When Monkeys Make Up – Chimps are from Mars, bonobos are from Venus.

Posted on 09/01/08

"I never planned to become a savanna baboon when I grew up; instead, I had always assumed I would become a mountain gorilla,” writes Robert Sapolsky in his delightful autobiography, A Primate’s Memoir: A Neuroscientist’s Unconventional Life Among the Baboons. It tells the story of Sapolsky’s three decades of field work in East Africa, where he studies stress among the members of a tribe of baboons. Baboons don’t willingly come in for a cholesterol test, so the job includes tranquilizing them with a blowgun. A review in Outside magazine called the book “a powerful meditation on the biological origins of baboon and human misery, as well as a naturalist’s coming-of-age story comparable to Jane Goodall’s and E. O. Wilson’s.” In addition to being an honorary member of the tribe, Sapolsky is a professor of biology and neurology at Stanford University and the recipient of a MacArthur Foundation genius grant. Like Michael McCullough, who talks about revenge on page 20, Sapolsky puts forward the idea that reconciliation is more likely to occur when the relationship of the two parties is highly valued.

IC: A lot of work is being done with primates and forgiveness. Could you give us an overview of this research?

Sapolsky: There is this whole hot subject of reconciliation in primatology. The definition of reconciliation is that after two animals have had a fight with each other, over the next ten minutes or an hour or so, there is a higher-than-expected rate of their doing something nice and affiliative, such as grooming each other. This has been observed in about twenty-five different species, including most of the apes. I don’t study it in baboons because my beasts never forgive each other. You see reconciliation with female baboons, but male baboons never reconcile. For a bunch of reasons, I only study male baboons. There is nothing that looks like forgiveness among them.

Some primates are miserably aggressive to the point of murder. Chimpanzees will kill each other. In addition to evolving that, they also evolve a system that says: Enough. It’s over, let’s move on. It’s time for some version of reconciliation and it’s now called reconciliative behavior. Certain individuals have a higher rate of making up than was expected — grooming each other, things like that. What’s fascinating is that it’s not just random. There is a pattern that looks perfectly human, which is that not everybody reconciles with each other, but some pairings are more likely to reconcile.

What we are seeing is that the more valuable your relationship with the other animal, the more likely you are to make up afterwards. This was shown in a brilliant study written by a researcher named Marina Cords at Columbia University. She took some macaque monkeys, captive ones, and devised two different situations. Under one the animals were in two separate cages next to each other and had to individually carry out a task in order to get a food reward. The other scenario was that they had to do a cooperative task instead. What she showed was that the ease of cooperation, when the pair had worked together on a regular basis, made them more likely to reconcile after tension. This is akin to saying, “Whoa, he and I go back thirty years to kindergarten, and we’ve got a good working relationship. It’s probably worth it to work this out, to get past the tension.”

It’s interesting that they make up more with members of their own troops, not enemy troops. Can you elaborate on that phenomenon?

There’s a certain logic in that on one level, a strictly utilitarian level, it’s easier to reconcile with animals inside your troop because these are the ones you’re possibly having stable, cooperative relationships with; and on an emotional level, these are the animals you know. They’re familiar to you. Virtually by definition any baboon on the other side of the river, whom you don’t know, is a scary Other. So that’s going to be a lot harder to do.

What about gender differences in reconciliation?

In my world of baboons, females reconcile, males don’t. And what that may have to do with is almost by definition female relationships with any other female in the troop are always more valuable than almost any male’s relationship with another male. How come? Because at puberty, many males pick up and leave their home troop and join some other troop. Females spend their whole lives in the same troop. So every adult female has known every other adult female her entire life. They have a long history together and that means they have more incentive to make things stable.

Is Frans de Waal, the Dutch-born primatologist now at Emory University, the big man on campus for the study of primates and reconciliation?

He is the person who first used the term reconciliation and demonstrated it among non-human primates. One can say, as I would, that he is one of the best and most creative primatologists in the universe. What he has focused on is — number one — that primate societies have this ability to reconcile in some circumstances. Number two is that the old, philosophically Hobbesian, view of humans as intrinsically miserable and violent to each other under a thin veneer of civility supplied by society is complete nonsense. The evolutionary roots of altruism and cooperation and even things that look like empathy are there in lots of closely related species.

I guess the third important thing is that he is the only person out there who is an expert on both the behavior of chimpanzees and a closely related species called bonobos. You can’t get two more different species on earth. Chimpanzees are violent, stratified, and male-dominated. They kill each other and cannibalize each other’s babies. They have something that looks like warfare. Meanwhile, bonobos are female-dominated and have extremely low rates of aggression. They solve every tension on earth with sex. The sound bite is: “Chimps are from Mars, bonobos are from Venus.” What you then deal with is: Who is our closer relative? What’s in our genes? What’s constantly emphasized is that we share approximately 98 percent of our DNA with chimps. What de Waal hones in on is that we also share about 98 percent with bonobos. There is as much rationale in thinking that the bonobo is our closest relative. There is not a leg to stand on saying that we have a long evolutionary legacy built into us for violence, stratification, or any of that mean, nasty stuff.

How do primates reconcile, other than grooming each other?

I think that’s about it. They are impressive and clever but, at some point, they aren’t human. Grooming is basically their range. Grooming is the glue that holds a primate social group together. It’s sort of the equivalent of social gossiping. Everybody just sits around and grooms each other. In a baboon group, if something scary happens such as they’ve just stumbled into a lion, everybody scrambles. Once the coast is clear, they all come down from the trees and sit in a close group and groom each other for the next half hour. It’s how they make each other feel better.

Does any of the research suggest to you that it is natural or inborn that human beings apologize?

Again, it’s sort of this punch line — we may be related to some species that reconcile like crazy. And then we may be related to species that don’t do that. At the end of the day, we’re not chimps, and we’re not bonobos, and we’re not baboons. We’re close relatives, but we solved our own evolutionary problems. Given that, I would say that, as a species, we have an equal tendency toward being affiliative and reconciling and being miserable to each other. We are neither by our intrinsic nature. What we are is just tremendously sensitive to social context. It’s not that, oh, we’re inevitably like this or that. If you construct the sort of world that facilitates violence, we are a violent species. You construct a world where the context is one of compassion and affiliation, and we do just fine in that direction. We don’t have an inevitable tilt towards either. In other words, what our genetic legacy indicates is that, if you want to fix some of these problems, they aren’t going to be fixed on the genetic level — they are going to be fixed on the environmental level.

We human beings often hold grudges that make true reconciliation difficult. Do other primates hold grudges?

Yes. They definitely do. Male baboons certainly do. Example: You get two guys who get into a fight. Baboons have a whole ritualistic way of saying, “That’s it. I give up. You won.” And the ritual shows that at that point it’s finished. Fight’s over and you go back to doing what you were doing. But what you’ll see is that with certain guys, with certain personalities, is that later that day, when it seems to be all over, this guy encounters the guy who started the fight and they give a relatively low-tension gesture to each other — basically, the first guy sticks his rear end in the other guy’s face, which is basically saying, “Everything is cool. We’re fine.” According to the rules, the other guy is supposed to sniff at his bottom. And it’s here that one of them slashes the other in the ass, totally breaking the rules. This certainly looks like a grudge to me. It’s not random who does it — it’s certain guys with certain personalities.

What happens to these grudge-bearing baboons?

These are the guys who might be loosely defined as those lacking in social intelligence. They are likely to slash one too many guys in the rear. Or they establish a pattern of doing that so that other males won’t form coalitions with them. One of the sound bites is that in the baboon world attaining high rank has everything to do with having big, sharp canines and being as aggressive as hell, while maintaining high rank has everything to do with social intelligence — which provocations you avoid and impulse control. So those guys who bear grudges aren’t going to do well in the long run. They are less likely to be able to stay in a high position. They are more likely to get that horrible, crippling injury or just burn out because they have burned lots of bridges along the way.

Do primates ever apologize and change their ways?

That’s very interesting. Every now and then you get a guy who goes through some sort of utterly mysterious epiphany and transformation. Once in a decade, you get a guy who’s high-ranking because he’s just an SOB who has to remind everybody of his high rank about eleventy times a day. And then something happens; he changes. He walks away from it, and he typically lives a long and uninjured life, doing affiliative stuff. But this is literally once a decade at best. You get a bunch of baboonologists together, and everybody knew a guy like this, and we talk about how much we loved him and how amazing he was. We wonder where this change came from.

Did you have a guy like that?

Yeah — a guy named Nat, Nathaniel, whom I kind of adored. I have his picture on my wall. He was at the top of the hierarchy. He was not so much a brutal alpha male, but he was a big, imposing, muscular guy who just scared the willies out of everybody. And then one day, he just picked up and walked away from it and spent the rest of his life hanging out with females and playing with their babies. I don’t know what happened in his head, but he was wonderful.

Did you ever meet a baboon you thought was just a lousy individual?

Over the years there were two guys who really stood out, and probably reflected in that I didn’t give either the nice Old Testament names that I really liked. One of them I called Nebuchadnezzar, and he was a complete creep. Every time anything upsetting in his world happened (which was often because he wound up being rather low-ranking because in his heart of hearts he was a coward), instead of picking on somebody his own size he’d find an adult female to take it out on. All he was about was giving ulcers to avoid getting them. He was a horrible animal. The other was a guy Nick, who was one of those mean, flinty, tough, leathery guys who wind up being very dominating. He rose to the top of the hierarchy, and he did things like ignore reconciliation signals at a point where any normal, decent baboon is supposed to say, “It’s over with, it’s done, hooray, I won.” Instead he would attack when the other animal was giving a submission signal. One of my favorite things he ever did, just in terms of how both sophisticated he was while being a creep, was when I had to dart another guy, Reuben, to anesthetize him because I needed to take blood samples. Darting can be pretty complicated. These are wild animals and they’re going to go down in the middle of the field where you are hoping that everybody else doesn’t freak out and try to rip you apart or, if he has lots of rivals, rip him apart. It’s a pretty hairy undertaking, and you try to do it in a circumstance where when he goes down, you’re going to get to him quickly. One day I darted Reuben, a high-ranking guy, and the worst possible thing happened — he picked up and ran down to this stream bed and passed out on the other side. I had to drive five minutes around the stream to get to him. Just as I rounded the bend, I spotted another baboon moving toward him very quickly. It was Nick. One of the reasons darting a baboon is so hairy is the fear that a rival might maul him during these vulnerable minutes. And here was Nick, barreling down on the semi-conscious Reuben. I was too far away to dart Nick. Then I saw Nick, slowly, forcefully placing a hand on Reuben’s shoulder and another on his haunch. Then Nick gave a loud, triumphant vocalization we call a wa-hoo call, so everyone in the troop can then twist around and look at what happened. And he does this, and then he marches away. I couldn’t believe it. The SOB was taking credit for my darting. But, as often happens to high-ranking guys, Nick eventually got a crippling injury and went down in a hail of bullets and spent a small amount of time as a low-ranking, very disliked guy in the troop before he picked up and tried his fortunes elsewhere, and I never saw him again.

One of the things I enjoyed in A Primate’s Memoir is that the characters, human and baboon, really came alive. I believe one reviewer might have gone so far as to compare the baboons to characters in Dickens! But is this an anthropomorphic way of viewing them, and is it something scientists do?

It’s certainly stuff they did eighty years ago, when it was a descriptive science and a much more emotional than intellectual one. And then as it turned into a real science, it became terribly embarrassing to do anything like talk about your animals’ emotions, let alone your emotions in response to your animals, and there’s no way to avoid the fact that these are animals. Close relatives, can have some similar feelings and evoke very strong ones in us. And some of the trendiest and most scientific words in the business these days are words like emotion or temperament when describing primate personality. This is not anthropomorphizing. You know, you do a certain amount of it just to make the ideas accessible, but it’s real science.

They’re close relatives, and they are close relatives emotionally. They are familiar, they can be anxious, depressed. They can be incredibly nice to each other and in a way that some evolutionary bio with a calculator and clipboard can turn into equations. But at the end of the day, these are animals with emotional systems that are very familiar.

Does primate research have implications for married couples?

Yes. If nothing else, baboons are not great communicators and are particularly lousy at expressing their feelings, except for rotten, vile, aggressive ones. But to the extent that grooming is a surrogate for communication, that’s important. Reconciliation is very important. In one of the sound bites — oh, a relationship is hard work — a relationship among non-human primates, if you’re going to have stable reciprocity, that takes work too. You’ve got to be willing to be the first one to do the reconciliative thing. I don’t know if somewhere in the head of a macaque is the notion, “I shouldn’t be the first to groom, because that’s admitting I was the one at fault.” That one’s not happening. But there is a certain equivalency in why it’s hard to take the first step. The very fact that it’s hard shows that it is worth it.