2020 Paul D. Bartlett, Sr. Lecture - The Relationship Between Virtue and Violence in Human Evolution

uh it's a pleasure to be back in Kansas I just wish it was real rather than metaphorical uh thank you moderators and thank you everybody for uh for attending uh I'm here to to share what I think of as a report from the front uh about new ways of thinking about really two problems in human evolution one is the one that is in this title here uh the Odyssey about our species that on the one hand as represented on the left of the screen were exceptionally cooperative and tolerant uh strangers can meet and have very pleasant interactions and on the other hand we have this tremendous capacity for violence that's one kind of problem the clash between those two things and the other is about human evolution how did we get here how do we have a fine specimen of humanity namely the president of Harvard on the right emerging from a species that we might call homo heidelbergensis on the left uh represented I don't know whether that's the president of Princeton or the president of Yale but um one way or another we have this this curious end point to human evolution that we're still trying to to understand how did we get to where we are today the way I'm going to organize this is to first of all talk about the Paradox itself the Paradox being that on the one hand we are exceptionally violent on the other hand we're exceptionally cooperative then I'll talk about the two kinds of um approach to understanding this that we are very I'm calling virtuous uh very limited in our aggressiveness in some ways how do we get that and on the other hand what has the role playing of violence in our human evolutionary past and then we'll wrap that up and think about the evolution of homo sapiens very briefly at the end I want to point out that this is not a story about human evolution in general because it really is a focus on males so for the the most woke among you I apologize in advance for the fact that um we will hardly mention uh females at all this is a story about aggression and the principal source of aggression in our species is of course males and we see that in contemporary World um it continues to be a real bother to us uh how on the one hand uh mostly we can organize our lives in ways that are very peaceful but we can get these eruptions of violence that are so deeply disturbing as in Kenosha here so there's the Paradox on the one hand exceptional non-violence on the other hand exceptional violence let's just look at these uh a little bit and see why it's a problem the problem is that the ordinary way that we think about aggressiveness is on a single scale that a species might be rather unaggressive a species might be relatively aggressive but somewhere on that scale from left to right and if we have that single scale we have the problem that on the one hand we have uh apparently a tremendous tendency for reduced aggression compared to a lot of species I'll go into this a little bit more in a minute but this is the the essential view represented by uh Jean-Jacques Rousseau the resilient perspective is that we are are born in a very unaggressive State and we tend to be corrupted by Society if in fact we end up being more aggressive and then on the other hand there is the view that we have an evolved tendency for competition and violence and aggression uh represented most commonly by Thomas Hobbs from the chaos of the English Civil War and um in that case you have the view that we we are born in sin as it were and we are civilized by Society so those are the two views and it's very difficult to see how we can be at both ends on the scale of aggression um but there is uh in fact a very simple solution that is amazingly taken a long time to emerge and that is that there is not a single scale of aggression there are two types of aggression and they're represented here uh there is the proactive and the reactive the instrumental and the emotional and these have been recognized for a long time in biology they've been recognized for a long time in Psychology for decades uh they're applied very usefully to Children if you're thinking about uh problems in in school they're applied to criminal investigations they're applied to a Psychiatry and Psychotherapy and we know a lot about them in terms of the way in which the brain controls aggression of these two types and the two types are the proactive aggression which is planned aggression it's where somebody is not necessarily emotionally uh engaged but uh they feel an aggressive uh plan that they design in order to achieve a specific kind of goal and it may be to punish someone for wronging you it may be to acquire something it may be a moral wrong you see it represented by various awful kinds of episode here from lynching to genocide to to killing a disaster that's proactive aggression it happens in animals it happens in in humans a lot and then there's reactive aggression which is where you lose your temper there's a sudden initiation a man comes back and finds his wife in bed with another man and within seconds he pulls out his gun and and kills maybe the man maybe the woman the aim is to uh get rid of this immediately provocative threat and I've put in a picture I'm in the bottom right of somebody putting their hand up as if to say I don't want to get involved and that's just to be a reminder that what we'll see is there's a reactive aggression occurs is it relatively low rate in in humans we have a low propensity for it well back to proactive aggression this is the type that clearly predominates in war planned aggression where one side plans to drop bombs take out a Machine Gun Nest go on a raid into the neighboring territory and that is where the source of most deaths come in this figure I've shown some of the data from various different kinds of society about the rate of death the percent of population killed in war per year and you see the full left-hand colors the foragers farmers pastoralists and industrialists represent different societies each each column is a different society and you see a lot of range of variation in the rate of killing over the few decades that people were recording but overall um it is quite high and I'm going to show you what I mean by quite high in the next slide but let me first draw your attention to the fact that the chimp range is in the similar range to the human ranges now let me show you what I mean by quite High look at these industrial um societies uh there are actually five there one is so low you can't even see it represented and the other four are lower than the foragers or the Farmers or in The Chimps in general but the remarkable thing is that those include data for most of the 20th century for countries that went through both world wars and it reflects the fact that even though we think of that as a particularly awful time which of course it was in terms of the total number of people killed in terms of the percentage of the population that was killed it is actually not that high the humans overall do have a very high rate of death from proactive aggression compared to any other species and I think that comparison with what we clearly see is a a high rate from the point of view of individual experience um in the in the two world wars that shows how high in general humans have been and then there's reactive aggression well here is a picture of some ACE hunter-gatherers uh foragers in Paraguay and they were studied by Kim Hill and now it's 43 years that he has worked with them and he's never observed them scuffling at all losing their temper to the point of getting physically engaged is a very rare thing in human society and it's it's often something that will turn up in the news of course if people get into it literally a physical fight um the situation is very different when it comes so what you see in this video is a pretty intense aggression it's the kind of thing that if it was seen in humans when Pearl Beginnings the newspaper but it's more of a daily occurrence in chimpanzees and just emphasizes a huge difference between ourselves and our close relatives it's true from bonobos as well by the way that uh bonobo is the peaceful cousin of chimpanzees has a rate of aggression still something between a hundred and a thousand times as frequent as humans when we're talking about reactive aggressiveness so I think we can regard the Paradox as solved it's not paradoxical when you recognize that human aggressiveness comes in two forms there's reactive aggression and there's proactive and we have a low propensity of reactive aggression compared to uh our relatives the chimpanzees and the Nobles whereas we have a high preventative proactive aggression uh compared to most species although chimpanzees also have a hydro density okay well now what do we do with this solution what I want to do is to investigate why it is that we have such a low propensity for reactive aggression which is what I'm going to be calling virtue and the key to the answer here I think is the concept of self-domestication so our low propensity reactive aggression represented here by one of the most unaggressive animals I can imagine the lopier rabbit or a domesticated rabbit gives us the opportunity for individuals to interact together in a very calm way to be very tolerant to each other and to be cooperative things which are really fundamental to the existence of homo sapiens and many people have regarded this kind of combination of characteristics as fascinatingly similar to domesticated animals basically what time what time in the same way that a dog is tame compared to a wolf we have a low propensity for reactive aggression the father of physical anthropology as you sometimes called the German Johan blumenbach was the first to say explicitly that humans are far more domesticated than any other animal but lots of people listed below have said this sort of thing in principle that that humans are like a domesticated animal now interestingly we can then move to thinking about the anatomy and whether or not human anatomy is similar to a domesticated animal and the way to think about this is uh the way to um to to how you identify a the bones of a fossil or a domesticated animal if you are an archaeologist Digging Up Bones in the last say eight or ten thousand years and the answer is that if you look bottom left here and think about the aurox which is the species of angular that gave rise to a cattle you find a skull and you want to know was it an aurox or was it a domesticated one a cow and the answer is look at these four characteristics listed above does it have a relatively light body is it got a short face and small teeth as the skull and skeleton being feminized with the males looking more like the females now and has there been a reduction in the size of the brain and if they those things are true as you see in the picture on the right then it'll be a domesticated species as in the modern cow compared to the skull of the aurox there well what archaeologist Helen Leach did was to observe a few years ago that in their Anatomy humans unlike domesticated animals because when we look at the skeleton and skull of homo sapiens compared to The ancestral species in the genus homo we see the same features humans have got Homo sapiens have got a lighter body shorter face small teeth the skull and skeleton have been feminized and remarkably in the last 30 000 years we got a reduction in the size of the brain now to put this in the sort of context of of human evolution here is a scheme to show the evolution of the genus homo so if you look at the bottom line uh two million years ago 2.0 you've got the emergence of homo erectus the first species of the genus homo that could walk into a shop on Main Street and get clothes off the peg it was the shape and size of modern humans or in that variation in that range of variation and then you've got various species and we'll focus on the ones on the right when we're rectus becoming homo Heidelberg against us and then about 300 000 years ago you get the earliest species of homo sapiens the earliest members of the homo sapiens species identified by having a relatively short face small molars and a reduced brow Ridge which is a male feature that is now getting feminized here is that brow Ridge you see it as we move from left to right from 300 000 years ago maybe dated on average at 315 000 years ago this specimen from Morocco and then you come to uh recent uh skull and you see the prior ridges largely gone and the faces have become narrower too and this is fascinating because it's a phenomenon that is associated with reduced aggression men's facial width will face the width of the face in relationship to the the height from the eyebrows to the upper lip is coronated it turns out with aggression and I put up a picture of hockey players here to uh illustrate this with a study of professional hockey players as shown here and uh in the same paper a study of college hockey players where you see exactly the same result as you see here the result is based on the way that hockey players get punished for losing their Templar if they are too aggressive then they are confined to the Penalty Box for a number of minutes by the referee and the more aggressive then the more time you spend in The Penalty Box what you see here is the amount of time spent in The Penalty Box for six different teams in relationship to the width of the face the relative width of the face and some of these relationships are statistically significant on their own and some are not there's a lot of variation you can't predict for any one man how much time he's going to spend in The Penalty Box based on his width of his face what you can say is that in general the men with wider faces tend to spend more time in The Penalty Box and this is just an illustration of the fact that uh there is this astonishingly persistent correlation with wider-faced men tending to be found to be more aggressive as I say if you personally on wider faced it doesn't mean that you personally are going to be more aggressive but this is on average so that's an example of a relationship between aggression and Anatomy that is just very intriguing here overall on the human similarities to domesticated animals we have a low frequency of reactive aggression we have anatomical changes in our case for 300 000 years that have been similar to the changes that you see in domesticated animals they are associated with reduced aggressiveness in animals and in humans it seems and then something I just very briefly talk about we can now start seeing evidence that there are genetic associations with reduced aggression uh and the same anatomical changes so here is an example of how we can get out some of the genetic changes domesticated animals have certain features that crop up repeatedly not in every individual but repeatedly an example is the white toes and the white Blaze that you get here in horses and dogs and cats and pigs and this is rather the equivalent of the short facing small teeth and the reduced body size and the reduced brain size and feminization that you get in domesticated animals compared to their wild ancestors well uh this particular feature of the white toes and Blaze is something that has given rise to an investigation of the genetics underlying domestication why is it that in these different lineages you get similar kinds of features emerging in the domestication syndrome whether it's outside or inside the body and the answer that is uh suggested by some including myself is that there is a change in the genetics of a very early tissue that appears in the very early embryo the neural crest and it turns out that when you have a genetic change that leads to a reduced migration of neural crest cells from the back of the body outwards around the body then the ordinary pattern of pigmentation doesn't work so this figure that you see here imagines the way in which the neural crest tissue shown in blue comes out from behind the spinal cord and then spreads around the body it's an absurd picture because it shows it in adult animal it should be in a tiny little thing that's smaller than a pinhead but um it's illustrating the the point that the neural crest carries or or moves around the surface of the body and it um carries all sorts of implications for the emergence of adult organs well one of the things it carries is the pigment cells and if you get reduced neural crest cell migration either reduce speed or reduce number of the neural crest cells and the pigment cells arrive too late at their terminal sites in other words the end of the legs the end of the tail the end of the face and you've got a white patch there because there's no pigment oh well that's um the kind of thing which is beginning to show a tie between the genetics all the neural crest and some features in the domestication syndrome and here is another one a gene called bac1b is on chromosome seven you can see it's per location uh in the figure on the right and in a very recent paper this has been shown that when you have reduced expression of this Gene it leads to a delay in the movement of the neural crest it occurs in domesticated animals uh not in the wild it occurs or the these are these new versions of the the gene occur in Homo sapiens compared to our close relatives the Neanderthals and the denisovans whose genome is now been able to be looked at from fossil specimens and uh in uh humans there is a syndrome called the Williams Buren syndrome and they have uh this change in the expression of ba z1b and is associated in that case with calm temperaments and reduced aggressiveness so we're beginning to get a picture of a serious genetic changes that occur in domesticated animals compared to the wild animals responsible for the tie between uh reduced grossness and changes in the anatomy the overall conclusion here is that we're dealing in homo sapiens with a species that does not merely like a domesticated species in its behavior and like them in anatomy but so like them with the genetics coming to support this that we actually are a domesticated species and that means we have to be as optimisticated species because nobody else did it for us so we see this increasingly domestic like Anatomy for 300 000 years signaling reduced aggressiveness ending up with our a lopier rabbit Behavior today so there's the picture uh the idea is that the earliest Homo sapiens seen at 300 000 years ago are just beginning to show the kind of anatomy that becomes exaggerated as we come forward in time to the present day and this Anatomy indicates that that was a time when reactive aggression started to be reduced and we would call ourselves the beginning of a self-domesticated species so the great question about that then is why how would this remarkable event have happened and that's significant not only in making us less aggressive but also in producing the species that we call homo sapiens so here we've got a 300 000 year old reconstruction reconstruction of a 300 000 year old male based on the broken Hill uh skull from from Zambia and uh and the question is what changed to make them self-domesticated so think about this I want to go to talking about the pattern of dominance that emerges among males in ordinary primates and the answer is very simple in every group of chimpanzees Orba logos or baboons or macaques all of these group learning primates there is a single alpha male and he becomes the alpha male by physically beating up all his rivals he is helped sometimes by his Rivals he is helped sometimes by females that happens in bonobos and in bonobos he is not necessarily dominant to all the females he may be subordinate some of the females but in all of the primates the alpha male is one who is individually able to beat up on his rivals and I suspect this would have been true for all of the species of homo prior to homo sapiens at least we know that in Homo sapiens it is not true we don't have that alpha male system now of course we talk about alpha males in humans in a sort of joking way but let's think about what actually happens with the dominance hierarchies of humans on the one hand you have small scale societies the type that we all lived in our ancestors all lived in until 10 or 15 000 years ago and in those the relationships among adult males are described as egalitarian on the basis of the fact that there is no physical Alpha there is no Alpha in other words who can individually beat up on all of the other males I might try occasionally but it doesn't get anywhere and then you have state societies and here we again have hierarchies now we do have hierarchies in which you can clearly say that not everybody is equal you have a president you have a king you have a prime minister but those hierarchies are not the result of Boris Johnson or Donald Trump or Juan Carlos individually beating up on the individuals below him in the hierarchy he achieves his status by being political by using coalitions and then Things become very complex the important thing is that we have a different kind of system from the primates now I said that every now and again in a small scale Society you do get somebody who challenges the system they're meant to be egalitarian but sometimes you get somebody who just throws his weight around who might grab some meat that comes in when somebody has been working all day out in the bush and finally comes struggling home with the results of their hunt and then this guy takes it from or who is his way into taking men's wives or who just makes them feel bad or who kills men who get in his way this has happened there are many ethnographic reports of them but the same thing happens every time you try as a society to deal with it reasonably they ostracize them they ridicule them who do you think you are big boots they might try walking away just getting up in the middle of the night and leaving but of course that's no good because the kind of spices we're talking about people are very good at following each other and they can they can just never really get away so if there is somebody who is disturbing the social calm in a really serious way making everyone else feel bad and maybe being life-threatening to them then there is an answer and it's always the same one and that is the ultimate sanction is execution Christopher burn is the Anthropologist who is done most to pursue this uh line of reasoning and observation through the small-scale societies of the world and here is what he concluded he said the typical domination episode involves a male who seriously intimidates people at the level of lethal threat and then is dispatched by his own Kinsmen with the approval of the group and the reason for that being their own Kinsmen is because if someone who's not Akin is involved in the execution then there's a danger that there will be Revenge killings because the kin are feel kind of obliged to support their dead relatives now this uh pattern is understandable in a world in which you don't have police you don't have an army you don't have a state you don't have anybody to call on except yourselves and if somebody is using their physical strength their weapons their loudmouth to make life appalling for everybody else then there is ultimately only one thing that you can do and the idea is this that the regular application of execution to deal with the original kinds of alpha males that would have been there physically bullying their way to the top the chimpanzee like males executing those individuals now thinking about humans would lead to selection against their genes and their genes would be for reactive aggression these are men who lost their temper When anybody challenged them and this would lead to a domestication-like event in 1932 worried about the oncoming threats in Europe Einstein and Freud had a well-known correspondence and Einstein asked Freud how can mankind prevent war and Freud in his answer was the only person until very recently who suggested why it is that humans in general have evolved to be non-violent from a reactive point of view the original state of things he said was Domination by brute violence and he was citing very new studies at that time of gorillas and baboons and he was thinking of the way those males get to the top and then he continued the path that led from violence to right or law is it the superior strength of a single individual is rivaled by the union of several weak ones that's what we're talking about that's the way that an original alpha male in the very earliest stages of homo sapiens could be defeated by a group of individually subordinate males males who are scared of that Alpha didn't want to be beaten up by him and they come together and talk about it and develop a plan to get rid of execute that alpha male and this is a unique feature in humans and the thing that's unique about it is not that there is a coalition because primates have coalitions the thing that's unique about it is that the Coalition is directed at a chosen Target who is planned in advance p-a-c-t proactive aggression directed as a chosen Target when Caesar's assassins decided to kill Caesar it took a lot to make sure that they were really agreed and even when the event happened they had to egg each other on it takes a lot to have the courage for a group to kill and individually dominant individual but humans can do it and the reason that they can do it is because we have language sophisticated language and it's going to be very sophisticated given the delicacy of the situation enables us to float an idea with a colleague and say you know there's only one way to deal with this guy and that is let's get together and kill it chimpanzees can't do that two pounds is can get together in small groups and kill members of neighboring groups but then there's no decision about who to kill everyone knows it's the enemy but in humans they can decide that a member of their group is going to shift from Ally to victim and the important point about the fact that people can get together and plan the killing is that it means they can choose to organize the killing at a time when they have overwhelming power and the victim is totally undefended low-cost coordinated lethal punishment which still happens today when people are executed so here you have I think the origin of social control by adult males what Freud was referring to as right and law and even now as is we have the same sort of thing occasionally happening I don't know if any of you come across this there's a remarkable case of um a man called Ken McElroy who bullied his way to the top of a village hall at home small town called Skidmore by 400 people in Missouri and eventually he was killed in front of a whole bunch of witnesses and no one was ever brought to trial because there was coordinated agreement we don't talk about this he had bullied his way he'd taken people's daughters as his wives his houses and gun barns who killed pigs he shot two people uh he was an extraordinarily um repentful man and the village decided the town decided that there was only one way to deal with him and I think what they were doing was going back into our past as it were to do it so what I've argued is that the way to think about the mixture of of human goodness and Badness is that our goodness comes from our having a very low propensity for reactive aggression while violence reflects the fact that we have a very high propensity to use proactive aggression in a coordinated way if we think it pays which it does in war and it does in the context of executing those who make our lives miserable and of course what you see here is our capacity for proactive aggression being responsible for our reduction in reactive aggression so thinking about this in terms of human evolution here I would characterize an old view of human evolution which is to some extent still true hear what we see plotted is a measure a likely measure of intelligence which is the cranial capacity this how much room there is inside the skull plotted Against Time coming increasingly to the present and we go back to the eight-ply costalopythe scenes between two and three million years ago and then we start getting into humans and we see a rise in the size of the skull and many people have thought that this is enough to explain the evolution and origin of homo sapiens that the result of increasing brain size was increasing intelligence as we did that we were able to make better tools we had more cultural and civilized ways of organizing our societies uh summarized as more brains less Broad so the the reduced robustness physical robustness of homo sapiens compared to earlier species was simply the result of we don't need it because we could think of other ways to dominate our our landscape we didn't need to just be physically strong there may be something in that but what I've suggested is that there's something very special that happens when you get language and I don't mean the origin of language because probably neanderthals had some language probably homo Heidelberg against this handsome language but when language became sufficiently sophisticated that individuals can whisper to each other some very dangerous thoughts about hey what if we tried to use each other to kill that ghastly guy who's taken our wives and killed our friends when it got to that point something happened we entered a new unique world where humans for the first time could cooperate in ways to kill individuals that were individually physically dominant to them and then you get a lot happening and here I'm suggesting that once you have that cooperation based on language you can have capital punishment it will lead to a reduction in reactive aggression it will lead to us becoming like domesticated animals and one of the ways in which that happens is that we've become better Cooperators and become more tolerant and out of that we get what we would call modern behavior which I'm thinking of modern behavior here as the behavior of homo sapiens long time ago ten thousand twenty thousand years ago increasingly modern as we come towards the president we have gone on to other things Homo sapiens out competed all the other homo Homo erectus neanderthals the denisovans all the other homo have gone we have Diversified into a species that has colonized the whole planet we even threatened to go into outer space and that was all dependent certainly on our intelligence but I think it also depends a lot on our ability to tame ourselves to the point where we didn't lose our Temple so easily we could cooperate and be a better kind of human thank you very much and now we're going to transition to a panel well I'm Steve kraske I'm with kcur public radio and uh University of Missouri Kansas City let me introduce our panelists here tonight to be able to react to What Richard had to say to us today uh on my far left Christopher beard is the distinguished Foundation professor in the ecology and evolutionary biology department at the University of Kansas Dr Beard studies the origin and early evolutionary history of primates and other mammals Chris it's nice to have you here tonight thank you also with us Jennifer RAF is an anthropological geneticist and an assistant professor in the anthropology department at KU her research centers around the understanding of human prehistory through analyzing the genomes of ancient and contemporary populations Jennifer it's nice to have you too well Jennifer I'll just begin with you um I don't know about you but I'll never look at a wide-faced male again in quite the same ways I have in the past but what do you think of Richard's Theory here in which he attempts to explain how it's possible that men can be both virtuous and violent all wrapped up in one package so I think it's a really interesting Theory I think there's a lot to this that I find points of agreement with I do differ slightly on some on some of the underlying science there as one might expect you can't get a group of scientists together and expect them to agree on everything um one of the things that I find a bit troubling is um the association with between um morphological features and behavior I find a lot of the studies that one looks at in the record scientific record are fairly weak actually in their associations um and the wide face that kind of well yeah I I know and we can we can chat about this a bit the specific some of the specific literature that you cite but for example there's one study where you look at UFC fighters mixed martial art artists not you but the authors look at them and it's actually a pretty terrible study I've got to say um speaking of somebody who's been immersed in the Mixed Martial Arts world for quite a long time there's a lot more complexity there that is not captured by examining comparing photographs of individuals faces to their win-loss records um so in general I find a lot of um concern relying too heavily and to to directly on the literature from evolutionary psychology where a lot of the studies tend to be quite weak they have small sample sizes and often over interpret their results but I do think that you do he qualifies his his research quite well and I appreciate especially in discussions of genetics and talking about the warrior Gene for example and how the the effects of the warrior Gene as we see are often overhyped and in fact it is extremely context dependent and extremely culturally dependent how that behavior is expressed Chris would you react please yeah well uh I mean you know it's a big challenge especially when you look at the fossil record to try to tease Behavior out of the fossil record that may be the most challenging thing that we Face uh as paleontologists and paleoanthropologists on the other hand uh I mean it's a basic guiding principle of evolutionary biology that one of the best ways to try to understand ancestral conditions is to look at the living descendants of a common ancestor and try to try to kind of perhaps using just simply parsimony try to tease back what that ancestor might have behaved like now of course that's a that's a method that's fraught with all kinds of difficulties as well if you have some fossils that can shed light on perhaps what that ancestral condition might have been like then that that can certainly help um but uh but yeah get I guess my biggest question is how confident can we be about the nature of the common ancestor between chimps and humans that's a really interesting question Professor rangan why don't you react to What both Chris and Jennifer are having to say here okay um well let's see if Jennifer was troubled by the um the putative association between morphology and behavior um and I I certainly accept the one has to be very careful here um I had more time I would have shown um slides of the uh meta-analyzes of the relationship between uh facial width and uh and various kinds of aggressiveness and that would take us into a discussion where uh I'm sure Jennifer would persuaded well I don't know if she persuaded but um except that there are some weak studies but um and I accept them meta-analysis which is analyzes where uh people assemble uh the independent results from a whole series of different data sets even those can be wrong but I think the thing that's that persuades me that there is something to the relationship between morphology and behavior is the result of experiments I didn't have time to talk about today where people take a wild animal and deliberately breed for reduced aggression and then see that there are anatomical changes as a consequence and this has been done with um boxes uh mink rats chickens and mice and you get these anatomical changes as a consequence of selecting against aggressiveness so that seems to me to be uh very intriguing support for the kinds of correlations that I was talking about yeah but but I certainly accept Jennifer's point that you've got to be very careful and um the science I think we'll we'll get better as we as we go forwards Professor Rangers I think it's still very good with regards to the the animal studies Professor rangham those changes you just mentioned are they detectable within one generation or two generations in what you're describing to us yes no that's excellent um the textbook um over a longer period um by 10 Generations that sort of thing um but uh clearly the longer you go on then the more detectable they are um there are remarkable ones that are being um found now with um domestic and not the domesticated animals with the urban animals uh where they're reduced um aggressiveness to humans it would seem has led to anatomical changes that mirror what you see in domesticated animals that doesn't answer your question but the important thing about your question is um it's more than more than 10 Generations I wanted to get some context here as we continue our conversation I mean Jennifer it strikes me that Professor rangham is departing from some prominent thinking you know Darwin being among them can you put his views in context for us how original are they how big a departure are they and what he's saying what do they represent oh I think that uh his views accurately represent a um a new way of thinking about human evolution that is as fairly common among a subset of of human evolutionary biologists um as far as the historical context well he does a very good job in his book of giving that context for us um in that there were differing perspectives among the early evolutionary biologists about the nature of of man because of course they all talked about man only um and and and his propensity to violence versus his propensity to um to more pro-social behavior and I think that it is certainly only recently that um this notion of self-domestication has really taken hold of a subset of evolutionary um anthropologists and evolutionary biologists I wouldn't say that it's probably the most predominant one yet um but it is certainly quite a quite a strong uh cohort there Chris what would you how would you uh describe this yeah I pretty much agree with what Jennifer is saying I I think that uh I mean back in the day several decades ago when I was in graduate school nobody talked about humans being self-domesticated um so people interpreted the human fossil record more along the lines of that traditional their brains are getting bigger Through Time faces getting smaller Etc I think that the I mean the the distinction between reactive and proactive aggression that Professor rangham really uh makes a big point about I think is a really important one because clearly I mean he is a grade eight behavioral ecologist clearly the behavior of living chimpanzees as we saw in the video clip is radically different from the behavior of living humans and and the the real question then is exactly how did how did those changes occur through Evolution from a common ancestor that we shared which really wasn't that that long ago talking seven eight million years ago that we had a common ancestor so something really happened in between and and I think this is a really good framework to investigate Professor ringham how surprised should we all be that we're still seeking to understand this most basic and such a provocative question that you're asking here of how human beings can be both aggressive and virtuous why are we still wrangling with this today well I mean it's amazing because uh you know you could have asked [Music] if asked me could have asked the question how amazing is it that we should be asking about what's responsible for the origin of homo sapiens um and so what's amazing is that you have to step back a bit to realize how recently science has been addressing these very fundamental kinds of existential questions the first hundred years after Darwin produced the original species and you know the first well-worked our devolutionary Theory were really spent not on thinking about applying them to humans but on working out whether or not this was true whether or not the theory was right and of course by the middle of last century that was shown it was right um but still the uh application to humans has been fairly slow to come after that and part of the reason to that is that the fossil record is still developing it's um you know astonishing to realize that one of our closest relatives their dinosaurs were only discovered uh was it two decades ago or nurse so it's a very um ongoing field it's not that major theories have been proposed and wiped away it's more that we are I would say building uh on a sort of somewhat gently developing framework you know this idea Jennifer is yeah interesting about that this idea that we're gradually eliminating from society proactive aggression through various forms of capital punishment one thing I wondered is are there enough uh cases of of man particularly being eliminated through capital punishment to result in the broad sweeping behavioral changes that Professor rangham is talking about here well that's an area you can call me a skeptic and for sure um I'll respect to Professor ringham but I I think it boils down to humans are bio-cultural animals we're not just biological animals and I think that it's extremely important that we acknowledge the influence of both culture and biology in our behavior and that is something that distinguishes us from chimpanzees from bonobos quite a bit um in addition to the fact that we have been engaging on this evolutionary trajectory separate from both bonobos and chimpanzees our own trajectory it makes it um concerning to me to draw simple parallels between them and us although certainly there are areas that we can look to them for in order to understand our own behavior our own Evolution we have to be very careful about reductionism and when it comes to genetics and and and driving human evolution and human behavioral Evolution through selection um and this is a type of I imagine artificial selection right the removal of violent individuals from by execution um there has to be if it's selection there has to be a genetic effect and unfortunately we do not understand the genetics underlying human behavior underlying violence as well as I think many people think we do it's very enormously compact complex and we need to be cautious in how we talk about this Chris do you share Jennifer's caution here honestly uh I mean my perspective is probably one of a broader perspective in terms of time and taxonomy I'm not a I'm not an anthropologist um I mean what's interesting to me about human evolution which is probably counter-intuitive to most of the members of the audience uh in in Victorian England people taunted Darwin and Huxley by talking about missing links you know there must be a missing link if humans are really have really evolved from an ape-like ancestor where is the missing link where's the missing link well 20th century biological anthropology has provided us with a whole series of missing links on that human lineage from about seven million years ago up until now we've got a huge number of fossils now that illuminate that particular part of human evolution good thing we're not chimpanzees because there are there are a huge number of missing links in the chimpanzee fossil record and and I mean essentially the chimpanzee fossil record is nil um and and that actually I mean it's it's hard maybe for us to think about this but in many ways uh additions to the chimpanzee fossil record would probably tell us a lot more about our own deep ancestry than yet another australopithecine at this point um so that's one problem yes they're missing links but they're not where we think they are um I guess the the question about uh about modern human behavior and how is it different from Modern chimpanzee behavior is it relatively recent because of this self-domestication event and Homo sapiens or is it something that has that has occurred in stepwise fashion across those seven million years that we're talking about to me that's a bit of an open question and maybe it's a mixture of both I am in intrigued by the fact that as far as we can tell the earliest australopithecine fossils that we know about already show a reduction in canine dimorphism so males don't have these giant canines that chimpanzees still have I don't know what that means but it's classically been interpreted as some sort of reduction in uh at least intramural aggression in in early australopithecines so uh so it could be it could be that we're looking at at a long history that then gets punctuated with the evolution of language I I don't know I mean I'm just kind of riffing here but that would be my my idea at least or a hypothesis I'd love to hear what Professor Adam please weigh in here what's what's what's your thinking well I totally agree that um we have to be cautious about the behavior of homo prior to Homo sapiens and the self-somestication event that I think is identified by the changes in anatomy that occur at the origin of homo sapiens um could well have been preceded by other kinds of self-domestication happening maybe with the origin of homo out of Australopithecus maybe with Australopithecus out of a chimpanzee-like ancestor um those are difficult questions um there is one specific point though I would just uh um sort of balance uh Chris's point about the reduced canines in australopithe scenes with um the the male Australopithecus uh I I think it's fair to say most analyzes now um seem to have been substantially larger than females and so I I think uh well the interpretation I give in my book and fits with a number of people's is that the reduced canines are all to do with the change in diet which means that a gate in the mouth was relatively little and they didn't fight so much with their teeth and that change in diet would have been needing to chew much harder than happens in um primates like chimpanzees and the chewing would have been because they were eating roots in the more open Savannah and the chimpanzees eat um that that's an analysis that is uh supported by comparison with carnivores and ungulates so that species that have to chew more have um mouths that open less and therefore less opportunity for the canines to get along and be used as weapons so I suspect that there was still considerable aggressiveness in the male Australopithecus based on the apparent degree in body mass of the two Sexes um and the robustness of the homo prior to Homo sapiens sure makes it look as though they were pretty intimidating individuals um but uh it'll be great to know more about bone breakages and other indications of how often they were involved in episodes of aggression that would have left some kind of signal we can find in the fossil record you know I'm just wondering maybe as a final question Professor rangham this idea that it's such a profound idea that we are moving away from proactive aggression which will be uh potentially great news to so many people if we can continue uh this this in this direction what are the practical ramifications of what you're coming up with here can the process be speeded up I mean is there anything hopeful you can you can offer us that might lead us to a better tomorrow the kind of aggression that seems to be biologically reduced to judge from the changes in anatomy is reactive aggression making us a species that is um increasingly tolerant of each other from the point of view of immediate loss of tempo as well the proactive aggression I wouldn't say there is any evidence of [Music] well there's no direct evidence for a reduction in a propensity for proactive aggression you can certainly concoct a story that it might be being reduced because psychopaths are individuals who are given to proactive aggression more as well as reactive aggression and you can certainly make a story indicating that there's been seduction against psychopathy which might have been a feature more of our earlier ancestors well the big picture but proactive aggression is that we are still a species very willing to use it startingly scarily willing to use it and I gave those examples of genocide and lynching and killing disorders and you can find uh evidence of products of aggression used to kill [Music] all over in every society this is where Jennifer's point about the importance of culture really comes in because um the the way in which species and doesn't matter whether I talk about humans or other animals use proactive aggression is to make sure when they conduct it that they have very little chance of themselves being killed the proacts of aggression it's a classic example in humans is the raid which is carefully planned leads to some deaths of victims and then the aggressors scoot back to their own side that kind of aggression has clearly led to a tremendous number of deaths over the human history but uh Stephen Pinker in his book the better angels of our nature pointed out the actual rate of deaths has been declining a really remarkably steadily I mean some variation certainly but um but it has been declining over the last centuries uh and Millennia to judge from all the evidence and the reason it's been declining is the cultural one that we have developed institutions we've developed social Arrangements that make it difficult for the potential aggressors to envisage that they can get away with being aggressive so I think the hopeful aspect is to say that we are on this path in which uh our institutions are better and better at um enabling people to anticipate that if they use their power to be proactively aggressive then there will be consequences and the result of that is that people are less likely to be proactively aggressive you can say that this is the fundamental logic underlying the fact that there has been a peace among the most powerful nations in the world since the evolution of the nuclear bomb because there is very likely to be a swift comeback to those who use it it doesn't mean that we are not still living in tremendous Danger but it does mean that uh if we can develop consistently systems that mean that proactive aggressors are themselves very likely to suffer from launching attacks on their victims then it's less likely that the attacks will be launched in the first place Chris what's the hopeful uh takeaway for you from our presentation here today yeah the hope I think is that is pretty much as Professor rangan laid out that Humanity can rise above biology and and you know an overcome what probably was something approximating you know nature red and tooth and Claw and the pleistocene I mean the uh you know one of the things that's interesting to me is that there is this kind of Duality between scientific data and Analysis of that data so for example a number of decades ago uh at kind of the dawn of genomics there was a study that uh that got promoted in the press as mitochondrial eve and the idea was that that human evolution went through a bottleneck a genetic bottleneck in Africa perhaps between one and two hundred thousand years ago and that and that all living humans are descended from this mitochondrial eve so when the study came out um Stephen J Gould Harvard said oh this is fantastic because this shows the inherent Unity of all of humanity where all recent descendants of the common ancestor uh let's start singing Kumbaya another biological Anthropologist who I'm not going to name at the same time said we're all descended from a single common ancestor that recently tell me it's not true this means that our direct ancestors were were these demonic Amazon women that ran out of Africa and killed every single last one of the poor neanderthals and they were our direct ancestors so this just shows that you know you can you can interpret scientific data almost however you want and kind of project it however you want um I think that that's that's a serious danger in in studies of human evolution but as everybody has pointed out we are cultural animals we can rise above our biology I think that's the hoop how about you Jennifer I agree with what both of these gentlemen have said um I would also add to that that we just need to cultivate among the public a healthy skepticism of simplistic answers to complex questions especially as those that concern us um and and make a plug for the as as both of you have also mentioned um the importance of our institutions in in keeping our behavior um regulated for the good of our species well Jennifer RAF Chris beard both from KU thank you so much for your time today Professor Richard rangham what a pleasure to have you with us thanks for taking the time from Way Beyond where we are we sure appreciate your time today thank you very much Steve thank you Jennifer and Chris thank you thanks a lot for more information about other Linda Hall programs go to lindahall.org [Music]

Channel: Linda Hall Library

Views: 1,825

Keywords: anthropology, biological anthropology, violence, evolution, human evolution, science, engineering, technology

Id: nlHiZ3HO6ds

Length: 67min 26sec (4046 seconds)

Published: Tue May 09 2023