, probably for signs of breath. There was one female which Mama had adopted as a baby and she was very protective of her mum's body and tried to stop these attempts of interfering with her. The females visited her and everyone went very silent, which is unusual for chimpanzees which are normally very noisy.
Mama was an alpha female. How do alpha male/ females exert their power? How do they differ?
Mama, for example, was an alpha female for 40 years, which is unusual. Males, for example, rarely go over five years in their alpha position. She was alpha female for so long and had an enormous amount of power. The female hierarchy is separate from the male hierarchy and that's the same among all primates. Females care about where they rank among the females and males care about where they rank among the males. Even in a group of baboons, where the males are twice the size of the females, the alpha female is a very important position. It is basically a female society where the males come and go. The female hierarchy is generally more stable than the male’s. An alpha male needs to be a sturdy and strong, not necessarily the biggest, but healthy and vigorous. Females are different. Mama was still the alpha female even when she barely could walk and was practically blind. Among females, age is actually a plus.
You have lived in America for many years. Do you observe classic chimp behaviour in politics?
I have seen alpha male chimpanzees lose their position of power. Their first reaction is a tantrum, almost like a baby whose mother rejects them from nursing. Then they go into a deep depression. I have seen that over here too, that inability to accept loss, then acting as if it is the biggest insult ever. Also you can see body language parallels. In the previous election, when Trump was surrounded by 12 or more contenders from the Republican Party, he tried to intimidate them, making himself big, lowering his voice, insulting them. All of this is very chimp like.
What can we learn from chimps?
Chimps are much more honest as politicians than humans are. They want power and they work for that, especially the males. They don't have ulterior motives or say that they want to help the country or the economy. Human politicians, of course, would not be going through all this mudslinging if they did not have the higher motivation of power but they never talk about it. In that sense, I think chimps are much more honest and preferable to human politicians.
Interview by Jess Smee