Primatologist Explains the 1% Difference Between Humans & Apes ｜ Richard Wrangham ｜ EP 249 (BAifu7lu8TU)

https://youtubetranscript.com/?v=BAifu7lu8TU

We only know two species on earth in which males live in groups often with their relatives and go out on raids to kill members of neighbouring communities. And those were chimpanzees and humans. Hello everyone. I’m very pleased to have today as a guest on my YouTube channel and podcast Dr. Richard Wrangham of Harvard University. He’s an anthropologist and primatologist and not only an anthropologist and primatologist but one of the top, certainly one of the top people in his field. I ran across Dr. Wrangham’s work back in 1996. He wrote a book with Dale Peterson, Demonic Males, very provocatively titled, a study of aggression in primates, including human beings, and an analysis as well of sex differences. And I learned an awful lot from that book. And since then he’s published two others, Catching Fire, How Cooking Made Us Human, also not a title that you would expect because it’s not as if people popularly think about cooking as something that made us human. So that was very interesting. It’s a great book. And then more recently, The Goodness Paradox, the strange relationship between virtue and violence and human evolution, which was published in 2019. Dr. Wrangham began his career with Jane Goodall studying chimpanzees in Gombe Stream National Park in Tanzania, Tanzania, and began an association there with Diane Fossey, another stellar primatologist who worked primarily with gorillas. He was then a professor at the University of Michigan and finally Ruth Moore, professor of biological anthropology at Harvard, where he is now. He’s also a MacArthur fellow, MacArthur fellow, which makes him a recipient of the prestigious prize, popularly known as the Genius Grant. And so we’re going to talk today about human evolution, primate evolution, aggression, the use of fire and all those things. And so welcome, Dr. Wrangham. Thank you very much for agreeing to talk with me today. Great to be here. Great to meet you. Yeah. Thank you. Thank you. So I didn’t know, or perhaps I’d forgotten until I looked into you again this week that you more or less began your career with Jane Goodall. And that’s pretty interesting. So do you want to walk us through your, how did your career develop? How did you develop an interest in primatology and anthropology? And maybe you could also define those fields for everyone. I love being in the wild. I love being in nature. As a kid, I liked bird watching. And that took me to more and more remote places. By the time I was 17, I spent nine months in Zambia in a national park in which it was called Kafui National Park. It had something like 20 people living in it. And together with its border areas, it was slightly larger than Switzerland. So it was a wonderful opportunity to really get a sense of what it’s like to live in the wild. And I went to Oxford University to read zoology as an undergraduate. And after that, I wrote to Jane Goodall and said, is there any chance of being able to work with her? And the reason was that I was just fascinated by animals that could serve as some kind of entry into thinking about the way in which our ancestors had adapted their behaviour to their own problems of life in the wild. So I’ve got two questions that stem from that. So what in the world were you doing living in that park when you were 17? And how did you manage that? And how did that come about? And then the next question is, why were you convinced or are you convinced now that the study of non-human animals is a useful means of shedding light on human behaviour? Two very different questions. So I told you I just love the wild. And I’d been on expeditions to more remote parts of Britain in my adolescence. But I saw the opportunity to do more. And I wrote, I don’t know, 100 letters to anyone whose address I could find saying, could I become a research assistant joining you in your field studies? And a guy called John Hanks, who ended up as a the chief conservation scientist for the World Wildlife Fund in South Africa, was doing studies of elephants and other things in Zambia. And he took me on. I was paid a shilling a day and just had the most incredible time. So what were your living conditions like in that particular at that particular time? Well, they were very civilized. I mean, I had a regular little cabin in a small sort of camp that was ultimately destined to become a tourist venue. It wasn’t really at that stage. It was a remote area. You had to drive a couple of hundred miles to get there. But of course, we did go camping. And so that was a major thrill, going camping in an area that was full of really wild animals and no opportunity to call for help, as it were. You’re really living on your own. So if you ran into wild animals, you had to know what to do. And in my first few weeks there, I went for a walk on an inadvisable area and found myself catching up on a rhino and was only stopped from bumping into it in thick vegetation by the arrival of well, I was lost and people were shooting rifles to tell me where to go. And so this is a little adventure for a 17-year-old learning about self-sufficiency in the wild. And you mentioned, were you studying elephants at that point? I was participating. I wasn’t studying anything myself. Right. And yes, so I mean, this was very dramatic stuff because we were trying out a new drug, which has since become a sort of standard drug for immobilizing animals, mammals in the wild. Immobilon, it is now called. But at that time, the delivery systems were poor and the doses were unknown. So we would walk up to elephants and John would fire a crossbow dart into the elephant and would then hope that the elephant would fall asleep so that we could take measurements, mark it, extract parasites and so on. And the amusing thing in retrospect about this is that when an elephant falls asleep, it stands absolutely solid. It doesn’t necessarily fall over. It’s like a table. Got four strong legs. And so then the question is, is it asleep? Seems like an important question. Well, exactly. So instead of all of us swarming up to it, one person, and I’m very happy to say that it wasn’t me, was deputed to go up and pull its tail. And since you didn’t know whether or not this is asleep or awake, I think this is very brave of John to do this, who took that upon himself. And so then it turned out that he always got it right. It was asleep. And then what we had to do was to get the elephant onto its side. And this involved four of us getting onto one side of it and pushing as hard as we could. But this only affected a sway. So the elephant would totter over, as it were, to the right side of who we were pushing on the left, and then it would sway back towards us. So we had to run backwards and then catch it again as it swayed further forwards and so on. I mean, you can see what a sort of thrill all this was for a young aspiring naturalist. It sounds like a study that would be very difficult to get through a research ethics committee. Yes, and rightly, actually, because in the previous year, the person in my position had been killed by elephants. So there were serious aspects to this. And we did have to take what precautions we could. Right. Yeah, well, I wasn’t necessarily saying that favourably. I mean, to gain knowledge requires a certain degree of risk. And I suspect that’s particularly true when you’re out in the wild, observing wild animals. That’s not something you can make 100% safe. I mean, obviously, you don’t want to be foolhardy. But there is the thrill of the adventure that goes along with that. That’s a necessary part of it, I think. Although, by the way, when a woman called Nancy Howell had her son killed while she was doing fieldwork in South Africa, or I think it might even Botswana, she did an analysis of deaths among anthropologists doing fieldwork and found that the major source of death was car accidents. Right, right. You know, the roads are bad. Right. Yes, well, in car accidents are a major killer everywhere. So maybe that’s a good rule of thumb for danger. If it’s safe, or if it’s no more dangerous than driving a car, which is something almost everyone accepts, maybe that’s safe enough. So, okay, so you got accustomed to this and you found that you liked it. You went back to Oxford and studied zoology. And then you wrote to Jane Goodall. I’ve got that timeline, correct? This was the late 1960s that I was studying zoology. And there were two writers whose work had really impinged on the public imagination at that time in relationship to human evolution. There was Robert Ardrey, a playwright who wrote a book called African Genesis and another called Territorial Imperative, in which he produced some bold sweeping ideas about how human competitiveness and conflict had arisen from our time when our ancestors were in Africa. And there was a Desmond Morris who wrote a book called Naked Ape, in which he emphasized in particular the sexual side of human evolution. And what those books did for me was to say that there was a world out there waiting to be explored of really understanding in a way that had not been attempted before, where humans come from in terms of our behavior. Simultaneously, this was a time when the discovery of the social structure of all sorts of large mammals was taking giant leaps forward. The main study that I was doing with John Hanks in 1967 in Zambia was a study of the behavioral ecology of an antelope called water buck. It’s a very widespread antelope. Behavioral ecology means understanding the social behavior in relationship to all the environmental pressures. This was the first such study done on water buck. No particular surprise because many of the first studies were being done at that time on animal animals, on lions and gorillas and many different things. So there was a sense of impending discovery and what happened even in the late 60s but particularly in the early 70s was the discovery of a lot of difference in the different species. Even quite closely related species might have not just differences in group size and flexibility but differences in their social relationships in what at first seemed totally mysterious ways. You know one species would have a society in which females all lived in the same group as that they were born in, would never leave and males would come in from outside around adolescence. Other species the opposite would happen. Some species would have females that readily mated every different male in the group. Others would have a society in which females would only mate with one male. All sorts of fascinating differences were emerging and hints were coming through about how you could explain these. So this was a very exciting moment because when you combine it with the opportunity to think about humans then we could get a long way beyond the kind of very naive political science interpretations of human behaviour. We could really embed it in the environment in which humans had evolved. So that’s a tricky issue you know because well one of the things your work highlights and this has been the case with other primatologists particularly more recently is that because you just mentioned that species that are even very closely related can have radical differences in their fundamental behaviours and you highlight the differences for example between bonobos and chimpanzees which are very closely related. So then you ask yourself well if bonobos and chimpanzees can be so biologically similar, structurally similar let’s say, but so behaviourally different, how is it that you decide what’s reasonably generalized to the human case and why should you believe that anything could be given? Right because there’s similarities and differences between all of the apes and so how do you prioritize the similarities versus the differences and how do you decide when you can draw conclusions that are more universal rather than local to that particular species? Yeah I mean this is the kind of stuff that we grapple with all the time of course and I think it’s quite a long story working out what we can say about humans in relationship to call it the other apes or the great apes. So we have a a very strange position as humans. It used to be thought when I started for instance in the 1970s it was fascinating to go and study the chimpanzees but they were just one species of great ape among the other main three gorillas, bonobos and orangutans that all seemed sort of roughly equally important for understanding human evolution. There was the apes and there was humans. An enormous shock happened in 1984. In 1984 two ornithologists at Yale, Cacone and Powell, published a paper in which they used techniques that they’d been applying to the study of the evolution of birds to the apes and humans and this technique was to assess the degree of similarity of DNA. So they’d worked out this DNA annealing system and they applied it to apes and humans and they claimed that chimpanzees and bonobos were the most closely related species and then chimpanzees bonobos and humans were more closely related to each other than any of them were to gorillas. So that kind of put us in the in the chimp category. Now let me ask you just there I want to ask you a question about that DNA technique. Now if I remember correctly the way that was done to begin with was to to take DNA from separate species and to heat it so that the it split apart and then to have the DNA from the different species joined together and then to assess how tightly bonded the DNA was to the to the between species and the the hypothesis was the more tightly bonded it was so the harder it was to pull apart once it regrouped the more closely related the species was. That was the first way of doing DNA similarity analysis. That’s been superseded but was that the 1984 work? Very good yes absolutely and the the technique was was a little crude. You know unzip things and zip them together and see how tough they are to pull apart and that crudeness meant that people could challenge the results and it took maybe a decade for people to become you know the the profession as a whole to become really convinced that these extraordinary results and the reason they seemed so extraordinary was because if you take the difference between a chimpanzee and a gorilla they look as if they’re very closely related they look so closely related because if you just imagine allowing a chimpanzee to just keep on growing it basically turns into a gorilla and many of the differences between gorillas and chimps can be understood just in terms of body size gorillas being bigger than chimps so when the argument is made that or actually you know it’s not an argument i mean just absolutely clear right now that that chimpanzees and humans are more closely related to each other than either is to a gorilla what that means is that the common ancestor of chimps and humans is very likely in the mold of the chimpanzee gorilla either either they’re the same very similar kind of animal which if it was very large would be like a gorilla if it was very small it would be like a chimpanzee either that or there’s been a fantastic degree of evolutionary convergence between some mysterious ancestor which have become more gorilla like and become more chimp like but no one thinks that that is the case right so so the idea is that and this is this is what how long ago did gorillas split from chimps hypothetically is that like 10 million years ago that sort of thing 10 million so so the common ancestor of chimps and gorillas and the chimps in this discussion include us roughly speaking so that’s 10 million years and then seven million years ago we split from chimps and the bonobos and the and the chimps split two million something like that or one or two million years ago yes right so maybe more like one nowadays they were still getting a increasingly confident assessment of that but anyway much more recently long after we had left the the chimpanzee bonobo line right and we might just also throw out the finding i suppose the hypothesis that homo sapiens sapiens that’s us that were about 300 000 years old in our current configuration something like that yes and in between we got the genus homo so the genus to which we belong and that emerged about two million years ago so so you you’ve got the common ancestor with chimps six or seven million years ago and then between then and two million years ago we had these animals that are rather like chimpanzees standing upright australopithecines and they gave rise to our genus homo about two million years ago and ever since then our ancestors have basically looked like us i basically in the sense that you could take the earliest homo homo true homo homo erectus and they could walk into a clothing store on main street and pick clothes off the peg and they wouldn’t they’d fit reasonably well they’d be you know they’d need the big size heavenly muscled but nevertheless right we can we can estimate the the the the difference the the we can estimate when we when these different species split from one another by looking at the degree of genetic difference and inferring the split from such things as divergent mutations because we know that mutations occur at a fairly standard rate is that is that and then there’s obviously fossil dating but what what other techniques are used to estimate the the divergence dates yeah the more recent times obviously we’ve got the fossils so you know we have a very good fossil record back to more than two million years ago and and we can be very confident that our ancestors were indeed homo erectus which as i say i mean was the first thing that was fully bipedal in the human style going back to two million years ago and then then we got a pretty good record but obviously the older you go the more broken it is but of the australopithecines and by the time we get to three four million years ago it’s getting increasingly broken but nevertheless there’s half a dozen different species and more that have been recognized in the african um habitats and uh and then by the time you’re asking the question about when it was that you have chimpanzees and humans as a common ancestor with a common ancestor there you do have to rely on genetic data as you say the rate at which mutations accumulate because we do not have any good fossil evidence for that animal and the reason for that is partly just is getting old and also probably because it would have left lived in a forest and forests don’t preserve bones well you know they tend to be too acid and the bones just decay very quickly but i bet eventually someone will find a pretty good you know something close to the the chimpanzee human common ancestor so 10 million years okay so let’s go back to the biography now you you you came out of africa you studied zoology you wrote to jane goodall and you told her about your experiences in africa so she knew that you could probably handle it why why and and by that time you had an undergraduate degree i did that’s right so you started working with her in where in in tanzania tanzania tanzania tanzania yes in 1970 yeah in 1970 so what was that like and what what was what was it like to work for her and and what did what were you what were you doing during that period of time for my first year i was a research assistant to her i was just learning the job and i would say that within about 20 minutes of seeing my first chimpanzee in the wild i recognized that there was a mind in that animal that was different from that of a waterbuck you know this is not just an antelope and it’s difficult to say exactly what’s going on you know but but there’s something about the use of eyes and something about you know the the way that they’re evidently concocting strategies that very rapidly tells you that you’re dealing with an animal that is like other animals but also is cognitively you know quite sophisticated and of course that makes it incredibly interesting now this is 1970 i said long before i had any kind of concept that we were looking at a good model of the human ancestor so this was just you know another ape but here’s what was so amazing you know i happened to arrive there at a time when some very fundamental discoveries were were being made jane goodall had already discovered that chimpanzees had very strong relationships among males very very brotherly very fraternal relationships somewhat recalling the kind of thing that you can see in i don’t know fraternities in contemporary humans she discovered that amazingly they would go hunting and would kill antelope pigs baboons other monkeys and eat them she discovered that they would share they valued meat they valued meat they valued meat to eat but they would also share it a little bit and by the time you’re racking up these male bondings the meat eating the meat sharing this is looking extraordinarily human like no other animal does these things and did they share for sexual favors the chimps did she discover that that the males would give meat to the females i can’t remember if i’m remembering that correctly well you may indeed remember what you read some colleagues and i have published a paper saying we don’t believe that for a minute that it does not look to us as though any of the evidence that has been brought forward in favor of the idea that chimpanzees that male chimpanzees will give meat to females in order to get them to mate none of that evidence is good right that’s pretty sophisticated behavior and it would imply some knowledge of trait like of trading with with future gain in mind it would seem to me i don’t think the problem of sophistication is difficult i think chimpanzees could easily handle that based on on other kinds of interactions they have the thing is that among chimps sexual system is very different from ours and females really really want to mate other males as much as possible i have seen female chimpanzee go into a a tree containing 10 males climb to the highest ranking male present to him hoping he will mate her and he turns his nose up at her and she then goes rank by rank down the ranks to the different males and finally will get some juvenile male to to mate with her that’s just symbolic of the fact that she is desperate to get mated as much as possible and and she she’s also with the chimps the the females are they have an estrous periods that’s not hidden correct it’s it’s very visually striking that’s right so the the alabia increase under the influence of estrogen so that you have quite a large swelling very pink very obvious from hundreds of yards away so males know when she has the swelling but there is a little bit of subtlety to this so in the first i mean she has the swelling for maybe 10 days at a time once a month during a period that she’s trying to get pregnant and during the first week of the swelling the males are not particularly interested in her they appear to know as it were that she is unlikely actually to have ovulated at that time they get much more interested towards the end of the period of swelling and that’s when the big males come in the high ranking males and and exert their their dominance to be able to compete for the female but she is interested in mating throughout this period and she can mate sometimes 50 times a day and the reason is very clear the reason is that any male who has not mated her is dangerous to her subsequent infant because a male who has failed to mate the logic is that he cannot be the father and if he’s not then the infant is worthy of being killed because how does he track that let’s not know it’s it’s almost certainly memory but we don’t know for sure you know and there are animals in which it happens with mechanisms other than memory so uh do you know the story about how it happens in mice no no well there’s a wonderful study of mice in which they they assess the infanticidal tendency of males by seeing how desperate they are to get at infants and what they were able to show is that the tendency to be infanticidal happens 21 days which is the length of gestation of a mouse um after a mating and the way they’re able to show that that it’s an account of the number of days is they manipulated the length of the day night cycle so that if you had day night cycles eight hours long and eight hours eight hours of day and eight hours of night then they would come in and try and commit infanticide after 21 of those if you extended them to 16 hours or longer of a day and 16 hours of night then they would commit infanticide they would try to commit infanticide 21 of those cycles later so some animals can have just an internal clockwork regardless of the actual time so if they hadn’t mated 21 days earlier they would assume that those infants aren’t theirs that’s right that’s right so you get the inhibition i hope i said that right i’ll decide after 21 dark light cycles i know it’s very remarkable such a uh sort of mechanical system uh applies to chimpanzees it’s much more likely that that they actually have a memory of of when and how often and under what circumstances they made it a particular female so we don’t know that um exactly but at any rate it um it certainly fits with all that we know from other primates that uh where there is some direct experimental evidence about this uh that females risk the lives of their infants if they do not mate with all of the males in the group on a regular basis and is that also is that characteristic of the bonobos as well uh the in the in bonobos the the females uh famously have even more sex than uh in chimpanzees and no infanticide has been recorded and so all one can say is that if there is an infanticide threat the females have overcome it by successfully persuading every male every time that he is a potential father right right so you can’t see any exceptions to that that’s right well so that’s a marked as you pointed out to begin with that’s a marked difference with human behavior all of that no including the in human females famously have concealed ovulation as well which is also a massive difference so human males cannot tell with any degree of certainty when a female is most likely to be impregnated um and it’s that’s an interesting evolutionary divergence and that’s something have you thought about is that something that you’ve that you’ve developed a particular theory about or thought about in it to any great degree is that something we could pursue because it’s a fascinating it is a fascinating difference yeah i mean um and i i would say that uh no i haven’t thought about it in detail and i would say nobody has a really convincing story but but the basic story is that um with humans we have shifted away from females mating all males in the group females mate with one male at a time essentially there’s a little bit of gene shopping but um but basically females are bonded to a particular male and and i do see the uh the bonding as quite strongly associated with cooking okay that’s not an obvious connection so i would love to hear about that well and what why do you why do you why do you believe that if you look now at people living in open-air societies then what you see is um a sexual division of labor in which females are cooking food for themselves and their children and for a male and uh they their big job in life is to produce food for the male from the point of view of their relationship with the male he absolutely needs to rely on having a meal when he comes back in the evening from whatever he’s been doing whether it’s been hunting or politicking with people in the neighboring group or or searching for enemies or or whatever and the reason he needs it is because he needs cooked food just like every other human and he doesn’t have time to cook the food himself so if his wife doesn’t cook the food for him then she’s in trouble um what uh the the sort of female is bonded to the male in the sense that the male needs her to provide food for him if if she is um sexually promiscuous then for obvious reasons the the male is upset and so he will punish her he will he will beat her uh you know he will maybe dispose of her um and get another female if he can and she needs him to do the things that he’s out doing having been fed like providing high quality protein for example and that’s the standard story is that that she needs him to produce meat and other good foods i think there’s something else though that is critical once you get to cooking and the reason that she needs him once you have cooking is that cooking exposes the cook to theft so when you cook you need a fire fire produces smoke everybody knows you’re cooking from a long way away people can detect the fact that you are cooking they can smell the smoke they can see the smoke just it’s just a very practical thing that means that for people who are lazy people who don’t want to cook their own food people who don’t even want to find their own food people who who maybe are sick a person who is cooking food is vulnerable to having their food stolen and a woman cooking the food is particularly vulnerable to men such as a man who has not yet got his own wife so bachelors are a problem for a woman and so might be the elder children of other females and so might be another another woman you have all sorts of sources of of risk and this is where a woman’s bond to a man is really important once cooking emerges because he can be relied on as somebody who can protect her not necessarily from actually being there at the time that a bachelor appears and tries to pinch some of the food on her fire but because she can go to the husband and say that lousy rat has taken some of my food and you know we’re getting ahead of ourselves in terms of thinking about the nature of human society because the thing i have to bring into this stage is that in all human societies you have a collection of men who form an alliance among themselves so that the husband of the cook is not just a man who can stand up for his wife and and and threaten any bachelor who approaches her with theft in mind he’s more than that because he can go to the rest of the men and say you know guys we’ve got a trouble we got some guy who is not respecting the norms in the society and that’s a much more potent threat than one guy standing up for a one-on-one fight because all of a sudden you’ve got the whole society now led by those men ready to enforce some quite severe punishment yeah you’re you you you’re starting to explore that idea and we’ll go back to that pretty deeply in your last book on on what you described as the self-domestication of human beings that that enforcement of moral norms and the control of of well hyper-aggressive behavior but also behavior that’s breaking rules yes so we’ll come to that but to come back to the question of what you asked about do male chimpanzees share food share meat with estrus females right females who are available to mate one of the reasons other than just the shortage of you know direct observations that you don’t expect this is because a male does not need to produce meat to persuade a female to mate with him in humans that is necessary or you know under the appropriate circumstances but not in chimps that’s not the way it works in fact more likely that a female would have to pay a male to mate her i mean not that really needs to happen but anyway this is an example to me of a behavior that was written up quite early in the study of chimpanzees in the 1970s on i think a too optimistic assumption that something that you saw that was reminiscent of human behavior might easily be interpreted as being equivalent so you know occasionally a male might allow a an it’s just female to to take some meat and everyone leaps on it and says hey look just like humans as it turns out females who are not estrus are more likely to get meat than a female who is estrus as it turns out when you have females with estrus with sexual swellings then there is less hunting going on than when those females are absent there’s all sorts of evidence now that you know this is not a confident relationship at all so i think it’s it’s an object lesson in the care you need for thinking about similarities between humans and primates and chimpanzees right well and one of the ways you you kind of check yourself against such things as a scientist is that before you generate any theory you know of spectacular you know of spectacular originality you might want to ensure that multiple lines of evidence suggest it and that those lines of evidence have been drawn from divergent and non-overlapping sources a trade off union yeah that’s right yeah exactly it checks you against your own projections yeah that’s right and that that kind of um caution applied particularly to one of the additional features that was emerging as i was joining the chimpanzee study in the 1970s which actually really happened while i was there and that is the discovery of something even more shocking than uh than hunting meat sharing and tool use the famous tool use you know all these things that were very similar between chimpanzees and humans well then it turned out that chimpanzees were holding territories against other chimpanzees and would sometimes go to the territorial boundaries look for opportunities to stalk and hunt and kill members of neighboring groups and those members of neighboring groups would be almost entirely adult males so now we had for the first time something that looked like a primitive kind of war yes and that the importance of that can hardly be overstated i mean when i first read that it just shocked me to the core because i thought well you know if you’re an optimist in some sense you might assume that the human proclivity for war is a consequence of let’s say maladaptive socialization or something like that that could hypothetically be easily controlled but to see an analog of that so striking in chimpanzees was well was an indication of just exactly how deep that proclivity is that that proclivity to dehumanize let’s say so to speak outgroup members and to treat them as prey yeah it’s an indication but but uh you know as my uh great advisor robert hind the uh superb animal behaviorist endlessly emphasized to me you know you’ve got to be really really cautious about thinking how to understand what this chimpanzee behavior means for for humans and i think you know we have been as a profession pretty cautious about it but um you know so one of the first things that happened was people said well it’s very likely that this pattern of chimpanzees killing members of neighboring groups males in neighboring groups is something to do with disturbance to that particular population and it won’t turn it’ll turn out not to happen in other populations and it took uh gosh um uh 30 years to develop enough confidence in what was happening in all of the other populations to be able to say you know what this is a characteristic feature of chimpanzees and by the time we had those data coming in we could also say what it was associated with and the answer is it was associated with high population density and large numbers of males in the aggressive community so you get lots of males together and they will look for opportunities to kill members of neighboring groups and what what is it not associated with uh it’s not associated with measures of human disturbance whether or not the forest had been subject to a bit of logging or how many people live nearby that sort of thing the chimpanzees you know don’t care about that sort of stuff they’re living their own lives and their social dynamics are concerned with what’s going on in their own species lives so why is a preponderance of males in the attacking is that just a matter of outnumbering the enemy or or are there other factors at play i’m numbering looks the important thing yes right because they won’t attack the chimps generally don’t attack outside their boundaries unless they they clearly outnumber those that they are targeting correct and that explanation for that they they they have a rudimentary sense of number of or amount something like that is it number or amount they have a rudimentary sense of that at least yeah i mean yeah they’re very smart and it turns out that the average ratio of the number of males in an attacking group to the number of males in the victim group is eight to one all right and what this comes down to is eight males attacking one you know it’s not 16 males attacking two and so in this average system when eight males attack one here’s what can happen uh you each of four males grab one limb and then you have a helpless victim and the remaining four can do what they like to that victim and they do and you know they can tear out his thorax and pull his testes off and twist the arms until the bones break and blood is coming out from everywhere and so on it’s a really nasty business and you know chimpanzees are it depends on exactly what measure you like on exactly what measure you like but here it’s maybe a three or four times stronger than humans they are immensely strong and so a chimpanzee fighting for its life could in theory impose immense damage on its attackers but the chimps that attack are so smart and and figure out exactly how to do this that there is not a single case out of some 50 attacks that have been reasonably well documented of any of the aggressors being damaged beyond a scratch so they know what they’re doing and and this is the you know the imbalance of power hypothesis that what has happened in chimpanzee social evolution is that because you have variation in the number of companions that individuals have within their communities as they walk about looking for opportunities to eat as well as possible and find females and all that sort of stuff you have variation which exposes occasional victims to occasional large groups and just the fact of having a lot of males in your group means that you have safety when attacking imbalance of power is enough to induce attack so you know for me this is um this is classic Lord Acton power corrupts and absolute power corrupts absolutely and so what’s in it for the attacking chimps what is it that they gain they don’t gain immediate food they don’t gain immediate females you know they don’t walk back to the communities um with a kidnapped female or anything like that they don’t show in the next few days increased acquisition of fruit from a tree on the boundary nothing like that but what they do gain is increased confidence in moving in an area that was previously more evenly used between the two communities so they decrease the probability that they’re going to be someone who’s one against eight it’s partly the safety problem like that but um um but also it gets it just gets them access to more resources in that area in general so you know during the months and years to come they’re able to spend more time in such and such a valley where they have killed and we now have nice data from from two different studies one in Tanzania and one in Uganda showing that you get occupation of the area where the killings have occurred and in one case beautiful showing all of the expected consequences for the quality of the diet so better food increased body mass even known of the the individuals that are able to occupy a larger area reduction in the time between births for those females so the females are feeling better the males are feeling better and even increased survival of the offspring in that community as a whole and how much killing does it take to produce such effects i mean is is it is the elimination of one or two individuals from a neighboring troop sufficient to do that like what scale does this have to occur at before those consequences emerged anyone know in those two best known cases in one case all the males in the neighboring community were killed i see so it was complete obliteration it was obliteration of the of competitors it was initially a small community there were only seven males in it and they they were all killed i shouldn’t say they were all killed i should say they all died and in four maybe five cases they were known to be attacked and killed so is that typical is the typical behavior to move in those situations towards complete elimination it’s typical and and it may well not be i mean you know if you’ve got a very large community neighboring then i could well imagine that they they kill several and it just means they they are able to dominate an area that was previously more evenly shared so in the case of the ugandan story at ngogo in kibale national park you had something over 20 kills that were made uh in various different parts of the boundary of the killer community but not enough was known about the neighbors to be sure what proportion that meant of that was of the neighbors it’s unlikely that any neighborhood communities were completely eliminated though those are those are immense communities that that killer community at that time uh had 25 fully adult and and over i think 35 adult and adolescent males you know this is an immense power and they were living in an area with just tremendous fruit productivity and and a number of communities that have a large number of males but but they were probably the the biggest boss on on the block so you you were working with good all when that initial rating behavior was documented yes i mean i saw some of the first raids um and uh it’s no wonder you wrote your first book then were inspired to do the work to write your first book which was demonic males i mean that must have really i mean that that’s quite a bombshell that that discovery like good always if if i remember correctly and informed him correctly good all was quite hesitant about sharing those results for some period of time i believe is that have i got that right or was she just being cautious or what what’s the story there no i don’t think that’s right oh okay um you know it’s funny william boyd wrote a book called browseville beach um which was obviously inspired by what happened in gomby and uh in that case the protagonist the sort of jane good old figure was very reluctant to share the results and i think that that may have affected the you know the popular understanding but no jane i mean 1979 um she published a a paper uh that was describing some of these results uh and um i think she’s always had a very faithful and honest approach to to presenting this she didn’t hide it yeah well i wasn’t i was certainly wasn’t suggesting that i mean i can imagine though that a scientist in her position would want uh what would you call to be damn sure of the proposition before releasing it on the world well fair enough yes and and uh i mean she’s um i think she’s been appropriately cautious you know she described what was seen um i think i probably did go a bit beyond her in um in in furring the more general tendencies um and so but but you know by 20 years later uh 96 when i published demonic males with dale pederson i think it was pretty clear what was going on and then as i said you know another 30 years later the data were really coming in very very solidly and i i mean in some ways i wasn’t too keen on the title of demonic males because it’s a little bit in your face but i wanted to make is that it is very extraordinary because uh we only know two species on earth or that stage we only knew two species on earth in which males live in groups often with their relatives and go out on raids to kill members of neighboring communities and and those were chimpanzees and humans yeah well when i picked up the book i mean i i was very interested in the scientific study of aggression at the time and when i picked up the book i thought the same thing about the title i thought but the book itself is a very uh scholarly examination of this proclivity and so so so for people who are listening who are interested it’s a very very solid book and it it isn’t uh it isn’t uh uh but it’s possible let’s say accessible yes well it’s accessible but it’s also it’s also careful it’s not sensationalistic at all yeah and and that’s the case with all of your work it’s very serious work and so so walk us through demonic males you’ve done some of that so we’re going to jump ahead a bit because you’ve done a lot of things and i want to cover a lot of it before we close you anything else you want to say about the first your your work with with with jane goodall and and and that that’s setting you up for for the long-term study of chimpanzees sure well i mean i i actually studied feeding behavior um when i was working with chimpanzees and i think it’s a great thing to study because it emphasizes you know the most important aspect of an ordinary animal’s life uh the just the daily search for food uh you know people uh when they come to film chimpanzees they often are expecting to see toulouse or dramatic sexual behavior or or something exotic in the first day or two and they say this is so boring you know they’re spending six hours a day just sitting in trees eating yeah well i think it was in your in the book uh catching fire maybe is it in that book do you document is it is it in that book that is it in that book that gorillas that the documentation of gorillas spending up to eight hours a day doing nothing but chewing leaves that’s right they have to do that because their diet is not particularly rich and so they don’t have time for much else and with chimps as well like it takes a lot of calories to keep a chimp going and so they’re there’s and that’s also perhaps offer some insight into why it took human culture so long to explode in the way it does it’s very difficult to get beyond hand to mouth living yeah i just think it’s a it’s a really helpful um sort of embedding of of the reality of animals lives and it’s not something necessarily comes across when you you read about their social behavior but they are spending most of their time um strategizing about how to get as much food as possible and and i found that immensely helpful but on the other hand it took me a long time before the penny dropped you know i actually tried to to uh to live like a chimpanzee a little bit in the sense of of eating what chimpanzees ate you know i i ate everything chimpanzees ate and i discovered very rapidly that i got extremely hungry if i did that the penny finally dropped in the 90s when i realized that there was a huge difference between chimpanzee and human diets and that is that humans cook our food and and that you know developed a whole new story so but i mentioned the importance of seeing chimpanzees feeding and spending time thinking about their attitude to to using their environment to maximize the amount of food they can get because it’s it’s a big problem for humans too and you know this is this is nature in the raw how on earth do you get enough to satisfy those endless pangs of hunger i think you’ve got to think of all these animals as being hungry all the time and it’s difficult for us to get into that mentality because we are never hungry we we can satisfy our food needs all the time right so so we underestimate how relevant that is by a massive degree i mean your book catching fire was struck striking to me i suppose in almost the same way that my encounter with the data showing that chimpanzees went on raids mean you you made the claim for example that well you think human beings have been using fire for about two million years which is yeah awful long time uh well in some sense it’s longer than i had longer than many suppositions and you also make a very strong case that our proclivity to use fire and cook has radically altered well our whole morphology our whole physiology our our our intestinal system our digestive system and that that’s provided us with the additional calories necessary to expend some resources on on brain power more resources on brain power have i got that right i hope i’m not doing your book injustice and the other absolutely no that that’s all right and the other big thing that it did is to uh hugely increase the amount of time we can spend on things other than chewing right right exactly to free it free us up to because to do nothing long enough to think about something other than immediate food food acquisition cooking softens food and and it softens it so much that that we can spend just a fraction of time chewing compared to any of our ape relatives you know so if we were eating our food raw we would be spending probably more than six hours a day chewing our food and as it is we spend less than an hour a day chewing our food so that saves us five hours a day and gosh you know that is important it’s uh it has different importance for females and for males in terms of how females males actually spend their time now and the irony is that females do a lot of food preparation i mean this is worldwide the only exceptions to it are in modern urban society but worldwide much of the saving of chewing time is translated into females for females into gathering food preparing it and cooking it for males there’s much more freedom given by that saving of time to go off and do high risk high gain activities like like hunting but also uh politicking visiting people in the neighboring camp chasing women in the neighboring camp and so on and the contribution to cultural production artistic production like aesthetic production bead making all of that that’s all exactly that’s right i mean you know all of a sudden you have a totally different attitude to time from from other right you have some of it exactly right right and so so two million years ago so what were our ancestors like two million years ago when they discovered fire and how it it you know i’m thinking how has that come about well one of the things that’s really interesting about fire as far as i’m concerned is that it’s it’s archetypally interesting you know if i spend time at my parents cottage and i used to bring my little kids up there and you know adults human adults will sit in a circle and look at two things they’ll look at infants and little kids like intently watch them non-stop as if they’re in eternally interesting they don’t habituate to that but we also don’t seem to habituate to fire and i’m wondering if you know two million years ago there was a mutation that that occurred that made someone some some ancestor absolutely unable to stay away from fire because it was no longer he was no longer able to habituate to it so it’s endlessly fascinating so i don’t know what you think about that idea but no there were probably various kinds of adaptation psychological um and physical and physical adaptations to to being near fire to being drawn to fire and so on but i think they would follow the discovery of um of being able to control it and just how useful it was and exactly how that happened i don’t know i mean you know my my personal fantasy goes along these lines that um you’ve got monstrolapithetine so that’s you know like a chimpanzee standing upright it’s uh just got a big jaw and eating raw foods big teeth it’s um about the size of a chimpanzee and it’s clear that there was increasing evidence in the fossil record of um i of meat eating and how that comes about uh who knows but uh but if they’re eating more meat then meat is not that easy to eat if it’s raw but it’s a lot easier to eat if you pound it if you if you just you know do a steak tartare on it and so my fantasy is that they were eating more meat they were using rocks to pound the meat sometimes sometimes they use wood but when they use rocks sparks would come out and sparks would sometimes start little fires and so they repeatedly be exposed to fires in a relationship to their activity and this would happen often enough that out of this would learn they’d learn the opportunity to um leave meat near a fire and taste the value you know how how often are animals edible animal animals trapped in grass fires in africa you know people often refer to that idea but i don’t think it happens very often at all i i’ve i’m not i don’t believe there’s any studies in which people have actually documented a number um most animals are able to escape by borrowing underground or running away from the fire um you know it’s conceivable that that that is the way it happened that it happened often enough that people you know figured it out that australopithetines figured out what was going on you know it’s it’s all speculation as to how fire was first controlled but um but i think what is uh clear is that once it was first controlled it would have had huge effects you know we know that all animals like their food cooked compared to like eating it raw or all that have been tested so you know not just our domestic animals but wild animals too all the apes for instance prefer it cooked they just haven’t figured out how to cook it and how do you account for that seems very strange that that that like how is it that that could possibly be the case like why do animals prefer cooked food it’s because what cooking does is essentially pre-digest food and and animals and and animals like their food as much digested as possible because the more digestion you can have done for you then the less you have to do it yourself and the there’s a major cost right well i can see i can see that it makes sense i just can’t see how they would have possibly developed the taste for it or the the odor preference or any of that i mean do you you don’t come to come i mean is it is it in some sense like partially decomposed food yeah maybe without a little bit um so you know softness i mean in general animals like their food soft because harder food is tougher and it’s you’ve got to do more chewing and so there’s a texture issue there’s a texture issue and probably the taste um you know um as you say a little bit of decomposition so if proteins have been partly denatured then you have more exposure to the amino acids that have a bit of sweetness to them uh have a bit of umami flavor and and all of those are indicators to even to an ape that the food is relatively going to be relatively easy to digest right bio available and ready for use right right right but actually no one has tested the spontaneous interest in the the odor of cooked food and that’s something would be really fun to do well it’s certainly a striking characteristic right well it’s certainly a striking characteristic of human response to especially caramelized meat which has a particularly distinctive and delicious odor yeah right right um so so the this is still an early an early science you know we don’t know that much about it but what we do know is that animals including the great apes prefer their food cooked even when they haven’t had any exposure to it you know when they’re naive and that once you are eating cooked food you are getting more calories you’re saving yourself the cost of digestion and you’re actually increasing the amount of the food that you are able to digest as well so the net result in experiments that uh that i and my colleagues have done uh you get indications of 30 50 increase in the number of calories i mean this is huge you know for five five percent more milk out of their cows you know they’re a millionaire and now we’re talking you know some tens of percent right right oh essential a doubling of available calories and and you also pointed out not only the the caloric improvement but the radical decrease in the amount of time it takes to do the processing like the chewing right so yes so so this would be really big and um and i think uh what it uh i mean the reason the argument that i make about why this happened surely at two million years ago is kind of twofold one is that everything fits at that point so that’s the point at which you see smaller mouth smaller teeth evidence of smaller guts to judge from the shape of the ribs and the pelvis and by the way um for the first time a commitment to sleeping on the ground because for the first time you have a construction of the of the organism you know the the human in a way that is not easy to climb trees ah so that made it possible for us to not have to climb trees that that’s the idea at least in part yeah the osteopath scenes could climb trees so they surely would have slept in trees but humans nowadays you know you can’t imagine them being able to regularly climb up into trees and always be able to make a nest in the way that a chimpanzee or an australian could so they’d have to sleep on the ground often well you have to be nuts to sleep on the ground if you don’t have fire to protect you so i think everything you know that all points to um to why it makes sense that fire was first controlled around two million years ago literally about 1.9 million years ago and then the other reason is that subsequently to that point no dramatic events happen in human evolution which could be consistent with the acquisition of something so important as the control of fire so you know there is no subsequent time that makes sense in terms of oh yeah they must have got fire and therefore therefore what nothing happens you know you get a steady increase in brain size you get a variation in tooth size but generally it’s declining but but no big things okay so so we’ve we’ve touched on autobiographical issues we talked about your work with good we we touched on demonic males and the rating and now we’ve we’ve touched on cooking and fire use so maybe because i want to get to your third book before we run out of time too you you got really really interested in aggression particularly aggression among males and it’s and it’s and the particular forms it takes in human beings and our close relatives but then in your last book the goodness paradox you really turned your attention to how that proclivity for extreme aggression came under some degree of social control yeah and that’s a fascinating issue in and of itself so maybe maybe we could talk about that you you distinguish first between two kinds of aggression proactive and reactive a classic distinction so do you want to start there and then elaborate out the thesis is that is that a reasonable way of approaching it it is so yes absolutely so the goodness paradox is the title of this book and it refers as a paradox to the fact that humans are so extreme with regard to aggression and non-aggression so we’re extremely aggressive in the sense that like chimpanzees we have these demonic tendencies to go off and kill members of neighboring groups using our overwhelming power when we can get a big group attacking a small group and so on in a way that uh that no other species uh no other mammals do and in a way that horrifies us in retrospect often and makes us drop drop our draw drop our jaws at our own behavioral possibilities yeah i mean you know the we’re still living in the shadow of world war two and the holocaust and and so you know for so many i mean almost everybody who writes about human behavior is affected by that and still thinking about how did that come to be and how do we avoid it in the future so you know there’s that that angle on humans and but the other angle which makes human behavior so paradoxical is that we are the kindest and most tolerant and most gentle of animals and people since the ancient greeks have said we’re like a domesticated animal you know we meet strangers we’re so nice to each other we don’t have automatic aggression we’re nothing like wild animals that we share food and make that the basis of many of our social interactions yeah and so you know for decades well for centuries people have tended to solve this paradox by saying either that we are naturally aggressive and we learn culturally to be nice to each other or vice versa and so you know the famous debate between hobs and russo as people put it now you know hobs takes the the naturally aggressive perspective and russo takes the naturally kind perspective and this goes on i mean there’s there’s a book recently published by a dutch historian called ronald breckman who’s called human kindness saying well actually humans are spontaneously naturally kind so you know it’s absurd in retrospect to think that people are trying to to arbitrate between these two views that one is correct or the other is correct because they’re both right you know i think it’s very very clear that humans have got tendencies for appalling violence which will be elicited under the appropriate circumstances regardless of what ethnicity or culture or religion you come from and equally it is very clear that people grow up to be spontaneously thoroughly moral and kind and tolerant with each other we have these two tendencies and you mentioned this division between two types of aggression a proactive and reactive it’s a division that that as you as a psychologist said it’s a familiar distinction that’s fine but i i will take credit for bringing it into biological anthropology because people thinking about the evolution of human behavior for some reason did not apply it well the short story is this the way to think about human aggression and non-aggression is that we are relatively elevated for the propensity for proactive aggression because all of the war and the holocaust stuff you’re talking about that’s all proactive right that’s planned that’s that’s multi-party that’s organized it’s social it’s it’s one group against another yeah and and it follows exactly the chimpanzee principle of imbalance of power you only do it if you can get away with it and feel very comfortable that you’re not going to get hurt in the process so you know the the killers of the jews and the gypsies and the homosexuals and the holocaust very very rarely got any pushback they were butchers and that’s the nature of proactive aggression so humans are elevated for that in the sense that we have a very high propensity to do it if we the circumstances are right which is right and part of that circumstance is that we’re defining the the entities upon which that aggression is afflicted as outside what constitutes human because within the human definition all the standard rules of morality apply and that’s sort of equivalent correct me if you think i’m making an error here that’s sort of equivalent to the chimp distinction between the chimps that are in their own group and the chimps that are from another group altogether you’re right and by the way in a shocking addition to that if you take the ethnographies of people living in small-scale societies including hunters and gatherers and small-scale farmers you find the same thing you find that within the ethno-linguistic society in other words the people who speak the same language we are humans and the other people are not humans right right and that’s very that’s a very common well and it’s i guess it’s also partly because you can rely on those who are like you it’s almost the definition of them being like you that they accept your definitions of right and wrong so that you can predict their behavior you can enter into a social contract with them with implicit understanding whereas with an outsider you don’t know what rules apply and so their behavior isn’t predictable and and they don’t obviously fall within the the the overarching definition of of moral and maybe that’s what you know underlies the definition of human in some sense for us yeah i mean that seems like a reasonable explanation but the net result is that even a total stranger in a completely weak state the the first thing that that you do you’re living in a small-scale society when you encounter such a person is not to say here have a cup of tea let’s find out your morals it’s a killing right right right so you know i say this because there’s a romantic view that among small-scale people particularly hunters and gatherers there is this extension of generosity of spirit to people of different languages and you can argue very strongly against that so let me ask you a question that just popped into my mind about that i mean it’s a compelling idea i know that in the in in in the i think it’s in genesis and the abrahamic stories there’s tremendous emphasis on the hospitality that has to be shown to a stranger and so that seems to be an ex that seems to be an exception to that general principle and so i think it’s a definition of the stranger that’s that’s the issue you know to me what you’re talking about would typically be a stranger who you do not know personally but who speaks the same language as you who’s part of you know the larger series of judaic tribes right right so still in still still in still encapsulated within the idea of what constitutes the central people yeah okay okay okay well that could well be i mean and obviously that’s going to be the case from a historical perspective because the idea of everyone who’s morphologically similar being human that idea obviously must have moved out from tribe to slightly larger group to larger group still and so forth as our groups got bigger and bigger and yeah well and maybe we’ve got some more we all all one world right right right well at least we can we do that to some degree romantic enemy is is horrendous right so you really have to think yourself back into a very different past to understand this so that’s all proactive aggression the proactive aggression the use of power to to damage anyone outside your group and then the reactive aggression that you describe is also characteristic of other of many many other animals who engage in male to male conflict so that’s not unique to human beings and and that’s that involves emotional reactivity it’s impulsive it’s immediate all this defensive that’s right it’s all those things so it’s what we ordinarily think of as aggression because so many people think of proactive aggression as something that is sort of just cultural and and just human taught and that sort of thing and even though there’s there’s very important cultural elements to it it’s part of our biology but reactive aggression is what people you know if you look up aggression in a textbook animal behavior it’s almost all about reactive aggression often exclusively about it so reactive aggression is testosterone fueled it’s it’s losing your temper as you say it’s impulsive it’s motivated by anger not not only by anger but anger is a anger frustration shame associated with emotions that’s right and and what’s what’s striking about humans is that we are very down regulated for reactive aggression compared to our close relatives so and the way that you can see this manifest is that the rate at which you get actual physical aggression happening in a small scale society in humans compared to in a group of wild chimpanzees is two to three orders of magnitude difference that is to say hundreds to thousands of times less frequent in humans than in chimpanzees or in bonobos too you know the famously peaceful bonobos but nevertheless bonobos are not nearly as peaceful as humans so we have when you’re way down the scale of reactive aggression and at the same time we’re way up the scale on proactive aggression and the goodness paradox is a story of how do we get this astonishing mixture and I think you know we actually have a really good story for it now a really good understanding and and it yeah well some of it in the book some of it you outline intense attempts by people within human social groups everywhere to socialize children into controlling their reactive aggression yeah and I know there’s literature I interviewed Richard Trombley on this YouTube channel I saw the podcast yeah oh okay so you know we talked about the study showing that you know a small percentage of two-year-olds are spontaneously aggressive if you put them in groups of other two-year-olds it’s only about five percent and virtually all of them are male and virtually all of them are socialized out of that by the time they’re four but a small proportion aren’t and they tend to be lifetime aggressors and those are the ones that well you have a story about them I think well I mean I think that’s the the residue of a population that would have been 100% like that if you go back 300,000 years ago you know all our babies would have been highly aggressive and would have retained that aggressiveness throughout life and the reason we can say that is you know to two main points first of all our anatomy compared to our earlier ancestors looks like the anatomy of a domesticated animal compared to a wild animal and when I’m saying our earlier ancestors I’m thinking very specifically of what happened around 300,000 years ago so this is when we first get the first glimmerings of our species moving into sapien ization sapien ization process of becoming homo sapiens people now say it started about 300,000 years ago that thanks to fossil discoveries in morocco and that’s when you first start getting smaller teeth and smaller mouths indicative of a trend that will get increasingly strong by the time you have homo sapiens as a recognizable species you have several of the characteristics that archaeologists use to mark a domesticated animal compared to its wild ancestors the four characteristics they use are smaller teeth and jaws reduced differences between males and females reduced sexual dimorphism a reduction in body size and those three things all happen fairly early in homo sapiens and then the fourth thing is a reduced brain size and astonishingly there is evidence for reduced brain size in homo sapiens compared to our earlier phases right but no nests not necessarily any loss of cognitive power just like in domesticated animals there’s no evidence of a loss of cognitive power in domesticated animals compared to their wild ancestors even though they have smaller brains and you i think you posited that that was a consequence of decreased size of the brain areas associated with reactive emotions that’s part of it anyways um yes you you may be extending slightly beyond what i said but i actually do think that that’s right uh it seems to me that there’s quite a bit of evidence that um part of the contribution to brain size is associated with reactive aggression and so you know bonobos are less reactively aggressive than chimpanzees they have smaller brains than chimpanzees females are less reactively aggressive than males females a whole bunch of species have smaller brains domesticated animals all have smaller brains than their wild ancestors and and there’s even you know some very provocative evidence that um um if you give testosterone to uh humans then um it increases the size of the brain even to adult humans so now you mentioned in in the goodness paradox some early hypotheses about how human beings might have become domesticated because obviously we domesticated domesticated animals and there were wild hypotheses like uh some sort of super race that had domesticated this all and then disappeared and these were very early speculations but you have a hypothesis about how this might have come about uh that doesn’t involve such uh what would you call extreme speculation yeah and it comes originally from christopher bohem uh who was an anthropologist who went to look at chimpanzees and he was really struck by the huge difference between humans and chimpanzees in the existence of an alpha male bully in chimpanzees you have an alpha male bully who gets what he wants by using his personal physical power in humans you don’t have that and we often talk informally about humans having alpha males but it’s not an alpha male in the primate sense because the human supposed alpha does not get that status or or achieve what he wants by using his personal physical power it’s all through coalitions but in chimps and bonobos and baboons and every other primate it’s not by coalitions it’s by his personal physical ability to defeat everybody else now you sometimes get in humans in small scale societies you sometimes get a man who tries to do that who tries to you know kick sand in the face of every other male and take their wives and take their resources make them feel small and thoroughly mean to them just by being the bully on the block and when that happens there is a consistent solution because you have to think about societies in which there’s no police there’s no nowhere to help you you’re just on your own in your society and here is this guy who is being incredibly objectionable and may actually kill other people but even if he doesn’t kill them he’s trying to he’s taking their wives he’s pushing them around so there’s various kinds of social responses people can try pleading with him to behave better they can laugh in his face they can ostracize him they can ignore him they can try and move away and exile him just by going away but none of those mechanisms will work in the face of a really determined desperate so in the end he gets killed now that’s what happens nowadays and what christian weapons weapons would have contributed to that too i suspect because it’s it’s easier to be a bully when you’re huge and everyone else is small and they don’t have weapons but once weapons emerge the advantage of physical strength is decreased substantially at least in principle sat well yeah i mean weapons play a funny role and it’s almost certain that the kinds of weapons that would be needed for a bully to use them existed long before 300 000 years ago you know they’re very nicely preserved spears from 400 000 right yeah i’m thinking more about weapons used against the bully well yes but uh you know animals without weapons can kill others quite safely even nowadays you have descriptions of humans killing without weapons so how much weapons you really mattered is unclear you can kind of argue it both ways but but either way um the uh what what you see in the present is the argument that is taken back into the past and i like this argument a lot because i think it is a really tidy explanation for the fact that beginning around 300 000 years ago we had this reduction in reactive aggression and there is no other explanation other than a communal effort at executing that can account for the removal of this would-be desperate this bully who uses his physical strength that’s why no other primate has escaped having an alpha male bully only humans have converted an alpha male bully into an alliance of males among whom there is a sort of formal level of equality and if anybody in that alliance tries to throw their weight around they know what will happen they will get taken out as as the bully originally did right so you you paused in in the goodness paradox that there’s been enough of that in human societies over the last very long period of time we have markedly decreased the propensity for reactive aggression to such a degree that it’s also transformed our morphology and our psychology absolutely at the biological level right right and you know it probably accelerated over time uh the the loss of reactive aggression uh the move towards this domestication like species that we are now um people sometimes want to suggest that other forces like female choice would have come in females choosing to mate with the kinder gentler more domesticated male the problem with that is that as long as you had a bully who was capable of exerting his physical force it wouldn’t matter if a female was exerting female choice you know she would come along and say i don’t want to mate with you and he would say too bad and punch her chosen male in the face and take her off and and mate with her and rape her and you know it’s a brutal vision but this seems to me to conform to what we know about primates and to be the only explanation for how humans escaped what other primates have in terms of alpha males and there is an obvious reason for what it was that enabled humans to make that escape and that is language because what language enabled the the beta males the coalition of the subordinated males to do is to make a plan and now all of a sudden they could convert their individual tendencies for proactive aggression which are not enough into an alliance and of course it’s very difficult you know it’s not just simple language because they’ve got to be able to work out how to approach someone and suggest this idea you know to float the possibility of killing the offender without themselves being exposed to the possibility of being shopped to the offender and themselves being killed so it’s a complicated business and i say that to emphasize that other species of humans like neanderthals probably had pretty good language themselves but i think the ancestors of sapiens must have been the ones whose linguistic ability for whatever reason got to the point of being so sophisticated that they could dare develop the sort of plan that would enable them consistently to get rid of the supreme bullies there there was a movie i unfortunately don’t remember its name but it was released in the 1980s and maybe one of the viewers of this can supply us with the name it it documented the lives of a very of villagers a very isolated and archaic japanese village and there was a group of villagers a family of villagers in there that consistently broke the rules and pilfered food and all of the villagers conspired together as a consequence of that and in the night crept into their house and killed all of them it’s exactly the scenario you describe it’s an unbelievably striking movie i saw it in a repertory theater i’d really like to know i’d really like to know the name of it at the end of it two men carry their aged parents off to a mountain to abandon them which is the typical way of dealing with elders in this particular village and one woman goes voluntarily in the other fights and struggles and it’s a horrific scene so that’s another part of the movie but i would like to find it given this conversation because it’s exact representation of the process that you described it’s the only thing i’ve ever seen like that yeah i mean i haven’t heard of that movie but but i can cite you a number of you know cases nowadays even in texas where similar sorts of things happen where you get isolated communities where the police are inadequate and and people just take it on themselves but the case you mentioned is not quite like the one i was mentioning because it involves people being punished for pilfering food but it it yeah it’s not that’s right it’s it’s more it’s breaking it’s breaking the moral code it should be a variant of that yes and i think you know it’s very significant what you just said because i think that once you have the ability to safely execute using the absolute power of an alliance against a victim you also have the ability to control society through social norms so do you do you think is what you’re claiming the transformation of proactive aggression into use within the group to control reactive aggression within the group so is what is what happens that the conspiratorial parties define the bully as a consequence of his behavior as non-human and are then able to use their intrinsic proclivity for proactive aggression to target him yeah yeah i mean whether they define it as non-human that’s uh you know yeah i’m just wondering if he fits it if he starts to slip into that category because that category obviously exists in some sense because it enables these acts of proactive aggression to take place right there has to be some psychological mechanism that is sufficiently profound to allow the perception of a morphologically human being as not human so that you can attack them without you know without violating your moral code well i have some accounts which are that they say it’s time to send but uh whoever back to the witches because he looks like a witch right right right right right and you talk about witches and sorcery to some degree in your book too and and and and that’s also a topic of gossip right so there will be psychological mechanisms that allow people to justify to themselves but what they’re basically doing is making themselves safe from you know someone who is a tyrant and but but my you know i really want to come back to this point that i think there are two processes that go on once humans have this ability to kill in this predictable safe way and the first is the loss of the alpha male and therefore the loss of alpha male genes and therefore the loss of reactive aggression and therefore the self-domestication that actually ends up defining our species in terms of our morphology as well as our behavior we are the domesticated version of the species that lived 300 000 years ago but the other process that happens is that because this group of males who have now acquired the power of life and death over an alpha male they have acquired the power of life and death over everybody in the group so they are the supreme dictators as a group of what is okay they now therefore have created a world in which they can specify what is good and what is bad what is right and what is wrong they have created a moral system and from then on i think you see an intensification of the degree to which males are ruling the society very often the rules that they impose will be good for everybody such as there shall be no murder except when we say it’s a good thing um but sometimes the rules will not be good for everyone in society such as when we tell females that we want them to have sex with a stranger then they’re darn well going to do it or the bachelors will not be allowed anywhere near the women or our choice pieces of food in other words there are selfish aspects to the male what has become now something like a patriarchy which go alongside the aspects that are good for the group as a whole and and i think that this is a concept that is useful for thinking about the origins of of many of the major political institutions or the major social institutions and the obvious ones are the system of justice the system of religion the systems of politics the systems of law ultimately going back to alliances among males who have agreed among themselves not to have any kind of alpha male and who then have the power that they can impose throughout society that is a really good place to bring this discussion to a close we covered a tremendous amount of material today in the last 90 minutes or so and touched on the three your three books i’m going to repeat their titles for everyone so that people who are interested can read them which i would highly recommend maybe i’ll let you do that because i’ve lost my notes here i want to get the titles right so the first one was demonic males demonic males apes and the origins of human violence 1996 yeah and then catching fire catching fire how cooking made us human 2009 and then the goodness paradox that’s a relationship strange relationship between vials and virtue in human evolution published in 2019 well thank you very much for talking to me today and for walking walking all me through that and and and the audience that i’m have no doubt will appreciate this through it as well and there’s lots of other things i would have liked to have talked to you about and that really flew by as far as i was concerned so i hope everyone else feels that way as well and maybe we can get a chance to talk through some of these things i’d be interested in hearing more from you about your ideas about how more complex political structures might have emerged from this initial uh say consensus against violence something like that yeah that’s that’s a very interesting development developmental historical idea i suppose so anything else you’d like to add to to close things off or do you want me to have another hour and a half yeah well that would be nice and we’ll do it again i’d like to do that again maybe we can talk together with france de wall if i can convince him to do that that might be fun that would be interesting yeah right all right well thank you very much thank you so much my pleasure it was it was and and thanks again for agreeing to do this it was a pleasure talking to pleasure meeting you and thank you for for your books i’ve learned a tremendous amount reading them and enjoyed it very much too so till we meet again okay all right all right bye bye you