Richard Wrangham: Violence, Sex, and Fire in Human Evolution | Lex Fridman Podcast #229

1. 0:00 – 0:49

   Introduction

   1. LFLex Fridman0:00

      The following is a conversation with Richard Wrangham, a biological anthropologist at Harvard specializing in the study of primates and the evolution of violence, sex, cooking, culture, and other aspects of ape and human behavior at the individual and societal level. He began his career over four decades ago working with Jane Goodall in studying the behavior of chimps, and since then, has done a lot of seminal work on human evolution and has proposed several theories for the roles of fire and violence in the evolution of us hairless apes, otherwise known as Homo sapiens. This is the Lex Fridman Podcast. To support it, please check out our sponsors in the description. And now, here's my conversation with Richard Wrangham.

2. 0:49 – 20:21

   Violence in humans vs violence in chimps

   1. LFLex Fridman0:50

      You've said that we are much less violent than our close living relatives, the chimps. Can you elaborate on this point of, uh, how violent we are and how violent our evolutionary relatives are?

   2. RWRichard Wrangham1:04

      Well, I haven't said exactly that we're less violent than chimps. What I've said is that there are two kinds of violence. One stems from proactive aggression, and the other stems from reactive aggression.

   3. LFLex Fridman1:15

      Mm-hmm.

   4. RWRichard Wrangham1:15

      Proactive aggression is planned aggression. Reactive aggression is impulsive, defensive. It's reactive because, uh, it takes place in seconds after the threat. And the thing that is really striking about humans compared to our close relatives is the great reduction in the degree of, of reactive aggression. So we are far less violent than chimps, uh, when prompted by some relatively minor threat within our own society. And the way I judge that is, um, with not super satisfactory data, but, uh, the, uh, the study which is particularly striking is one of, uh, people living as, um, hunter-gatherers in a really, um, upsetting kind of environment, namely, um, people in Australia, uh, living in, uh, a place where they've got a lot of alcohol abuse, uh, there's a lot of domestic violence. Uh, it's all, uh, a sort of a, a, a society that is, um, you know, as bad from the point of view of violence as, uh, an ordinary society can get. Uh, there's excellent data on the frequency with which people actually have physical violence and hit each other, and we can compare that to, uh, data from several different sites comparing, uh, we're looking at chimpanzee and bonobo violence.

   5. LFLex Fridman2:49

      Mm-hmm.

   6. RWRichard Wrangham2:50

      And the, uh, difference is, uh, between two and three orders of magnitude. The frequency with which chimps and bonobos hit each other, chase each other, charge each other, uh, physically engage is, uh, somewhere between 500 and 1,000 times, uh, higher than in humans.

   7. LFLex Fridman3:07

      Mm-hmm.

   8. RWRichard Wrangham3:08

      So there's something just amazing about us. And, you know, this has been recognized for, for centuries. Uh, Aristotle drew attention to the fact that we behave in many ways like domesticated animals because we're so un-violent. But, you know, people say, "Well, what about, you know, the hideous engagements of the 20th century, the first and second World War and, and, and much else besides?" And, uh, that is all proactive violence. You know, all of that is, is gangs of people, um, making deliberate decisions to go off and attack in circumstances which ideally, uh, the attackers are going to be able to make their kills and then get out of there. Uh, in other words, not, uh, face confrontation. That's the ordinary way that armies try and work. And, um, and there, it turns out that, uh, humans and chimpanzees are in a very similar kind of state. That is to say if you look at the, the rate of death from chimpanzees conducting proactive coalitionary violence, uh, it's, uh, very similar in many ways to what you see in humans. So we're not down-regulated with proactive violence. It's just this reactive violence that is strikingly reduced in humans.

   9. LFLex Fridman4:29

      So chimpanzees also practice kind of tribal warfare.

   10. RWRichard Wrangham4:34

       Indeed they do. Yeah. Uh, so this was discovered first in 1974. It was observed first in 1974, um, which was about the time that, um, the first, uh, major study of chimpanzees in the wild by Jane Goodall, uh, had been going for, uh, something like five years, uh, during o- of, um, the chimpanzees being observed wherever they went.

   11. LFLex Fridman5:01

       Mm-hmm.

   12. RWRichard Wrangham5:02

       Uh, until then, they'd been observed at a feeding station where Jane was luring them in to, um, to be observed by seeing bananas, which is great, and she had learnt a lot. But she didn't learn what was happening at the edges of their ranges.

   13. LFLex Fridman5:17

       Mm-hmm.

   14. RWRichard Wrangham5:18

       So five years later, um, it became, uh, very obvious that there was hostile relationships between groups, and those hostile relationships sometimes take the form of the kind of hostile relationships that you see in many animals, which is a bunch of, um, uh, uh, chimps in this case, uh, shouting, uh, at a bunch of other chimps, uh, on their borders. But dramatically, in addition to that, there is a second kind of interaction, and that is when a, uh, a party of chimpanzees makes a, uh, deliberate venture, uh, to the edge of their territory...... silently, and then search for members of neighboring groups. And what they're searching for is a lone individual. So I've been with chimps when they've heard a lone individual under these circumstances, or what they think is a lone one, and they touch each other and look at each other and then charge forward, very excited. Um, and then while they're charging, all of a sudden the place where they heard a lone call erupts with a volley of calls.

   15. LFLex Fridman6:37

       Mm-hmm.

   16. RWRichard Wrangham6:37

       It was just one calling out of a larger party.

   17. LFLex Fridman6:40

       Mm-hmm.

   18. RWRichard Wrangham6:40

       And our chimps put on the brakes and scoot back for safety-

   19. LFLex Fridman6:45

       Mm-hmm.

   20. RWRichard Wrangham6:45

       ... into their own territory. But if in fact they do find a lone individual and they, they can sneak up to 'em, then they make a deliberate attack, uh, they're hunting, they're stalking and hunting and, and then they impose terrible damage which typically ends in a kill straight away, but it might end up with the victim, um, so damaged that they'll, they'll crawl away and die a few days or hours later. So that was a very dramatic discovery because it really made people realize for the first time that Konrad Lorenz had been wrong when, in the 1960s in his famous book On Aggression, he said warfare is restricted to humans. Animals do not deliberately kill each other.

   21. LFLex Fridman7:32

       Mm-hmm.

   22. RWRichard Wrangham7:33

       Well, now we know that actually there's a bunch of animals that deliberately kill each other, and they always do so under essentially the same circumstances, which is when they feel safe doing it. So humans feel safe doing it when they got a weapon.

   23. LFLex Fridman7:46

       Mm-hmm.

   24. RWRichard Wrangham7:48

       Uh, animals feel safe when they have a coalition.

   25. LFLex Fridman7:51

       Mm-hmm.

   26. RWRichard Wrangham7:52

       A coalition that has overwhelming power compared to the victim. And so wolves will do that and lions will do that and hyenas will do that and chimpanzees will do it and, and humans do it too.

   27. LFLex Fridman8:05

       Can they pull themselves into something that looks more like a symmetric war as opposed to an asymmetric one? So accidentally engaging on the lone individual and getting themselves into trouble? Or are they more aggressive in avoiding these kinds of battles?

   28. RWRichard Wrangham8:21

       No. They're very, very keen to avoid those kinds of battles, but occasionally, uh, they can make a mistake. Um, but so far, uh, there have been no observations of anything like a battle in which both sides maintain themselves. And, uh, I think you can very confidently say that overwhelmingly what happens is that if they discover that there's several individuals on the other side, then both sides retreat.

   29. LFLex Fridman8:47

       Mm-hmm.

   30. RWRichard Wrangham8:48

       Nobody wants to get hurt. What they wanna do is to hurt others.
3. 20:21 – 39:16

   Study of violence in chimps

   1. RWRichard Wrangham20:21

   2. LFLex Fridman20:21

      When did your interest in this one particular aspects of chimp come to be, which is violence? When did the study of violence in chimps, uh, become something you were deeply interested in?

   3. RWRichard Wrangham20:35

      Well, um, for my PhD, in the early 1970s, I was in Gombe with Jane Goodall and was studying feeding behavior.

   4. LFLex Fridman20:45

      Mm-hmm.

   5. RWRichard Wrangham20:46

      But during that time, we were seeing, and I say, uh, we because there were, uh, half a dozen research students, uh, all, uh, in her camp. Um, we were discovering that, uh, chimps had this capacity for, for violence. Um, the first kill happened during that time, which was of an infant in a neighboring group. Um, and, uh, we were starting to see these, uh, hunting expeditions. And this was, uh, the start of my interest because it was such chilling evidence of, uh, an extraordinary similarity between chimps and humans. Now, at that time, we didn't know very much about how chimpanzees and humans were related. Chimps, gorillas, bonobos are all three big, black hairy things that live in the African forests and, uh, eat fruits and, and leaves when they can't find fruits, and walk on their knuckles. And they all look rather similar to each other, so they seem as though those three species, chimps and gorillas and bonobos, uh, should all be each other's closest relatives.

   6. LFLex Fridman21:59

      Mm-hmm.

   7. RWRichard Wrangham21:59

      And humans are something rather separate.

   8. LFLex Fridman22:01

      Mm-hmm.

   9. RWRichard Wrangham22:01

      And so, any of them wouldn't be of interest to us.

   10. LFLex Fridman22:03

       Mm-hmm.

   11. RWRichard Wrangham22:04

       Subsequently, we learn that actually that's not true, and that there's a special relationship between humans and chimpanzees. But at the time, even without knowing that, it was obvious that there was something very odd about chimpanzees, because Jane had discovered they were making tools. She had seen that they were hunting meat. She had seen that they were sharing the meat among each other. She had seen that the societies were dominated politically by males-

   12. LFLex Fridman22:37

       Mm-hmm.

   13. RWRichard Wrangham22:37

       ... coalitions of males. All of these things, of course, resonate so closely with humans.

   14. LFLex Fridman22:42

       Mm-hmm.

   15. RWRichard Wrangham22:43

       And then it turns out that, in contrast to conventional wisdom at the time, uh, that chimpanzees were capable of hunting and killing members of neighboring groups. Well, at that point, the similarities between chimps and humans become less a matter of sort of, you know, sheer intellectual fascination than something that has a really deep meaning about our understanding of ourselves. I mean, until then, you can cheerfully think of humans as a species apart from the rest of nature-

   16. LFLex Fridman23:22

       Mm-hmm.

   17. RWRichard Wrangham23:22

       ... because we are so peculiar. But when it turns out that, as it turns out, one of our two closest relatives has got these features that we share, and that one of the features is something that is the most horrendous, as well as fascinating, aspect of human behavior, then, you know, how can you resist just, you know, trying to find out what's going on?

   18. LFLex Fridman23:50

       So, I have to say this. I'm not sure if you're familiar with the man, but fans of this podcast are, so... We're talking about chimps. We're talking about violence. My now-friend, Mr. Joe Rogan, is a big fan of those things. I'm a big fan of these topics. I think a lot of people are, are fascinated by these topics. So, as you're saying, why do we find the exploration of violence in the relations between chimps so interesting? What can they teach us about ourselves?

   19. RWRichard Wrangham24:26

       Until we had this information about chimpanzees, it was possible to believe that, uh, the psychology behind warfare was totally the result of some kind of, um, cultural, recent cultural innovation-

   20. LFLex Fridman24:48

       Right.

   21. RWRichard Wrangham24:49

       ... that had nothing to do with our biology, or if you like, that it's got something to do with, um, uh, sin and, and-

   22. LFLex Fridman24:57

       Right.

   23. RWRichard Wrangham24:57

       ... God and the devil and that sort of thing. But what the chimps tell us, after we think carefully about it, is that it seems undoubtedly the case that our evolutionary psychology has given us the same kind of attitude towards violence as, as occurred in chimpanzees, and in both species, uh, it has evolved because of its, uh, evolutionary significance. In other words, because it's been, uh, helpful to the individuals who have practiced it. And, uh, now we know that, uh, as I mentioned, other species do this as well. In fact, you know, wolves, um, which (laughs) this is, this is really a kind of ironical observation, uh, Konrad Lorenz, who I mentioned had been the person who thought that human aggression in the form of killing members of your own species was unique to our species, he was a great fan of wolves. He studied wolves, and in captivity, he noted that wolves are very unlikely to harm each other in, um, uh, spats, uh, among members of the same group. What happens is that one of them will roll over and present their neck, much as you see in a dog park nowadays, and, uh, and the other, uh, might put their jaws on the neck, but will not bite.

   24. LFLex Fridman26:26

       Mm-hmm.

   25. RWRichard Wrangham26:27

       Okay, so now it turns out that if you study wolves in the wild, then neighboring packs often go hunting for each other.

   26. LFLex Fridman26:36

       Mm-hmm.

   27. RWRichard Wrangham26:36

       They are in fierce competition, and, uh, as much as 50% of the mortality of wolves is due to being killed by other wolves.

   28. LFLex Fridman26:46

       Wow.

   29. RWRichard Wrangham26:46

       Adult mortality.

   30. LFLex Fridman26:47

       Wow.
4. 39:16 – 1:35:45

   Human evolution and violence

   1. LFLex Fridman39:16

      So if we look at the big picture, what role has violence, or do you think violence has played in the evolution of homo sapiens? So we are quite an intelligent, quite a beautiful particular little branch on the evolutionary tree. Um, what part of that was played by, um, our tendency to be violent?

   2. RWRichard Wrangham39:41

      Well, I think that violence was responsible for creating homo sapiens. Um, and that raises the question of what homo sapiens is.

   3. LFLex Fridman39:55

      (laughs) Yes. Yeah, exactly.

   4. RWRichard Wrangham39:58

      So, you know, nowadays people, um, begin the- the sort of concept of what, what homo sapiens is by, uh, thinking about features that are very obviously different from all of the other species of homo.

   5. LFLex Fridman40:14

      Mm-hmm.

   6. RWRichard Wrangham40:15

      Uh, and, uh, our, our large brain, our, uh, uh, very rounded cranium, our relatively small face. Uh, these are characteristics which are developed in a relatively modern way by about 100 and, um, 70,000 years ago. So, you know, it's one of the earliest skulls in, in Africa that really captures that. But, uh, it has been argued that that is a, um, an episode in a process that has been, uh, started, uh, substantially earlier, and there's no doubt that that's true. You know, homo sapiens is a species that has been changing pretty continuously throughout the length of time it's there, and it goes back to 300,000 years ago.

   7. LFLex Fridman41:02

      Mm-hmm.

   8. RWRichard Wrangham41:03

      Uh, 315 literally is the, is the, uh, time the, the best estimate of a date for, uh, a series of bones from Morocco-

   9. LFLex Fridman41:12

      Mm-hmm.

   10. RWRichard Wrangham41:13

       ... that have been dated, uh, three or four years ago, uh, at that time, and have been characterized as earliest homo sapiens. Now at that point, uh, they are only beginning the trend of sapiensization, and that trend consists basically of gracilization of making, uh, our ancestors less robust. Um, shorter faces, smaller teeth, a smaller brow ridge, a narrower face, um, a thinner, uh, cranium. All these things that are, um, associated with, um, reduced violence. Okay, so that's, that's saying what... that's homo sapiens beginning. So it began sometime 3, 3 to 400,000 years ago because by 315,000 years ago, you've already got something recognizable.

   11. LFLex Fridman42:03

       So you're, you're more on that side of things that there was this gradual process. It's not 150, 170,000 years ago. It's, it started like 400,000 years ago, and it's just...

   12. RWRichard Wrangham42:14

       It started 3 to 400,000 years ago. And, and if you look at 170, it's got even more like us, and then if you- you look at, at, uh, 100, it's got more like us again, and if you look at 50, it's more like us again.

   13. LFLex Fridman42:25

       Mm-hmm.

   14. RWRichard Wrangham42:25

       It's all the way, it's just getting more and more like the moderns. So the question is, what happened between 3 and 400,000 years ago to produce homo sapiens?

   15. LFLex Fridman42:33

       Mm-hmm.

   16. RWRichard Wrangham42:34

       And, uh, I think we have a pretty good answer now.... and the answer comes from violence, and the story begins by focusing on this question: Why is it that in the human species we are unique among all primates in not having an alpha male in any group, uh, in the sense that what we don't have is an alpha male who personally beats up-

   17. LFLex Fridman43:02

       Mm-hmm.

   18. RWRichard Wrangham43:02

       ... every other male? And the answer, uh, that, um, uh, has been, um, portrayed most, most, uh, richly by, uh, Christopher Boehm, and whose work I've elaborated on, uh, is that, uh, only in humans do you have a system by which any male who tries to bully others and become the alpha, equivalent to an alpha gorilla or an alpha chimpanzee or an alpha bonobo or an alpha baboon or anything like that, any male who tries to do that i- in humans gets taken down by a coalition of beta males.

   19. LFLex Fridman43:44

       Mm-hmm.

   20. RWRichard Wrangham43:46

       Um, that coalition-

   21. LFLex Fridman43:48

       Yes. That's a really good, uh, picture of human society, yes. (laughs) I like it.

   22. RWRichard Wrangham43:52

       Okay. So, and that's the way all our societies work now-

   23. LFLex Fridman43:55

       Yes.

   24. RWRichard Wrangham43:56

       ... um, because, y- individuals try and be alpha, and then they get taken out, if-

   25. LFLex Fridman44:00

       Yeah. I mean, we don't usually think of ourselves as beta males, but yes, I, I suppose, (laughs) I suppose that's what democracy is.

   26. RWRichard Wrangham44:06

       Exactly. Yes. Exactly.

   27. LFLex Fridman44:08

       (laughs)

   28. RWRichard Wrangham44:09

       Um, okay, so, well, so, so at some point, alpha males get taken out. Well, what alpha males are, are males who respond with high reactive violence to any challenge to their status.

   29. LFLex Fridman44:22

       Mm-hmm.

   30. RWRichard Wrangham44:22

       You see it all the time in, in primates. Some beta male thinks he's getting strong and, and, uh, you know, maturing in, in wisdom and so on, and, uh, he refuses to, uh, kowtow to the alpha male. And the alpha male comes straight in and, and, uh, charges at him. Or maybe he'll just wait for a few minutes or... and then take an opportunity to attack him.
5. 1:35:45 – 1:48:02

   The Goodness Paradox and Catching Fire

   1. RWRichard Wrangham1:35:45

   2. LFLex Fridman1:35:45

      What is your book titled Goodness Paradox? What are the main ideas in this book?

   3. RWRichard Wrangham1:35:50

      Well, the paradox is the fact that humans, uh, show, uh, extremes in bo- in relationship to both violence and non-violence.

   4. LFLex Fridman1:35:59

      Mm-hmm.

   5. RWRichard Wrangham1:36:00

      And the violence is that we are one of these few animals in which, uh, we, uh, use coalitionary proactive violence to kill members of our own species, and we do it in large numbers, just like a few other species. And the, uh, non-violence is we're particularly extreme in, uh, how repressed we are in terms of reactive violence. And I, I told you the story of, of how we get there. You know, so what's so extraordinary about this is that, um, most animals, uh, are either high on both or relatively low on both. Uh, so chimpanzees are high on proactive violence and reactive violence. Bonobos are less, uh, than chimpanzees on both of those, but still hundreds of times more, um, reactively aggressive than, than humans are. What we've done is retain, uh, proactive violence being high and got, uh, reactive violence really being low. And so we have these wonderful societies in which we're all so incredibly nice to each other and tolerant and calm and, and can meet strangers and have no problem about, um, uh, be, leading to any kind of, uh, conflict, at the same time as, uh, we are one of the worst, uh, killing, uh, machine species, uh, that has ever existed. So what's so extraordinary about this is that if you look at the political philosophers of the last few hundred years, you've got this fight famously between Thomas Hobbes and Jean-Jacques Rousseau. Or literally you've got the fight between their followers.

   6. LFLex Fridman1:37:37

      Mm-hmm.

   7. RWRichard Wrangham1:37:38

      You know, so the followers of Hobbes say, "Well, Hobbes was right because he says that we are naturally violent and you need a leviathan, a, a sort of central government, uh, or a king, to be able to suppress the violence. So we're naturally horrid and, uh, we can learn to be good." Whereas Jean-Jacques Rousseau...... is interpreted as saying the opposite, that, uh, we are naturally good and it's only when culture intervenes and, and horrid ide- ideologies come in that we become uncivilized. And so people have, have had this endless fight between, are we naturally corrupt or are we naturally, uh, kind?

   8. LFLex Fridman1:38:16

      Mm-hmm.

   9. RWRichard Wrangham1:38:17

      And, and that has gone on, you know, for years, and it's only in the last two or three decades that anthropologists like Christopher Boehm and Bruce Knift have said, "Look, you know, it's obvious what the answer is. We are both of these things." And what is so exciting now is that I think we can understand why we are both. And the answer is, we come from ancestors that were elevated on proactive aggression, that were, uh, hunters and killers, um, both of animals and of each other. I think you've got to include that, you know, as almost certain, uh, from the past. And, um, and then now we've, we've taken our reactive aggression and we've down-regulated it, and that's given us power. It's given us power because once you get rid of the alpha male, once the beta males take over and force selection in favor of a more tolerant, less reactively aggressive individual, the effect is that our cultures suddenly become capable of focusing on things other than conflict. And so we have social groups in which individuals, instead of constantly being on edge in the way that chimpanzees are with each other, um, are able to interact in ways that enable them to share looking at a tool together, or share their food together, or pass ideas from one to the other, or support each other when they're ill, or whatever the issue is. Cooperate in ways that make the group far more effective. So you asked earlier, you know, what did I think about why sapiens was able to expand at the expense of Neanderthal so dramatically around 40,000 years ago. And the answer is, uh, that whatever it was, it had something to do with the sapiens' ability to cooperate. You know, that was the one gave them bigger groups. That's what enabled them to, um, have a far more effective way of living, and I suspect it was to do with their weapons and, and military aspects. But even if it wasn't that, the, the, uh, greater cooperation that sapiens were showing, uh, would have been hugely important.

Episode duration: 2:35:21