249. Primatologist Explains the 1% Difference Between Humans & Apes | Richard Wrangham

[0] Welcome to episode 249 of the JbP podcast.

[1] I'm Michaela Peterson.

[2] In this episode, Dad spoke to Richard Rangham about his time researching chimps with Jane Goodall, what chimps can teach us about ourselves, and the role things like cooking played in the cognitive development of humans, hint or meat eaters.

[3] Richard is a biological anthropologist at Harvard, specializing in the study of primates and the evolution of violence, sex, cooking, and culture.

[4] He's also a McArthur Fellow, the so -called Genius Grant, and the author of books like The Goodness Paradox and Demonic Males, Apes and the Origins of Human Violence.

[5] More specifically, they discussed the impact fire had on human development, proactive versus reactive aggression, sleep darting elephants, commonalities between chimps and ourselves, and different aspects of chimp behavior like hunting, infanticide, friendship, and their mental checklist before attacking other chimps.

[6] We hope you enjoy this episode.

[7] Hello, everyone.

[8] I'm very pleased to have today as a guest on my YouTube channel and podcast, Dr. Richard Rangham of Harvard University.

[9] 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.

[10] I ran across Dr. Rangham's work back in 1996.

[11] 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.

[12] And I learned an awful lot from that book.

[13] And since then, he's published two others, Catching Fire, how cooking made as human, also not a title that you would expect, because it's not as if people popularly think about cooking as something that made as human.

[14] So that was very interesting.

[15] It's a great book.

[16] And then more recently, the goodness paradox, the strange relationship between virtue and violence and human evolution, which was published in 2019, Dr. Rangham began his career.

[17] with Jane Goodall, studying chimpanzees in Gombay Stream National Park in Tanzania, Tanzania, and began an association there with Diane Fosse, another stellar primatologist who worked primarily with gorillas.

[18] He was then a professor at the University of Michigan, and finally, Ruth Moore Professor of Biological Anthropology at Harvard, where he is now.

[19] He's also a MacArthur fellow, a MacArthur fellow, which makes him a recipient of the prestigious prize.

[20] popularly known as the genius grant.

[21] And so we're going to talk today about human evolution, primate evolution, aggression, the use of fire, and all those things.

[22] And so welcome, Dr. Rangham.

[23] Thank you very much for agreeing to talk with me today.

[24] Great to be here.

[25] Great to meet you.

[26] Thank you.

[27] Thank you.

[28] So I didn't know, or perhaps I had 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.

[29] So do you want to walk us through your, how did your career develop?

[30] How did you develop an interest in primatology and anthropology?

[31] And maybe you could also define those fields for everyone.

[32] I love being in the wild.

[33] I love being in nature.

[34] As a kid, I liked birdwatching.

[35] And that took me to more and more remote places.

[36] By the time I was 17, I spent nine months in Zambia in a national, Park in which it was called Kafui National Park.

[37] It had something like 20 people living in it, and together with its border areas, it was slightly larger than Switzerland.

[38] So it was a wonderful opportunity to really get a sense of what it's like to live in the wild.

[39] And I went to Oxford University to read Zoology as an undergraduate.

[40] And after that, I wrote to Jane Goodall and said, is there any chance of being able to work with her?

[41] 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 behavior to their own problems of life in the wild.

[42] So I've got two questions that stem from that.

[43] So what in the world were you doing living in that park when you were 17 and how did you manage that?

[44] And how did that come about?

[45] 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 behavior?

[46] Two very different questions.

[47] So I told you, I just love the wild.

[48] And I'd been on sort of expeditions to more remote parts of Britain in my adolescence.

[49] But I saw the opportunity to do more.

[50] 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?

[51] and a guy called John Hanks, who ended up as 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.

[52] I was paid a shilling a day and just had the most incredible time.

[53] So what were your living conditions like in that particular time?

[54] Well, they were very civilized.

[55] I mean, you know, I had a regular little cabin.

[56] in a small sort of camp that was ultimately destined to become a tourist venue.

[57] It wasn't really at that stage.

[58] It was a remote area.

[59] You had to drive a couple hundred miles to get there.

[60] But of course, we did go camping.

[61] And so that was a major thrill, you know, going camping in an area that was full of really wild animals and no opportunity to call for help, as it were.

[62] You're really living on your own.

[63] So if you ran into wild animals, you had to know what to do.

[64] In my first few weeks there, I went for a walk in an inadvisable area and found myself catching up on a rhino and was only stopped from bumping in.

[65] into it in thick vegetation by the arrival of, well, I was lost and people were shooting rifles to tell me where to go.

[66] So there's just a little adventure for a 17 -year -old learning about self -sufficiency in the wild.

[67] And you mentioned, were you studying elephants at that point?

[68] I was participating.

[69] I wasn't studying anything myself, but I was a system.

[70] And yes, so I mean, this was very dramatic stuff because we were trying out a new drug, which has since become a standard drug for immobilizing animals, mammals in the wild, immobilon, it is now called.

[71] But at that time, the delivery systems were poor and the doses were unknown.

[72] So we would walk up to.

[73] 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 market 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 you know it's like a table got four strong legs.

[74] And so then the question is, is it asleep?

[75] Seems like an important question.

[76] Well, exactly.

[77] 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.

[78] 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 if we were pushing on the left and then it would sway back towards us.

[79] So we had to run backwards and then catch it again as it swayed further forwards and so on.

[80] I mean, you can see what sort of thrill all this was for a young aspiring naturalist.

[81] It sounds like a study that would be very difficult to get through a research ethics committee.

[82] Yes, and rightly, actually, because in the previous year, the person in my position had been killed by elephants.

[83] So there were serious aspects to this.

[84] And we did have to take what precautions we could, certainly.

[85] Right.

[86] Yeah, well, I wasn't necessarily saying that favorably, I mean, to gain knowledge requires a certain degree of risk.

[87] And I suspect that's particularly true.

[88] When you're out in the wild, observing wild animals, that's not something you can make 100 % safe.

[89] I mean, obviously you don't want to be foolhardy.

[90] But, and there is the thrill of the adventure that goes along with that, that's a necessary part of it, I think.

[91] Although, by the way, when a woman called Nancy Howell had her son killed in, while she was doing field work in South Africa, or I think it might be in Botswana, she did an analysis of deaths among anthropologists doing field work and found that the major source.

[92] of death was car accidents.

[93] Right, right.

[94] You know, the roads are bad.

[95] Right.

[96] Yes, well, in car accidents are a major killer everywhere.

[97] So maybe that's a good rule of thumb for danger.

[98] If it's safer, if it's no more dangerous than driving a car, which is something almost everyone accepts.

[99] Maybe that's safe enough.

[100] So, okay, so you got accustomed to this and you found that you liked it.

[101] You went back to Oxford and studied zoology.

[102] and then you wrote to Jane Goodall.

[103] I've got that timeline, correct?

[104] This was the late 1960s that I was studying zoology.

[105] And there were two writers whose work had sort of really impinged on the public imagination at that time in relationship to human evolution.

[106] There was Robert Ardry, 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.

[107] And there was Desmond Morris, who wrote a book called Naked Ape, in which he emphasized in particular the sexual side of human evolution.

[108] 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.

[109] Simultaneously, this was a time when the discovery of the social structure of all sorts of large mammals was taking giant, leaps forward.

[110] 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 Waterbuck.

[111] It's a very widespread antelope.

[112] Behavioral ecology means understanding the social behavior in relationship to all the environmental pressures.

[113] This was the first such study done on Waterbuck.

[114] no particular surprise because many of the first studies were being done at that time on any animal animals on on lions and gorillas and and many different things so there was a sense of of impending discovery and what happened even in the late sixes 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.

[115] Some species would have females that readily mated every different male in the group.

[116] Others would have a society in which females would only mate with one male.

[117] All sorts of fascinating differences were emerging and hints were coming through about how you could explain these.

[118] So this was a very exciting moment because When you combine it with the opportunity to think about humans, then we could get, you know, a long way beyond the kind of very naive political science interpretations of human behavior.

[119] We could really embed it in the environment in which humans had evolved.

[120] So that's a tricky issue, you know, because one of the things your work highlights, and this has been the case with other primatial.

[121] particularly more recently is that, because you just mentioned that species that are even very closely related can have radical differences in their fundamental behaviors.

[122] And you highlight the differences, for example, between bonobos and chimpanzees, which are very closely related.

[123] And so then you ask yourself, well, if bonobos and chimpanzees can be so biologically similar, structurally similar, let's say, but so behaviorally different, how is it that you decide, what's reasonably generalized to the human case.

[124] And why should you believe that anything could be given, right?

[125] Because there's similarities and differences between all of the apes.

[126] And so how do you prioritize the similarities versus the differences?

[127] And how do you decide when you can draw conclusions that are more universal rather than local to that particular species?

[128] 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 or the great apes you know so we have 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 suddenly chimpanzees but they were just one species of great ape among the other main three, gorillas, bonobos and orangutans, that all seemed roughly equally important for understanding human evolution.

[129] There was the apes and there was humans.

[130] An enormous shock happened in 1984.

[131] 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 and kneeling system and they applied it to apes and humans and they claimed that chimpanzees and bonobos were the most closely related species.

[132] And then chimpanzees, bonobos, and humans were more closely related to each other than any of them were to gorillas.

[133] So that kind of put us in the chimp category.

[134] Now, let me ask you, just there, I want to ask you a question about that DNA technique.

[135] Now, if I remember correctly, the way that was done to begin with was to take DNA from separate species and to heat it so that it split apart.

[136] And then to have the DNA from the different species joined together and then to assess how tightly bonded the DNA was to the between species.

[137] And the hypothesis was the more tightly bonded it was.

[138] So the harder it was to pull apart once it regrouped, the more closely related the species was.

[139] That was the first way of doing DNA simileged.

[140] similarity analysis.

[141] That's been superseded, but was that the 1984 work?

[142] Very good.

[143] Yes, absolutely.

[144] And the technique was a little crude, unzip things and zip them together and see how tough the other pull apart.

[145] And that crudeness meant that people could challenge the results.

[146] And it took maybe a decade for people to become, you know, the profession as a whole, to become really convinced at 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 the chimpanzees and humans are more closely related to each other than either is to a gorilla.

[147] What that means is that the common ancestor of chimps and humans is very likely in the mold of the chimpanzee gorilla.

[148] 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.

[149] Either that, or there's been a fantastic degree of evolutionary convergence between some mysterious ancestor, which would become more guerrilla -like and become more chimp -like.

[150] But no one thinks that that is the case.

[151] Right, so the idea is that, and this is what, how long ago did guerrillas split from chimps, hypothetically is that like 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 bonnobos 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 of getting an increasingly confident assessment of that.

[152] But anyway, much more recently, long after we had left the chimpanzee bonobo line.

[153] Right.

[154] 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 australopithicines and they gave rise to our genus homo about two million years ago and ever since then our ancestors have basically looked like us 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 need the big size heavenly muscled but nevertheless we can we can ask We can estimate 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.

[155] Is that, is that, and then there's obviously fossil dating, but what other techniques are used to estimate the divergence dates?

[156] Yeah, the more recent times, I would say we've got the fossils.

[157] So, you know, we have a very good fossil record back to more than two million years ago.

[158] And we can be very confident that our ancestors were indeed homorectus, which, as I say, was the first thing that was fully bipedal.

[159] 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 it's getting increasingly broken but nevertheless there's half a dozen different species and more that have been recognized in the african habitats and 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 lived in a forest.

[160] Forests don't preserve bones well.

[161] They tend to be too acid and the bones just decay very quickly.

[162] But I bet eventually someone will find a pretty good, you know, something close to the chimpanzee human common ancestor.

[163] So 10 million years.

[164] Okay, so let's go back to the biography.

[165] Now 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.

[166] And by that time, you had an undergraduate degree?

[167] I did.

[168] That's right.

[169] So you started working with her in Tanzania?

[170] Tanzania?

[171] Tanzania.

[172] In 1970.

[173] Yes.

[174] In 1970.

[175] So what was that like?

[176] And what was it like to work for her?

[177] And what were you doing during that period of time?

[178] For my first year, I was a research assistant to her.

[179] I was just learning the job.

[180] 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.

[181] You know, this is not just an antelope.

[182] And it's difficult to say exactly what's going on, you know, but there's something about the use of eyes and something about 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 quite sophisticated.

[183] And of course that makes it incredibly interesting.

[184] Now this was 1970s.

[185] It's long before I had any kind of concept that we were looking at a good model of the human ancestor.

[186] So this was just, you know, another ape.

[187] But here's what was so amazing.

[188] You know, I happened to arrive there at a time when some very fundamental discoveries were being made.

[189] 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.

[190] She discovered that amazingly, they would go hunting and would kill antelope, pigs, baboons, other monkeys, and eat them.

[191] She discovered that they would share them.

[192] They valued meat.

[193] They valued meat.

[194] They valued meat to eat.

[195] But they would also share it a little bit.

[196] And by the time you're racking up these male bondings, the meat eating, the meat sharing, this is looking extraordinarily human -like.

[197] No other animal does these things.

[198] And did they share for sexual favors, the chimps?

[199] Did she discover that, that the males would give meat to the females?

[200] I can't remember if I'm remembering that correctly.

[201] Well, you may indeed remember what you read.

[202] Some colleagues and I have published a paper saying, we don't believe that for a minute.

[203] That it does not look to us as though any of the evidence that has been brought forward in favor of the idea that male chimpanzees will give meat to food, females in order to get them to mate.

[204] None of that evidence is good.

[205] Right.

[206] That's pretty sophisticated behavior and it would imply some knowledge of trading with future gain in mind would seem to me. I don't think the problem of sophistication is difficult.

[207] I think chimpanzees could easily handle that based on other kinds of interactions they have.

[208] The thing is that among chimps, sexual system is very different for hours and females really really want to mate other males as much as possible I have seen female chimpanzee go into 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 and she then goes rank by rank down the ranks to the different males, and finally we'll get some juvenile male to mate with her.

[209] That's just symbolic of the fact that she is desperate to get maided as much as possible.

[210] And she's also, with the chimps, the females are, they have an estrus period that's not hidden, correct?

[211] It's very visually striking, that's right.

[212] So their labia increase under the influence of estrogen so that you have quite a large swelling, very pink, very obvious, from hundreds of yards away.

[213] So males know when she has the swelling, but there is a little bit of subtlety to this.

[214] 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.

[215] And during the first week of the swelling, the males are not particularly interested in her.

[216] They appear to know, as it were, that she is unlikely actually to have ovulated at that time.

[217] They get much more interested towards the end of the period of swelling.

[218] And that's when the big males come in, the high ranking males, and exert their dominance to be able to compete for the female.

[219] 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 it's almost certainly memory um 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 there's a wonderful study of mice in which uh they they assess the infanticidal tendency of males by seeing how desperate they are to get at infants.

[220] 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, after a mating.

[221] And the way they're able to show that it's an account of the number of days is they manipulated the length of the day, night cycle.

[222] 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.

[223] If you extended them to 16 hours or longer of day and 16 hours of night, then they would commit infanticide, they would try to commit infanticide 21 of those cycles.

[224] later.

[225] So some animals can have just an internal clockwork, regardless of the actual time.

[226] So if they hadn't mated 21 days earlier, they would assume that those infants aren't theirs.

[227] That's right.

[228] That's right.

[229] So you get the inhibition.

[230] I hope I said that right.

[231] It's the inhibition after 21 dark light cycles.

[232] That's remarkable.

[233] Such a sort of mechanical system applies to chimpanzees.

[234] It's much more likely that they actually have a memory of when and how often and under what circumstances they made it a particular female.

[235] So we don't know that exactly.

[236] But at any rate, it certainly fits with all that we know from other primates that where there is some direct experiment.

[237] evidence about this, 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.

[238] And is that also, is that characteristic of the Bonobos as well?

[239] In Bonobos, the females famously have even more sex than in chimpanzees.

[240] And no infanticide has been recorded.

[241] 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.

[242] Right.

[243] So you can't see any exceptions to that.

[244] Well, so that's a marked, as you pointed out to begin with, that's a marked difference with human behavior, all of that.

[245] Nothing like that at all.

[246] No, including the human females famously have consistent.

[247] sealed ovulation as well, which is also a massive difference.

[248] So human males cannot tell with any degree of certainty when a female is most likely to be impregnated.

[249] And that's an interesting evolutionary divergence.

[250] And that's something, have you thought about, is that something that you've developed a particular theory about or thought about in it to any great degree?

[251] Is that something we could pursue?

[252] Because it's a fascinating, it is a fascinating difference.

[253] Yeah, I mean, I would say that, no, I haven't thought about it in detail, and I would say nobody has a really convincing story, but the basic story is that with humans, we have shifted away from females mating all males in the group, females mate with one male at a time, essentially.

[254] There's a little bit of gene shopping, but basically females are bonded to a particular male.

[255] And I do say, see the bonding as quite strongly associated with cooking.

[256] Okay, that's not an obvious connection.

[257] So I would love to hear about that.

[258] Well, why do you believe that?

[259] If you look now at people living in open -air societies, then what you see is a sexual division of labor in which females are cooking, food for themselves and their children and for a male and 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 politics with people in the neighboring group or or searching for enemies 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 what the so the female is bonded to the male in the sense that the male needs her to provide food for him if she is sexually promiscuous then for obvious reasons the male is upset and so he will punish her he will beat her he will maybe dispose of her and get another female if he can and she needs him to do the things that he's doing having been fed like providing high quality protein for example and that's the standard story is that she needs him to produce meat and another 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.

[260] Fire produces smoke, everybody knows you're cooking.

[261] From a long way away, people can detect the fact that you are cooking.

[262] They can smell the smoke, they can see the smoke.

[263] It's just a very practical thing.

[264] 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 maybe are sick, a person who is cooking food is vulnerable to having their food stolen.

[265] And a woman cooking the food is particularly vulnerable to men, such as a man who has not got his own wife.

[266] So bachelors are a problem for a woman, and so might be the elder children of other females, so might be another woman.

[267] You have all sorts of sources of risk.

[268] 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 threaten any bachelor who approaches her with theft in mind.

[269] 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 this 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 starting to explore that idea, and we'll go back to that pretty deeply in your last book on what you described as the self -domestication of human beings, that enforcement of moral norms and the control of, well, hyper -aggressive behavior, but also behavior that's breaking rules.

[270] Yes, so we'll come to that.

[271] But to come back to the question of what you asked about, do male chimpanzees share food?

[272] chair meat with estra's females who are available to mate one of the reasons other than just the shortage of 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 not the way it works 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 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 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 is just are more likely to get meat than a female who is mistress 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.

[273] So I think it's an object lesson in the care you need for thinking about similarities between humans and primates and chimpanzees.

[274] Right.

[275] Well, and one of the ways you kind of check yourself against such things as a scientist is that before you generate any theory, 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.

[276] A true Darwinian.

[277] Yeah, that's right.

[278] It checks you against your own projections.

[279] Yeah, that's right.

[280] And that kind of caution applied particularly to one of the additional features that was emerging as I was joining the chimpanzee study.

[281] in the 1970s which actually really happened while I was there and that is the discovery of something even more shocking 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.

[282] And those members of neighboring groups would be almost entirely adult males.

[283] So now we had for the first time something that looked like a primitive kind of war.

[284] Yes, and the importance of that can hardly be overstated.

[285] 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, meladaptive socialization or something like that that could hypothetically be easily controlled.

[286] 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 proclivity to dehumanize, let's say, so to speak, outgroup members and to treat them as prey.

[287] Yeah, I mean, it's an indication, but, you know, as my great advisor, Robert Hein, the superb annual 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 humans.

[288] And I think, you know, we have been, as a. a profession pretty cautious about it but yeah so 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 gosh 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.

[289] And what is it not associated with?

[290] It's not associated with measures of human disturbance.

[291] Whether or not the forest had been subject to a bit of logging or how many people live nearby, that sort of thing.

[292] The chimpanzees don't care about that sort of stuff.

[293] They're living their own lives, and their social dynamics are concerned with what's going on in their own species lives.

[294] So why is a preponderance of males in the attacking?

[295] Is that just a matter of outnumbering the enemy, or are there other factors at play?

[296] Outnumbering looks the important thing, yes.

[297] Right, because they won't attack.

[298] The chimps generally don't attack outside their boundaries unless they clearly outnumbered.

[299] those that they are targeting, correct?

[300] And that explanation for that, they have a rudimentary sense of number or amount, something like that.

[301] Is it number or amount?

[302] They have a rudimentary sense of that at least.

[303] Yeah, they're very smart.

[304] 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.

[305] And what this comes down to is eight males attacking one.

[306] It's not 16 males attacking two.

[307] And so in this average system, when eight males attack one, here's what can happen.

[308] 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.

[309] And they do.

[310] 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 but you know 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.

[311] But the chimps that attack are so smart and figured 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.

[312] So they know what they're doing.

[313] And this is the imbalance of power hypothesis that what is 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.

[314] Inbalance of power is enough to induce attack.

[315] So, you know, for me, this is this is classic Lord Acton.

[316] Power corrupts, an absolute power corrupts, absolutely.

[317] And so what's in it for the attacking chimps?

[318] What is it that they gain?

[319] They don't gain immediate food.

[320] They don't gain immediate females.

[321] You know, they don't walk back to the communities with a kidnapped female or anything like that.

[322] They don't show in the next few days increased acquisition of fruit from a tree on the boundary, nothing like that.

[323] But what they do gain is increased confidence in moving in an area that was previously more evenly used between the two communities.

[324] So they decreased the probability that they're going to be someone who's one against eight it's partly the safety problem like that but 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 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 individuals that are able to occupy a larger area reduction in the time between births for those females.

[325] So the females are feeding better, the males are feeding better, and even increased survival of the offspring in that community as a whole.

[326] And how much killing does it take to produce such effects?

[327] I mean, is the elimination of one or two individuals from a neighboring troop sufficient to do that?

[328] Like, what scale does this have to occur at before those consequences emerged?

[329] Anyone know?

[330] In those two best known cases, in one case, all of the males in the neighboring community were killed.

[331] I see.

[332] So it was complete obliteration of the competitors.

[333] It was initially a small community.

[334] There were only seven males in it.

[335] And they were all killed.

[336] I shouldn't say they were all killed.

[337] I should say they all died.

[338] And in four, maybe five cases, they were known to be attacked and killed.

[339] And so is that typical, is the typical behavior to move in those situations towards complete elimination?

[340] Do we do it?

[341] It's typical.

[342] And it may well not be.

[343] I mean, you know, if you've got a very large community neighboring, then I can well imagine that they kill several.

[344] and it just means they are able to dominate an area that was previously more evenly shared.

[345] So in the case of the Ugandan story, Etangogo in Kibali National Park, you had something over 20 kills that were made 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 or that was of the of the neighbors it's unlikely than any neighborhood communities were completely eliminated though those are those are immense communities that that killer community at that time had 25 fully adult 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 a number of communities that had a large number of males.

[346] But they were probably the biggest boss on the block.

[347] So you were working with Goodall when that initial raiding behavior was documented?

[348] Yes.

[349] I mean, I saw some of the first raids.

[350] That's no wonder you wrote your first book that were inspired to do the work to write your first book, which was demonic men.

[351] males.

[352] I mean, that must have really, I mean, that, that's quite a bombshell that, that discovery.

[353] And like, Goodall was, if I remember correctly and informed him correctly, Goodall was quite hesitant about sharing those results for some period of time, I believe.

[354] Is that, have I got that right?

[355] Or was she just being cautious or what, what's the story there?

[356] Well, I don't think that's right.

[357] Oh, okay.

[358] You know, it's funny.

[359] William Boyd wrote a book called Brazzaville Beach, which was obviously inspired by what happened in Gombe.

[360] And in that case, the protagonist, the sort of Jane Goodall figure, was very reluctant to share the results.

[361] And I think that that may have affected the popular understanding.

[362] But no, Jane, I mean, in 1979, she published a paper that was describing some of these results.

[363] And I think she's always had a...

[364] a very faithful and honest approach to presenting this.

[365] She didn't hide it.

[366] Yeah, well, I wasn't, I wasn't, I certainly wasn't suggesting that.

[367] I mean, I can imagine, though, that a scientist in her position would want, what would you call, to be damn sure of the proposition before releasing it on the world.

[368] Well, fair enough, yes.

[369] And, no, I mean, she's, I think she's been appropriately cautious.

[370] You know, she described what was seen.

[371] I think I probably did go a bit beyond her in inferring the more general tendencies.

[372] But by 20 years later, 96, when I published demonic males with Dale Peterson, I think it was pretty clear what was going on.

[373] And then, as I said, another 30 years later, the data were really coming in very solidly.

[374] And I mean, in some ways, I wasn't too keen on the type of demonic males because it's a little bit in your face.

[375] I wanted to make is that it is very extraordinary because we only know two species on earth, or at 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.

[376] and those were chimpanzees and humans?

[377] Yeah, well, when I picked up the book, I mean, 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 scholarly examination of this proclivity.

[378] And so for people who are listening who are interested, it's a very, very solid book, and it isn't, it isn't, but accessible 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 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 your work with with jane goodall and and and that that's setting you up for for the long -term study of chimpanzees?

[379] Well, I mean, I actually studied feeding behavior when I was working with chimpanzees.

[380] 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.

[381] The, just the daily search for food, you know, people, when they come to film chimpanzees, They often are expecting to see tool use or dramatic sexual behavior or something exotic in their first day or two.

[382] And they say, this is so boring.

[383] You know, they're spending six hours a day just sitting in trees eating.

[384] Yeah, well, I think it was in the book Catching Fire, maybe.

[385] Is it in that book, do you document, is it in that book that gorillas, that the documentation of guerrillas spending up to eight hours a day doing nothing but.

[386] chewing leaves.

[387] That's right.

[388] They have to do that because their diet is not particularly rich, and so they don't have time for much else.

[389] And with chimps as well, it takes a lot of calories to keep a chimp going.

[390] And so that's also perhaps offers some insight into why it took human culture so long to explode in the way it does.

[391] It's very difficult to get beyond hand -to -mouth living.

[392] Yeah, I just think it's a really helpful sort of embedding of of the reality of animals' lives.

[393] And it's not something necessarily comes across when you read about their social behavior.

[394] But they are spending most of their time strategizing about how to get as much food as possible.

[395] And I found that immensely helpful, but on the other hand, it took me a long time before the penny dropped.

[396] You know, I actually tried to live like a chimpanzee, a little bit in the sense of eating what chimpanzees ate you know I ate everything chimpanzees 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 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 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 these animals being hungry all the time.

[397] And it's difficult for us to get into that mentality because we are never hungry.

[398] We can satisfy off our food needs all the time.

[399] Right.

[400] So we underestimate how relevant that is by a massive degree.

[401] I mean, your book, Catching Fire was striking to me. I suppose in almost the same way that my encounter with the data showing that chimpanzees went on raids, I mean, you made the claim, for example, that well, you think human beings have been using fire for about two million years, which is an awful long time, well, in some sense.

[402] It's longer than I had longer than many suppositions.

[403] 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 intestinal system, our digestive system, and that that's provided us with the additional calories necessary to expend some resources on brain power, more resources on brain power.

[404] Have I got that right?

[405] I hope I'm not doing your book and injustice.

[406] Absolutely.

[407] No, that's all right.

[408] And the other big thing that it did is to hugely increase the amount of time we can spend on things other than choice.

[409] Right, right, exactly, to free us up to to do nothing long enough to think about something other than immediate food acquisition.

[410] Cooking softens food and it softens it so much that we can spend just a fraction of time chewing compared to any of our ape relatives.

[411] So if we were eating our food raw, we would be spending probably more than six hours a day chewing our food.

[412] And as it is, we spend less than an hour a day chewing our food.

[413] So that saves us five hours a day.

[414] And gosh, you know, that is important.

[415] It has different importance for females and for males.

[416] in terms of how females and 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 um a 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 hunting, but also politicking, visiting people in the neighbouring camp, chasing women in the neighbouring camp, and so on.

[417] And the contribution to cultural production, artistic production, aesthetic production, bead -making, all of that, that's all.

[418] Exactly.

[419] That's right.

[420] I mean, you know, all of a sudden you have a totally different attitude to time from other people.

[421] Right.

[422] You have some of it.

[423] Exactly.

[424] Right, right.

[425] And so, so two million years ago, so what were our ancestors like two million years ago when they discovered fire?

[426] And how it, you know, I'm thinking, how has that come about?

[427] 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.

[428] You know, if I, I, I spend time at my parents' cottage, and I used to bring my little kids up there.

[429] And, you know, adults, human adults will sit in a circle and look at two things.

[430] They'll look at infants and little kids, like intently, watch them nonstop, as if they're eternally interesting.

[431] They don't habituate to that.

[432] But we also don't seem to habituate to fire.

[433] And I'm wondering if, you know, two million years ago there was a mutation that occurred, that made someone.

[434] 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 was endlessly fascinating so I don't know what you think about that idea but no there were probably various kinds of adaptations psychological and physiological adaptations to being near fire to being drawn to fire and so on but I think they would follow the discovery of being able to control it and just how useful it was.

[435] Exactly how that happened, I don't know.

[436] I mean, you know, my personal fantasy goes along these lines.

[437] You've got Australopithecine, so that's like a chimpanzee standing upright.

[438] It's got a big jaw and eating raw foods, big teeth.

[439] It's about the size of a chimpanzee.

[440] And it's clear that there was increasing evidence in the fossil record of meat eating.

[441] And how that comes about, who knows?

[442] 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 just do a steak tartar on it.

[443] and so my fantasy is that they were eating more meat they were using rocks to pound the meat sometimes sometimes they would 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 relationship to their activity and this would happen often enough that out of this would learn they'd learn the opportunity to leave meat near a fire and taste the value.

[444] How often are animals, edible animals trapped in grass fires in Africa?

[445] You know, people often refer to that idea, but I don't think it happens very often at all.

[446] I don't believe there's any studies in which people have actually documented a number.

[447] most animals are able to escape by borrowing underground or running away from the fire you know it's conceivable that that is the way it happened that it happened often enough that people you know figured it out that australopithines figured out what was going on you know it's all speculation as to how fire was first controlled but but i think what is clear is that once it was first controlled, it would have had huge effects.

[448] You know, we know that all animals like their food cooked compared to eating it raw or all that have been tested.

[449] So, you know, not just our domestic animals, but wild animals too.

[450] All the apes, for instance, prefer it cooked.

[451] They just haven't figured out how to cook it.

[452] And how do you account for that?

[453] Seems very strange that how is it that that could possibly be the case.

[454] Like, why do animals prefer cooked food?

[455] It's because what cooking does is essentially predigest food.

[456] And animals like their food as much digested as possible, because the more of digestion you can have done for you, then the less you have to do it yourself, there's a major cost.

[457] Right, well, I can see that it makes sense.

[458] I just can't see how they would have possibly developed the taste for it or the odor preference or any of that.

[459] I mean, do you don't come to come, I mean, is it in some sense like partially decomposed food?

[460] Yeah, maybe with that a little bit.

[461] So, you know, softness.

[462] I mean, in general, animals like their food soft because harder food is tougher and you're going to do more chewing.

[463] So there's a texture issue.

[464] There's a texture issue.

[465] And probably the taste, you know, as you say, a little bit of decomposition.

[466] So if proteins have been partly denatured, then you have more exposure to the amino acids that have a bit of sweetness to them, have a bit of umami flavor.

[467] And all of those are indicators to, even to an ape, that the food is relatively going to be relatively easy to digest.

[468] Right.

[469] It's bioavailable and ready for use.

[470] Yep.

[471] Right, right, right.

[472] But actually, no one has tested the spontaneous interest in the odor of cooked food, and that's something would be really fun to do.

[473] Mm -hmm.

[474] Well, it's certainly a striking characteristic of human response to, especially caramelized meat, which has a particularly distinctive and delicious odor.

[475] Yeah, right, right.

[476] So, you know, this is still an early science.

[477] 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 that I and my colleagues have done, you get indications of 30, 50 % increase in the number of calories.

[478] I mean, this is huge, you know.

[479] Right.

[480] Five percent more milk out of their cows, you know, they're a millionaire.

[481] And now we're talking, you know, some tens of percent.

[482] Right, right.

[483] Essential, a doubling of available calories.

[484] And you also pointed out not only the caloric improvement, but the radical decrease in the amount of time.

[485] takes to do the processing, like the chewing.

[486] Right.

[487] So yes.

[488] So this would be really big.

[489] And I think what it, I mean, the reason, the argument that I make about why this happened surely at two million years ago is kind of twofold.

[490] One is that everything fits at that point.

[491] So that's the point in which you see smaller mouth, smaller teeth, evidence of smaller guts to judge from the shape of the ribs and the pelvis.

[492] and, by the way, for the first time, a commitment to sleeping on the ground because for the first time you have a construction of the organism, the human, in a way that is not easy to climb trees.

[493] Ah, so that made it possible for us to not have to climb trees.

[494] That's the idea, at least in part.

[495] Yeah, the Aristotelpsines could climb trees, so they surely were slept in trees.

[496] But humans nowadays, 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 Australopithian could.

[497] So they'd have to sleep on the ground often.

[498] Well, you have to be nuts to sleep on the ground if you don't have fire to protect you.

[499] So I think that all points to why it makes sense that fire was first controlled around 2 million years ago, literally about 1 .9.

[500] and the 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's 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.

[501] You get a variation in two size, but generally it's declining, but no big things.

[502] Okay, so, so we've, we've, we've touched on autobiographical issues.

[503] We talked about your work with Goodell, we, we touched on demonic males and the rating, and now we've, we've touched on cooking and fire use.

[504] So maybe, because I want to get to your third book before we run out of time, too, you, you, you, you, got really, really interested in aggression, particularly aggression among males, and the particular forms it takes in human beings and our close relatives.

[505] 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.

[506] And that's a fascinating issue in and of itself.

[507] So maybe maybe we could talk about that.

[508] You distinguish first between two kinds of aggression, proactive and reactive, a classic distinction.

[509] So do you want to start there and then elaborate out the thesis?

[510] Is that a reasonable way of approaching it?

[511] It is.

[512] So yes, absolutely.

[513] So the goodness paradox is the title of this book.

[514] And it refers as a paradox to the fact that humans are so extreme with regard to aggression and non -aggression.

[515] 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 no other species, no other mammals, do.

[516] And in a way that horrifies us in retrospect often, and makes us drop our jaws at our own behavioral possibilities.

[517] Yeah.

[518] I mean, you know, the, we're still living in the shadow of World War II and the Holocaust.

[519] 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.

[520] So, you know, there's that that angle on humans.

[521] But the other angle, which it makes human behavior so paradoxical is that we are the kind of.

[522] and most tolerant and most gentle of animals.

[523] And people since the ancient Greeks have said, well, like a domesticated animal.

[524] You know, we meet strangers, we're so nice to each other, we don't have automatic aggression, but nothing like wild animals that...

[525] We share food and make that the basis of many of our social interactions?

[526] Yeah.

[527] 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.

[528] And so, you know, the famous debate between Hobbes and Rousseau, as people put it now, you know, Hobbes takes the naturally aggressive perspective and Rousseau takes the naturally kind perspective.

[529] And this goes on.

[530] I mean, there was a book recently published by a Dutch historian called Ronald Bregman, who's called Human Kindness.

[531] saying, well, actually, humans are spontaneously naturally kind.

[532] So, you know, it's absurd in retrospect to think that people are trying to arbitrate between these two views, that one is correct or the other is correct, because they're both right.

[533] 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 tenancies and you mentioned this division between two types of aggression are 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 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.

[534] Well, the short story is this.

[535] 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.

[536] Right.

[537] That's planned.

[538] That's multi -party.

[539] That's organized.

[540] It's social.

[541] It's one group against another.

[542] Yeah.

[543] And it follows exactly the chimpanzee principle of imbalance of power.

[544] 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.

[545] So, you know, the killers of the Jews and the gypses and the homosexuals and the Holocaust very, very rarely got any.

[546] push back.

[547] They were butchers.

[548] And that's the nature of proactive aggression.

[549] 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.

[550] And part of that circumstance is that we're defining the entities upon which that aggression is afflicted as outside what constitutes human.

[551] Because within the human definition, and all the standard rules of morality apply.

[552] 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.

[553] You're right.

[554] 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.

[555] 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.

[556] Right, right.

[557] And that's very common.

[558] Well, and 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.

[559] You can enter into a social contract with them with implicit understanding, whereas with an outsider, you don't know what rules apply.

[560] And so their behavior isn't predictable, and they don't obviously fall within the overarching definition of moral.

[561] And maybe that's what underlies the definition of human in some sense for us.

[562] Yeah, I mean, that seems like a reasonable explanation.

[563] But the net result is that even a total stranger in a completely weak state, the first thing 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, and let's find out your morals.

[564] It's a kill him.

[565] Right, right, right.

[566] So, you know, I say this because there's a romantic view that among small -scale people, particularly Hunters and Gables.

[567] gatherers, there is this extension of generosity of spirit to people of different languages.

[568] And you can argue very strongly against that.

[569] So let me ask you a question that just popped into my mind about that.

[570] I mean, it's a compelling idea.

[571] I know that in the, I think it's in Genesis in the Abrahamic stories, there's tremendous emphasis.

[572] on the hospitality that has to be shown to a stranger.

[573] And so that seems to be an exception to that general principle.

[574] And so I think it's a definition of a stranger that's the issue.

[575] 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 the larger series of Judaic tribes.

[576] Right, right.

[577] So still in, still encapsulated within the idea of what constitutes the central people.

[578] Yeah, okay, okay, okay.

[579] Well, that could well be.

[580] I mean, 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 groups still and so forth as our groups got bigger and bigger.

[581] Well, and maybe we got some more.

[582] We all one world.

[583] Right, right, right.

[584] Well, at least we, yeah, we do that to some degree.

[585] The automatic enemy is horrendous.

[586] Right.

[587] So you really have to think yourself back into a very different past to understand this.

[588] So that's all proactive aggression.

[589] The proactive aggression, the use of power to damage anyone outside your group.

[590] And then the reactive aggression that you describe is also characteristic of many, many other animals who engage in male -to -male -male conflict.

[591] So that's not unique to human beings.

[592] And that involves emotional reactivity.

[593] It's impulsive.

[594] It's immediate.

[595] It's defensive.

[596] That's right.

[597] It's all those things.

[598] 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 just human taught and that sort of thing.

[599] And even though there's very important cultural elements to it, it's part of our biology.

[600] But reactive aggression is what people, you know, if you look up aggression in a textbook canal behavior, it's almost all about reactive aggression, often exclusively about it.

[601] So reactive aggression is testosterone -fueled.

[602] It's losing your temper.

[603] As you say, it's impulsive.

[604] It's motivated by anger.

[605] Not only by anger, but anger, frustration, shame.

[606] It's associated with emotions, that's right.

[607] And what's striking about humans is that we are very down -regulated for reactive aggression compared to our close relatives.

[608] 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 magnetism.

[609] 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 we know we're way down the scale in reactive aggression and the same time way up the scale on proactive aggression and the goodness paradox is a story of how did we get this astonishing mixture and I think you know we have actually have a really good story for it now, a really good understanding.

[610] And it, uh, 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.

[611] Yeah.

[612] And I, I know there's literature.

[613] I interviewed Richard Trombley on this YouTube channel.

[614] I saw the podcast.

[615] Yeah.

[616] Oh, okay.

[617] 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.

[618] It's only about 5%.

[619] And virtually all of them are male.

[620] 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.

[621] And those are the ones that, well, you have a story about them, I think.

[622] Well, I mean, I think that's 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 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 what I'm saying our earlier ancestors, I'm thinking very specifically of what happened around 300 ,000 years ago.

[623] So this is when we get the first glimmerings of our species moving into sapienization.

[624] Sapionization, process of becoming homo sapiens.

[625] People now say it started about 300 ,000 years ago, that's thanks to fossil discoveries in my own.

[626] Morocco, and that's when you first start getting smaller teeth and smaller mouths indicative of a trend that will get increasingly strong.

[627] 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.

[628] 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.

[629] were sapiens compared to our earlier phases.

[630] But not necessarily any loss of cognitive power.

[631] 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.

[632] And I think you posited that that was a consequence of decreased size of the brain areas associated with reactive emotions.

[633] That's part of it anyways.

[634] Yes, you may be extending slightly beyond what I said, but I actually do think that.

[635] That's right.

[636] It seems to me that there's quite a bit of evidence that part of the contribution to brain size is associated with reactive aggression.

[637] And so, you know, bonobos are less reactively aggressive than chimpanzees.

[638] They have smaller brains than chimpanzees.

[639] Females are less reactively aggressive than males.

[640] Females in a whole bunch of species have smaller brains.

[641] domesticated animals all have smaller brains than their wild ancestors and there's even some very provocative evidence that if you give testosterone to humans then 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 obviously we domesticated domesticate animals.

[642] And there were wild hypotheses like some sort of super race that had domesticated this all and then disappeared.

[643] And these were very early speculations.

[644] But you have a hypothesis about how this might have come about that doesn't involve such what would you call extreme speculation.

[645] Yeah.

[646] And it comes originally from Christopher Boehm, who was an anthropologist who went to look at chimpanzees.

[647] 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.

[648] And when that happens, there is a consistent solution.

[649] Because you have to think about societies in which there's no police.

[650] There's no one to help you.

[651] You're just on your own in your society.

[652] And here is this guy who is being incredibly objectionable and may actually kill other people.

[653] 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 despot so in the end he gets killed now that's what happens nowadays and what christian and 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 emerged the advantage of physical strength is decreased substantially at least in principle is that 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.

[654] There are very nicely preserved spears from 400 ,000.

[655] Right.

[656] I'm thinking more about weapons used against the bully.

[657] Well, yes.

[658] But, you know, animals without weapons can kill others and quite safe.

[659] Even nowadays, you have descriptions of humans killing without weapons.

[660] So how much weapons really mattered is unclear.

[661] You can kind of argue it both ways.

[662] But either way, what you see in the present is the argument that is taken back into the past.

[663] 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 the way 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.

[664] That's why no other primate has escaped having an alpha male bully.

[665] Only humans have converted an alpha male bully into an alliance of males, among whom there is a sort of formal level of equality.

[666] And if anybody in that alliance tries to throw their weight around, they know what will happen.

[667] They will get taken out as the bully originally did.

[668] So you paused in the goodness paradox that there's been enough of that in human societies over the last very long.

[669] period of time to have markedly decreased the propensity for reactive aggression to such a degree that it's also transformed our morphology and our and our psychology at the biological level right right and you know it probably accelerated over time the loss of reactive aggression the move towards this domestication -like species that we are now 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.

[670] 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.

[671] She would come along and say, I don't want to mate with you.

[672] And he would say, too bad.

[673] And punch her chosen male in the face and take her off 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.

[674] 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.

[675] 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.

[676] It documented the lives of villagers, a very isolated and archaic Japanese village.

[677] And there was a group of villagers, a family of villagers in there that consistently broke the rules and pilfered food.

[678] And all of the villagers conspired together as a consequence of that.

[679] and in the night crept into their house and killed all of them.

[680] It's exactly the scenario you describe.

[681] It's an unbelievably striking movie.

[682] I saw it in a repertory theater.

[683] I really like to know, I'd really like to know the name of it.

[684] 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.

[685] and one woman goes voluntarily and the other fights and struggles and it's a horrific scene.

[686] 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.

[687] It's the only thing I've ever seen like that.

[688] Yeah, I mean, I haven't heard of that movie, but I can cite you a number of cases nowadays, even in Texas, where similar sorts of things happen, where you get isolated communities, where the police are in our, adequate and people just take it on themselves.

[689] But the case you mentioned is not quite like the one I was mentioning, because it involves people being punished for pilfering food.

[690] But it, it's not, that's right.

[691] It's more it's breaking, it's breaking the moral code to be a variant of that.

[692] Yes.

[693] 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.

[694] So 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?

[695] So is what happens that the conspiratorial parties define the bully?

[696] as a consequence of his behavior, as non -human, and are then able to use their intrinsic proclivity for proactive aggression to target him.

[697] Yeah.

[698] Yeah, I mean, whether they define it as non -human, that's, you know...

[699] 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.

[700] 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 violating your moral code.

[701] Well, I have some accounts which are that they say it's time to send Bert or whoever back to the witches because he looks like a witch.

[702] 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.

[703] 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.

[704] We are the domesticated version of the species that lived 300 ,000 years ago.

[705] 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.

[706] So they are the supreme dictators as a group of what is okay.

[707] 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.

[708] But sometimes the rules will not be good for everyone's 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.

[709] Or the bachelors will not be allowed anywhere near the women or are choice pieces of food.

[710] 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.

[711] That is a really good place to bring this discussion to a close.

[712] We covered a tremendous amount of material today in the last 90 minutes or so and touched on the three, your three books.

[713] I'm going to repeat their titles for everyone so that people who are interested can read them, which I would highly recommend.

[714] Maybe I'll let you do that because I've lost my notes here.

[715] I want to get the titles right.

[716] So the first one was demonic males.

[717] Demonic males, apes on the origins of human violence, 1996.

[718] Yeah.

[719] And then catching fire.

[720] Catching fire.

[721] How Cooking made us human?

[722] 2009.

[723] And then the goodness paradox.

[724] that's a strange relationship between violence and virtue in human evolution, published in 2019.

[725] Well, thank you very much for talking to me today and for walking me through that and the audience that I have no doubt will appreciate this through it as well.

[726] 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.

[727] So I hope everyone else feels that way as well.

[728] And maybe we can get a chance to talk through some of these things.

[729] I'd be interested in hearing more from you about your ideas about how more complex political structures might have emerged from this initial, say, consensus against violence, something like that.

[730] Yeah, that's a very interesting developmental historical idea, I suppose.

[731] So anything else you'd like to add to close things off?

[732] Do you want to have another hour and a half?

[733] Yeah, well, that would be nice.

[734] And we'll do it again.

[735] I'd like to do that again.

[736] Maybe we can talk together with Franz de Wall if I can convince him to do that.

[737] That might be fun.

[738] That would be interesting.

[739] Yeah, all right.

[740] All right.

[741] Well, thank you very much.

[742] Thank you so much.

[743] My pleasure.

[744] And thanks again for agreeing to do this.

[745] It was a pleasure talking to.

[746] Pleasure meeting you.

[747] And thank you for your books.

[748] I learned a tremendous amount reading them and enjoyed it very much too.

[749] So until we meet again.

[750] Okay.

[751] All right.

[752] All right.

[753] Bye -bye.