Planet of the Humans: The Leap to the Top

[Music] [Music] [Music] [Applause] [Music] [Music] [Applause] [Music] [Applause] [Music] [Applause] [Music] [Music] [Applause] [Music] [Applause] [Music] [Music] [Applause] hi everybody I'm Brian Lehrer from wmic thank you so much for coming tonight wasn't that dance number sweet I loved how the robot manipulated the human into thinking she was still relevant no that's not what it was about oh I'm sorry I was specially impressed that the robot fell on its nose something it might have learned from me watching when I was out running in Queens last weekend and then splat I figured I should just explain why it came out with bandages on my nose and that's why so maybe what it means to be human is that when we get injured in a visible way we get self-conscious about it while other species don't my mother says the upside of my injury is that now I can get a nose job and insurance will cover it which means my mother was self-conscious about my nose even before I got hurt we are very human we humans before we get out I'll bring out our guests I thought maybe you all might like to get to know a little bit who's here in the audience with you how many of you work in any field you would call the sciences so those are the obsessed people who can't get enough how about humanities or the arts the well-rounded contingent this year business anyone work in business I won't tell your colleagues on Monday I promise and what about crime who here works as a criminal just making sure you were all human enough to lie and not raise your hand if that describes you for all the Charles Darwin contributed to our modern understanding of the biological world one puzzling question which he ultimately posed as an open research question to the scientific community nagged him until the day he died how did the incremental process of evolution by natural selection suddenly produce an utterly unprecedented kind of animal such as humans this program will examine from a variety of perspectives what it means to be human so now I'm going to introduce the participants our first participant is a professor of anthropology at Florida State University she's done research on primate brains and prehistoric human relatives including Albert Einstein's brain and the skeletal remains of an eighteen thousand year old hobbit-sized human welcome Dean fog our our next participant is a professor of psychology at Harvard University he is an experimental psychologist cognitive scientists linguist and one of the foremost writers on language mind and human nature Steven Pinker [Applause] [Music] also with us tonight is an associate professor in the department of biochemistry and cell biology at Stony Brook University he has worked on the human uniqueness problem for over 25 years and he co-authored the book death from a distance and the birth of a humane universe welcome Paul Bingham thank you and our final participant a paleoanthropologist researcher and Explorer his explorations into human origins on the African continent Asia and Micronesia have resulted in many new discoveries including the most complete early hominid fossils ever discovered welcome Lee Berger all four of our participants have different theories we'll see how they intersect and don't and Dean I gather you're gonna start by taking us back 3.5 million years yes thank you I'm very glad to be here tonight I do want to begin 3.5 million years ago and look initially at what archeologists have found in the fossil record and the that relates to material culture and technology and if you go to the left there that little hominin is 3.3 million years old from Ethiopia and you might recognize the fellow on the right he died in 1955 and what I'd like you to notice is a material culture in between three point three million years ago we have the first known stone tools that were deliberately made and for a long time after that what you have in the material record are rocks they get better they get smaller and more modified but as you come up to the present you get your wonderful art much more recently and then today you know we have dancing robots so the question is tonight how did we get from the rocks to the dancing robots and I think it was to do with brain evolution and so what I'd like you to notice now is we're going to see brain size coming in across here so brain size got bigger and as it got bigger it became modified and reorganized and rewired and we know that by comparing brains of humans with non-human primates we know the size got bigger by looking at fossils now ever since at least Darwin people have wondered well who's responsible and what was responsible for this remarkable evolution and there have been a number of theories a few which are very well known one is this is from the 1960s man the hunter and it's still in textbooks it's been very very dominant but within a decade there was another alternative proposed by some of my colleagues who it will not surprise you were many of them women women the gather and there's no doubt that hunting and gathering were extraordinarily important during our evolution because that's how our ancestors made their living up until about 12,000 years ago so for millions of years they did this but I don't think hunting and gathering were the thing that moved along brain evolution and so tonight I'm going to propose someone else baby the trendsetter and specifically I'd like to suggest three trends in chronological order that happens in natural selection on infants very young infants even fetuses and to do that we have to go back another three and a half million years even earlier and look at the origins of walking on two legs or bipedalism and so what we have here is a nifty animation of a quadruped ed becoming bipedal and the colored part is the pelvis that becomes modified and becomes essentially a constricted and millions of years after this that will be a problem for giving birth it's called the obstetric dilemma but we won't see that problem this far back in time but let's play this again and look at the feet so our ancestors maybe as long ago as 7 million years became upright walkers and it completely modified the body and it changed posture and locomotion that foot seems to be a grasping instrument and became a weight-bearing instrument and this is where we get the first trend of three trends in baby the trend setter which is a trend for being a late bloomer so to look at these trends we compare we look in the fossil record but then we compare living humans with living chimpanzees and so you have the direct and the comparative evidence and we know if you see all of the monkeys and the Apes the children or the infant's grow up very quickly they develop all the milestones can hold up their head can crawl eventually stand very quickly human infants are slow their late bloomers they're slow developers and one of the most dramatic things that happen as a result of that is that unlike all of the other higher primates our our infant's lost the ability to cling 24/7 to their mothers the monkeys and apes those babies are born helpless but very soon in their life they can hang on to their infants and during evolution there was a reversal so our babies can't do that they want to hang on but they can't so there was a trend to seek contact Comfort and you see over in the right you see the infant crying and another one gesturing to be picked up and these are advanced trends that evolved humans cry in a unique way that babies have emotional tears and a lot of this studies have shown is because they want the contact comfort with their caretakers with their mothers and we see evolution today that shows this trend which we still have and when you give babies pacifiers or blank 'if you are satisfying their need for contact comfort and that they inherited from their ancestors we also jiggle them and bounce them up and down and that simulates contact with being with the mother being carried along so again you can see the day out there in the world evolution beam why do you think the reversal in evolution happened and maybe talk a little bit more about what you mean by reversal and what would have been adaptive about that - what kinds of conditions at that time okay I think it happened because with bipedal isn't the entire motor system rearranged and it wasn't just feet hands are genetically linked and posture and so babies became Health helped us in terms of locomotion not other things so much and they lost that ability to cling to the to the moms and as a result of that it opened up I think a vocal channel between mothers and infants and we have we see this today - we have mother Eve which is an evolved thing the other primates don't do it they might have contact calls but with human species you know all over the world parents from when the baby's born they speak to in baby-talk and it's incessant and that is a derives a drive advanced feature and it's very important for the acquisition of language in the infant's this eye leads to the third trend I call it the brain spurt and to do this we were comparing humans with chimpanzees and you're seeing a graph here of individuals growing up and what happens to brain size in the chimp at the bottom one that brain size you know this levels off pretty soon with the human there's a spurt of brain growth in that first year and actually prenatally that lifts that graph higher and higher so humans end up as adults with brains that are three to four sizes the brains of the chimpanzees if you look in the fossil record this is one fossil it's an infant from about two two-and-a-half million years ago and you can see its trend is higher than the chimps and if we were to put other fossils on there through time you if you went up for instance to Homo erectus which is much more recently you would see that curved lift higher and higher so this brainy spurt in infants it was responsible I think for the evolution of brain size during hominid evolution and if we want to know what that was about we have to ask well what's happening to that human brain prenatally and very early on that's not happening to the chimp ring beginning in the last trimester fetuses are tuning in to what they're hearing and they're specifically interested in and tuning in to their mothers voices that's being filtered in the womb and their brains are becoming programmed for being receptive when they're born for language once they're born they on their busy pattern processing both the the sounds and vision and it's aimed at or it's directed at a language acquisition babies when they're six months old can hear the distinction in all of the world's languages they can hear about 800 speech sounds by the time they're one year the connections in the brain have both increased and decreased so that they narrow in on about 40 sounds in their native languages so I think that when we ask about in evolution what was responsible for this I think language was very important because the kind of processing that goes on these networks that become widely distributed are also accessible then for other kinds of activities like dancing robots but you need I think have the language first and then that wiring is available or was available I do think that it was probably language because that's what's going on during that brains they're not hunting they're not gathering they're not making tools they're getting language and that is an either-or theory you think it's not kind of all of those things a good question I think probably language with primary and that once that machineries there you get all that other stuff all right steven pinker do you enter through the cognitive niche yes yeah the the first thing we have to explain about our species is why we are so deeply weird biological standards now there's a lot of debate I think often rabbinical and pointless over whether humans are unique whether you know our language whether the dance of the bees ought to be considered a language and whether a crow puts a stick in its mouth that counts as tool use and I usually stay away from debates over definitions or Rubicon's or dividing lines but if you just look at the extent to which humans do humanly unusual things and the collection of them that you all find in one species you see that we're we're very unusual to begin with and the most salient to me as a psycho linguist we talk I mean here we are we're gonna sit in this room for a couple of hours just listening to each other make noise as we exhale very very few species that would do that and language has universally a number of rather remarkable properties we can use arbitrary signs to refer to tens of thousands of objects and actions and places in the world and we can combine them grammatically so that the meaning of the combination can be computed from the meanings of the individual signs and that the way they're arranged but I don't think that language is the only thing that differentiates us from other species I think if you just graft of language on to a chimp it wouldn't have anything particularly interesting to say and so I think that that language has to be understood in the context of other weird traits of Homo sapiens another one is our yes when is our reliance on on artifacts and technology and tools look around everything that we are now seeing was made by an ensemble of humans is nothing but in its natural state in this room and again universally humans not only making use tools but they make a use of variety of them each tool is made out of a variety of parts requires a laborious process of manufacture and most important we co-evolved with our tools if you we depend on them for our survival you take away the technology of any human group and and it would quickly starve the third ZOA logically unusual trait of humans is that we cooperate with people who aren't related to us to us if you were to put several hundred chimpanzees into a room like this half of the male then riot would break out but but humans do in addition to the tens of thousands of people that have to cooperate to make all of the things that we see we sit quietly in order to achieve some something that benefits all of us and again it's very hard to see examples of cooperation for mutual benefit among unrelated organisms so how do we explain what there at that part if I could ask would that but not be also found in things like bees to use your example or no these are ladies they're not only er bees related they're highly related I mean because of their unusual genetic system more related than than been even siblings a lot of are related by sharing three-quarters of their genes so bees would be a case of cooperation mediated by genetic relatedness and asked to dependent I think depends on the species but yeah so and their other unusual features of mrs. Dean mentioned we have long helpless childhoods we have long lives the male's invest in their offspring parents invest in their offspring we have very we have weird sex lives with lots of sex that's not reproductive and negotiated and varying from one group to another in turn it's customs we eat everything were found in every ecological system on earth from from the Arctic to the tropics so there's no question that we're a weird species and we need an explanation yeah I don't think at there other weird species it's not an evolutionary miracle the elephants are weird in their ways and whales and blue-green algae and so on so I don't think we need anything exotic but we do have to explain what led to the coevolution of a number of unusual traits that are all found in the same species my favorite idea comes from a concept originated by john tooby and herb Devore I'm hoping if I repeat it enough times people will forget that I think that I came up with it but that I will mention that they deserve the credit and think they call it fate the cognitive niche and it starts from the observation but the commonplace observation that in evolution organisms evolve at each other's expense so with the exception of fruit every food item for every organism is the body part of some other organism which would just assume keep that body part for itself and so all organisms need defenses against being eaten shells weapons poisons stealth camouflage in the case of plants chemical warfare irritants and poisons and bitter tasting substances which sets the stage for offensive weaponry to defeat the defenses that organisms have against be eaten more acute perceptual systems speed stealth weapons you know call evolutionary arms race now what's unusual about humans is that we kind of cheat in this arms race by developing ways of defeating the defenses of other organisms not over evolutionary time generation by generation but in real time in our own lifetimes by developing mental models of the environment caused an effect texture of the world around us and manipulating it to our advantage we develop traps that rely on laws of physics on expectations of animal behavior on our intuitions about biology we extract poisons from one organism and use them against another we defeat the defences of plants by boiling or fermenting or peeling or cooking and therefore enjoy plant nutrients and all of it done faster than other organisms can develop defenses in their turn because we do it in our heads and by exchanging ideas with one another which is why whenever humans enter a habitat the other species drop like flies if you look at talk about definitions of our species if you look up man in ambrose bierce is the devil's dictionary the definition indicates that our chief occupation is the extermination of other species and each other however we reproduce with such insistent rapidity as to infest the entire habitable earth and Canada I think kind of CAP captures our species and I think it explains the why the that entire complex of ZOA logically unusual traits is found in the same species because each one of them multiplies the value of the others most obviously there's technology which depends on our intuitive understanding of the environment what breaks what bends what Falls what rolls and that depends on our intuitions of physics of forces and objects and substances our intuitions of living things of organisms that have essences that are responsible for their powers I think it accounts for our language that if we have accumulated technological know-how that gives us something to talk about something to share and it means that we can profit we don't have to as they say reinvent the wheel but we can profit from all of the strokes of genius and trial and error and accumulated wisdom of other members of our species but only if we're cooperating with them that is only if we have something to offer in the expectation of a return farther down the line and of course language is also the medium by which we can negotiate reciprocal exchanges we don't just have to exchange you know meat for fruits or or groom one I groom you then you groom groom me with language we can say I'll do you this favor now but you know as with the the opening scene of The Godfather the there there will be a day and that day may never come where I will ask a favor of you and I expect you to remember what I did for you today something that you can only do with language the thing about language is that it exchanges a unusual commodity information that's unlike other trade goods because it can be multiplied at virtually no cost if I give you a fish I no longer have the fish but if I teach you how to fish then it's not as if I'm now I'm music for the ability to fish we both can have it I've made a copy of it and information can exist in any number of copies which makes it a perfect trade good because the theoreticians who try to explain the evolution of reciprocal altruism say that it's powered by the ability to confer a large benefit to someone else at a small cost to oneself which is what makes the reciprocal exchange mutually benefit beneficial information has that property language is an efficient way of exchanging information if you're on speaking terms so all three of them I think reinforce the other two so it sounds like you're describing some of the characteristics of human uniqueness how much would you say the cognitive niche might come from baby the trendsetter the Dean was talking about how much do you overlap in this and how much are they mutually exclusive yeah III think there is overlap I would have less confidence in singling out one part of this complex as the the first domino but but I do think they all reinforce each other and certainly our long you can think of our what why does our species have this long helpless childhood well it's a in part it's an apprenticeship we depend more than other species on acquired know-how uh it before we strike out on our own reproductive career there's a lot to learn and so we are helpless for a long period of time just to acquire in our lifetimes the kind of survival skills that other animals are more likely to have pre-programmed thank you very much Steven Pinker so Paul Bingham tell me how a molecular biologist doing research into the treatment of cancer got involved in this area where as you put it to me backstage what's a nice molecular biologist like you doing in a place like this I actually trained with the generation of people who develop contemporary molecular biology matt meselson Jim Watson Francis Crick and my scientific grandfather was Linus Pauling and and from those people I learned the importance of really good theory but also the importance of waiting to attack a question until it was within reach but what happened in the late around 1980s we began to see where the answer to the human uniqueness question might lie and that brought us into this domain as natural scientists bringing the tools of natural sciences into the project I should emphasize before I began that there are two other crucial collaborators in this project one is Professor Joanne Souza at Stony Brook University as psychologist who's been involved in every aspect of this project for over a decade and professor daijiro Okada originally at the Institute for Advanced Study at Princeton now at UPenn a game theorist and economist who helped us develop the technical game theory that underlies the stories that we're going to talk about in the next few minutes so what we set out to do was to develop what's called a parsimonious theory in the jargon of the Natural Sciences that's a theory that's simple on the one hand and yet predicts a lot in detail these theories are really useful for two reasons one is that they're powerful they let you predict and understand things ostensibly including human uniqueness in human nature they're also useful for another reason because they make lots of predictions and are therefore easily testable if they're wrong you can tell quickly and if they're right you begin to get an idea that you're correct the theory that we have developed is referred to now as social coercion theory and I want to outline it for you in the next few minutes it appears to be one of these highly parsimonious accounts of some of the things that we've just been hearing about it of course it will be very interesting to hear Dean and Stevens reaction citizen so before I begin taking you through the details of the theory let me start right at the beginning by emphasizing that a lot of people are looking for the origins of human uniqueness in the emergence of modern humans symbolized by the image right here very recently let's say in the last 50,000 years on social horrors in theory we believe human this has much greater time depth than that 1.6 to 1.8 million years at least and it follows for example that Neanderthals and modern humans who coexist at 50,000 years ago were equivalently human by any reasonable measurement and we argue that our ancestors largely displaced Neanderthals as a result of a particular kind of social accident that we're going to return to in just a couple of minutes okay so to understand social coercion theory we have to begin at a well documented in fundamental fact about the world all non-kin individual animals have conflicts of interest that's symbolized by the fighting individuals here humans are unique because we are the first animal to control those conflicts of interest moreover we do this in a simple specific universal way through the present instant as illustrated on this slide we we take advantage of the capacity of projectile weapons to allow large cooperative coalition's to inexpensively project overwhelming coercive threat against what game theorists call Free Riders social parasites non co-operators as a result in us for the first time in history of life on earth cooperation between non kin becomes police about an therefore a Darwinian adaptation this as you'll see in the next couple of minutes is a revolutionary transition of course guns are a very recent invention we believe that that practical projectile weapons became available to our ancestors for the first time as the result of the evolution of elite aimed throwing so humans throw with the same kind of virtuosity that a dolphin swims or a cheetah runs our minds and bodies have clearly been redesigned for this specific behavior moreover there's sound evidence which prefer perhaps we can discuss later that elite throwing is at least 1.6 to 1.8 million years old now at first glance of course it's a little disturbing that our access to inexpensive social coercive violence is the origin of our uniqueness but let me argue to you that there is a diametrically opposite and very important perspective to take in us the humane cooperation is a Darwinian adaptation because of the parallel Darwinian capacity to coercively suppressed inhumane behavior so we argue that the evolution of elite throwing is the ultimate cause of all of the other properties a few million acres that we've been hearing about tonight and so let me actually walk you through some of the some of those stories so this slide emphasizes what Dean told us about a moment ago the dramatic expansion of that brain size in our lineage to understand this we have to begin someplace a little unexpected with culturally transmitted information culturally transmitted information is very useful if true but potentially false so its transmission between non kin individuals creates a powerful conflict of interest and an animal can evolve to exchange cultural information between can only if it can manage that conflict of interest ancestral hominids had the capacity to coercively ostracize liars and tools and then that kind of environment truth-telling and the transmission of cultural information now becomes an adaptive Enterprise as a result of this massively expanded stream of cultural information we are of course obviously the cultural information the cultural animal as Steven mentioned a moment ago but this creates an adaptive benefit to expanding the expensive neural tissue that stores and processes that all all that information giving us brain expansion moreover we expect the brain to be redesigned systematically to deal with all this information in diverse ways including the evolution of elite linguistic behavior the quintessential talent for transmitting information moreover we expect us of course to be the pedagogical animal to spend all of the time that we've talked about absorbing this information we also predict that we should be the economic animal we have access to enormous amounts of information but we can't know everything so in fact there's enormous individual adaptive benefit in exchanging the fruits of individually specialized culturally transmitted expertise that we hold with others who hold different expertise of course this creates a conflict of interest problem the exchange of valuable things creates a conflict of interest problem and only in an animal that can coercively enforce some form of property law can the act then can economic behavior emerge our status is the economic animal is going to be very important in a few minutes as we understand how we got to be so ascendant over the last few thousand years we'll call that back in just a moment we also expect that we should be the moral animal in a very specific sense our ethical psychology should look like approximate device to mobilize our participation in conjoint coercive threat moral outrage looks very much like that we should also evolve to engage in cooperative activities that depend on this coercively enforced moral environment as in fact we do there's one last prediction that's less obvious but extremely important we should be are predicted to be the radically Democrat mechanimal throughout most of our 1.8 million year evolution as humans the coercive weapons that were available to us were inherently broadly distributed coercive threat was democratically owned very recently just about 5,500 years ago new technical developments allow the invention of weapons body armor and shock weapons in particular that tended to concentrate course decisive course of threat in the hands of small militarized male coalitions elites unfortunately the social units resulting from that what archaeologists call archaic States invented written language so when we first started investigating this new home Union union's problem a few hundred years ago the oldest evidence we had indicated that hierarchical patrimony was the natural human condition that's almost certainly false and misleading we are in fact almost certainly a radically democratic animal by biological nature that's also very important we'll call it back in a few minutes so these specific predictions sort of illuminate the way in which we can understand social core human uniqueness as emerging simply from the evolution of social coercion but in fact we they and they give us insight into the human condition human nature but we're more confident than just that that the theory is likely to be right because it spins out the first broadly general theory of history that we've ever had and of course the good theory of history is valuable because it's also a theory of the present in the future if it's right so I want correct write that clarify a few things did you say a bit ago that militarization led to speech and language no well it depends on what you mean by militarization democratized forces threat ancient 1.62 1.8 million years ago allow the emergence of kinship independent social cooperation with all of its features including the expansion of culturally transmitted information the evolution of language to transmit that and if we are coercive animals yes then why would we also be moral or radically democratic animals Stephen said before if this was a roomful of chimps riot would break out and then presumably the most dominant and successful ones would you know scare away the others for the future and coercion would have taken place in that species right so there are a lot of different ways to answer that question in arriving at the same place but so it turns out that in non-human animals who don't have this capacity for conjoint projection of threat decisive threat is in the hands of dominant individuals large and powerful individuals but because of the effect of numerical advantage in the use of projectile weapons power doesn't lie with large individuals it allows it lies with numerical majorities it power exists in numbers so in fact we can only be powerful as humans if we are members of a majority coalition so we are coercive but we're coercive of humane behavior in one another property behaviorist even if I heard you correctly it was that the first large hierarchical States were also the ones that develop written language not language I'm sorry I should have hammered the word written Yeah right but that turns out to be really important right because history is the line made up by the winner so in point of fact the in point of fact this written history appeared to present elite patrimony patriarchy as the natural condition and we're arguing that that is most emphatically very unlikely to be true and a few mins learn to control conflict of interest how do you explain Albany sorry I couldn't resist what Steven mentioned the importance of arms race is evolutionary arms races so our control of the conflict of interest problem is constantly being subverted by interest groups and it's a it's a constant back and forth in our ability to manage that so in fact as I alluded to a moment ago we also get a theory of history that emerges from social coercion theory let me take the last couple of minutes to outline that for you because it's extraordinarily important we believe so human adaptive sophistication is actually no longer really limited by our individual intelligence it's limited by the scale in which we can engage in economic cooperation the number of specialists within our cooperative groups however the size of our social cooperative groups is absolutely limited inevitably by the scale on which we can police the conflict-of-interest problem thus our human history is predicted to look and does look as follows humans acquire the scale of cooperation permitted by the course of technologies they possess and then acquire the adaptive sophistication associated with that scale and then remain at that adaptive sophistication sometimes for very long periods of time however for one reason or another ultimately a new weapon is invented allowing an expanded scale of policing of social cooperation and a new adaptive revolution rapidly ensues and in fact this happens over and over has happened over and over again in our history so I alluded before to the social accident of the triumphs of our modern ancestors over Neanderthals there's good reason to believe that that is the result of modern humans inventing a weapon called the OP model - the spear thrower which substantially expanded their extent of their coercive range expanded their social cooperation and then they rolled over Neanderthals for the same reason that European states rolled over Neolithic Native Americans not because they were genetically superior but because the scale of their social cooperation was greater this image is intended to stand in for the agricultural revolutions another set of adaptive revolutions there's very good evidence in Eurasia in particular that the invention of the bow gradually spreads across Eurasia and in its wake numerous agricultural revolutions ensue in the interest of time let me skip the archaic state which we already talked about a moment ago and proceed directly to the modern state that you and I think of as the natural condition with the invention and refinement of gunpowder weaponry it became possible to stabili consolidate the state initially and then ultimately to redistribute access to course its threat democratically this creates now something fundamentally new in human history a social unit that practices the ancient human art of democratic cooperation but does so on the massive new scale of the state we predict and observe an adaptive revolution so for example you and I are about a hundred times richer than our medieval peasant ancestors of just a couple of hundred ago and indeed the Scientific Revolution unfolds the Industrial Revolution unfolds at this same time in just the last couple of generations in living memory we have for the first time acquired the capacity to project coercive threat on a planetary scale as a result of this development we now police in a kind of rough way in the ancient ancestral human way a global cooperation the threat of world war is predictably receding as a result thus we are now irrevocably joined in a enormous coalition of seven billion people and growing the opportunities for human enrichment at this scale are enormous as are the dangers so for example we now have global financial markets that can empower massive projects that are highly vulnerable to elite manipulation and catastrophic instability we can also prosecute science on a global scale represented here by the Hubble telescope and are therefore peeling the layers off the physical universe at a gallop the challenge of course is to use all of this new information sustainably and adaptively we are now locked irrevocably in an exponentially accelerating race between our knowledge and our wisdom I think an opinion that probably we would all share on this stage is that one of the single most important pieces of knowledge we need in order to have the wisdom to build a humane future for all of the world's descendants is to understand our evolutionary origins and its implications for our behavior all of us on this stage and the communities of which we are members are working assiduously to try to provide that knowledge now you come up with a percentage chance that humans are doomed to destroy ourselves through our wisdom being right but insufficient to our knowledge well as Yogi Berra famously said predictions are hard especially about the future but they I think that we I think I'm actually relatively optimistic I think the likelihood that we perish from thermo nuclear holocaust for example is extremely low I think it's more like because in fact we are who have two million years of experience dealing with course if weapons we're good at not overstepping their limits the real danger of course is that we inadvertently destabilize global climate and don't realize it until it's too late our adaptive power makes us very vulnerable to that end thank you Lee burger you've been doing new research I know in recent years on human uniqueness have you views been changing very much well what was ironic when I was asked to be a participant in this planet of the humans was it struck me immediately that well unlike Stephen science my science of paleoanthropology and the biological origins of humans is obsessed with definitions and Rubicon's we have spent a great deal of our time defining what it is to be a species and setting points of moment that we're extraordinary in the past what might surprise this audience although all of us have been speaking sort of Glivec glibly about the obvious nosov human uniqueness is that there is no real biological definition of what it is to be a human we don't have the fine definition in place that allows us to readily say that's a human and in the fossil record this is not a human what happened in the Victorian era when we first began to examine our sort of origins was it was very easy religious texts told us what it was to be a human and we were separate from the world we were separate from the animal world we were different in very obvious ways we stood upright we were more complex we had spirituality we had tools that no other animal seemed to come near we had all the physical features that were all aware of a large brain small teeth we could compare ourselves and Darwin even notices to what he presumed were our closest living relatives in Africa but clearly that difference was substantive it was obvious and it didn't need defining it was already manifestly defined in our history then we began to find fossils now very luckily they fit our preconceived ideas in the order in which they were found and in our expectations of human uniqueness the first ones being found in Europe or large brain but what we would consider crude and primitive in the form of the early Neanderthals that was followed by faux fossils which fit our preconceived ideas even better we even invented them and Piltdown which actually led us to the obvious conclusion that all the important events in human evolution had happened where the highest states of civilization are places like Europe and so we had actually manufactured a fossil record that agreed with our ourselves then we moved that story to Africa in 1924 the discovery of the Tong job that was a small-brained it looked like a biped so it seemed to separate itself out from the world and the fossils that would follow would as they began to gain acceptance show the kind of just so stories that fit the idea of human uniqueness we would see faces low level of brain increased through time eventually we would end up with this large special human brain that went through a series of transitions that were pretty much along the storyline we found out that bipedalism was deep time and utterly made us unique from all other primates and even human level bipedalism when fossils like Lucy came on to the stage it seemed to cement the idea that there it was we were erect and the our hands we could see were prehensile adapted to tools and even the archaeological record supported that we could see that as those changes occurred the idea that brain size increased the hands altered that tools appears so that's why Homo habilis was called handyman in in the beginning of the first idea of the earliest members of our genus that would lead to a progression that we would we would find so clearly to have us ask questions of modernity the idea of what does it mean to be a modern human in that very definition saying that well there's something different between those of us today and those things that might have looked like us but clearly aren't us is that sort of uniqueness that everyone alludes to right now if you look at textbooks or the archaeological record it'll tell you that it's accompanied by some things that are happening probably between a hundred and two hundred thousand years ago closer to a hundred and two hundred thousand that fits really well with genetic evidence which is arguing that all of our we all share very narrow genetic identity appearing just about it that time period that's tied to things like adornment the first art that we're now seen in places like where I work in southern Africa that appears to be tied to perhaps humans seeing themselves as special in nature and that might manifest is burial of the dead except are leading up to what is an on definition of humans that is obvious it's obvious when we see one we just don't know how to put all that together and as Stephen and I were talking before this discussion maybe it's just all of those but the problem with that is that's really moving right back to where we were in the Victorian era we can see it but we can't test it we can't formulate a hypothesis to test it but we need that hypothesis because that neat little story that I was just telling that we kind of saw through a broad timeline of a few million years as as we as we deliberate it is falling apart those sacred cows are dying particularly the last 15 years as what was a incredibly fragmentary small fossil record paleoanthropology is one of the unusual Sciences that up until recently we could probably claim that we had more scientists than we had objects to stay and that probably tells you more about the people who study this sort of thing than it does about the positive of the record but as the fossil record has exploded and quite literally the numbers are doubling on almost a yearly basis now on the continent of Africa as we begin to expand our exploration programs those sacred cows are dying just recently with our deepest thickest ramidus we realize that that bipedalism may have other definitions than this sort of simplified version that we see here have elongated legs and and the changes in structure to our pelvis and our foot and that words like facultative bipedalism come into the record that brain size and and those moments of shift and brain size may be either didn't occur at all or we're not necessarily important for changes things like Australopithecus sediba which my team and I described a few years ago has a small brain but reorganization appears to be taking place things like the Flores Hobbit so that many of you might have heard of this small contentious member of the genus homo on the island of Flores dating to maybe fifty ninety thousand years or something like this is clearly in our genus with a tiny brain the size of a chimpanzee but capable of complex activities so that brain size argument may actually fall away or be slaughtered along with others we're seeing different sorts of of manipulative abilities that are not all the same in the hands and we can go right through the body and see each one of these things harder so all we're really left with are just a few things in nineteen in the 1950s Jane Goodall brought us a little closer to the animal kingdom she found out that chimpanzees iya stools struck every one is remarkable and so from that Victorian perspective perhaps brought us to here as all of these sort of sacred cows have died we've been brought closer and closer till today we are possibly only left with the different ation between us in the animal kingdom with those things that we talk about to identify modernity art prayer it's self adornment perhaps burial of the dead indicating we're special in nature and I have a prediction for you everyone here that's probably a little more than a prediction I wouldn't hold on to all those things either because what we're now seeing as we begin to actually explore Africa the old world other places those sacred cows are probably all going to die and it's gonna be a very interesting moment for us as we seek a definition within our field of what is it to be human when there's nothing left that makes us actually unique but if you are arguing that human uniqueness doesn't exist you mentioned in your talk a couple of things spirituality the ability to ask what does it mean to be a modern human and know what that means wouldn't those things be unique to human beings well they are right now they are at least by the the the sort of superficial definition that we see but we don't know where they begin you've heard that you've heard that Paul is talking back perhaps there are things beginning two million years where does language begin and what would it mean I would pose you what would happen opposed to anyone what would happen if we found another species of non-human animal that practiced those things okay it's the Star Trek question right it's the idea of how do you meet an alien in what would we do because with all these other biological morphological archaeological behaviors falling away have we reached a point where the definition of well we can just recognize humans is not enough so who wants to jump in here Paul you look very interested I always listen to leave it there's a famous old saying in science which goes the question is what is the question and that's a much more profound statement than it sounds and then often we don't once we frame the question correctly it leads us to a theory and finally we say oh yeah get it now so obviously we are of the view that we can define human uniqueness and it all emerges as a consequence of the single trick we have cooperation is the penalty of kinship and so a counter I guess the volley back to leave is do we see other animals that engage in large-scale cooperation independently of kinship I believe the answer is no we can also ask if we're not unique why do animals live in our zoos and we don't live in theirs right I mean I think I think it's a very very specific reasons to believe that uniqueness is not an empty and illusory concept the challenge is understanding what it might actually be if I could go back at the barrage of the person using projectile weapons it's interesting that Paul sort of giving a very loose definition of humans he's carrying it back let's say rather subjectively to some levels of creature where we have as yet not found human morphology by pushing those that humaneness back to nearly 2 million years you're having to grab into morphologies that are near human perhaps with the rise of homo erectus or things like that but they're not at least by a present biological definition that biology exceeds all of modern human variation so you're having to accept now to exceed even that and yet still call it human so it's a Haverhill definition that doesn't stand the test of a biological definition Steven you said earlier that you try not to get involved in definitions of what makes do you find this fascinating words for a living I own to work for a dictionary yeah so yeah I'm this conversation important and relevant or not so much for me not so much for a couple of reasons one of them is that in general they generally don't have definitions they point to things and then your best scientific theory indicates what the boundaries of that class are and that fuzzy borders and perhaps a lack of a clear definition or are they rule rather than the exception and I think that's especially true with the products of evolution evolution is a gradual process there's no point in the lineage from the common ancestor between chimps and modern humans where you can say well that mom was not a human in that trial there's a human we know that its gradual and moreover because evolution isn't a linear process but rather one of a richly branching tree at any given time you can have multiple groups that are related to each other to varying degrees if they get too separated we might for convenience put them into different biological taxonomic categories but then sometimes they can they can interbreed there may have been a whole bunch of species coexist in fact we know that I'm saying may have been we know there were a lot a bunch of coexisting species one of them survived but the other ones were certainly around and if we gave back in a time machine we'd see lots of creatures and which ones you want to call humans and which ones not might be partly chauvinism the ones that are closest to us we'll call humans but it seems to me there isn't a scientific hypothesis or a fact of the matter as to which ones were humans that's a question of how we want to use the word human what's indisputable is that that we are in the whole space of features of organisms we're sitting off in a corner without a whole lot of surviving relatives if you go back in time there must have been a chain linking us to humans but now there were just very very unusual along many dimensions at once and that's probably as close to a definition as we'll get to characterize what those unusual traits are Dean where would you like to enter this well I think that if we want to ask what makes us human that it's interesting to ask what is that people do universally that other animals do not so we can look at humans today and we can identify some things one of which is grammatical language the motherese so I think that we can begin to find things by looking at contemporary people and then it's as Lee said it is problematic because when you go back in time you can't unless we get the time machine we can't be sure you know when these things show up but you can make reasoned inferences so I'm not as pessimistic about whether or not we can define humans or make a step towards it another thing is that with the reorganization of the brain it's true brain size got bigger in it and it reorganized and there's variation like in Hobbit that's a advance looking little a tiny brain so one has to acknowledge that that variation which adds problems to interpreting the fossil record but something that our species does that we don't see in any other animal is with our language you can take a chimp and send it to college and it'll be a little bit of language but they don't ask questions so the human species is a curious one and it expresses its curiosity by asking questions so I would throw that into being human so I think we look for universals to begin to get and get at this complex question brain can I ask actually that's the question both of Deena and we so there have been various claims I think most recently by Fred's four and Christopher Dean that there may be multiple homo species existing contemporaneously perhaps anchored 2.3 million or earlier in other words suggesting the possibility of an adaptive radiation of homo do you guys believe that and can you comment on that you want that first well in recent years the concept of the hominid evolution has become bushier part of the problem is that you have a lot of workers out there hunting for hominids and when they find them they often name it a new species and say AHA this is the one that was on the line leading to homo sapiens forget those other fossils and you can almost bank on that bet on that so the pictures complex and we've just having this week within the last week another example of a new species named and the question comes down to how do you interpret the variation your fossils and you can be a lumper or a splitter so it's not an easy question uh but I'm not an explorer who's actually discovered for guiltily named new species let me let me though say something that might surprise everyone if you think human or our species is hard to define there's absolutely no definition of a genus so it's actually irrelevant on what we're calling those fuzzy transitions between 2 and the reason there's a problem is we haven't defined what it is to define parameters I would go back to it seems to me like some of the suggestions are well let's let's just eliminate everything that isn't a human and whatever is left is good enough for the definition but it's not because we can't get into these answers to these deep questions what is driving all these critical behavioral issues is it babies is it throwing rocks at babies is it speaking badly about babies that you're throwing rocks at we need to box that off so we can understand are these driving or how will we recognize parallelisms homo play z how do we know those have anything to do with the origin of our species or we're just not missing the picture from a bad archaeological and fossil record let me emphasize those it's important not to surrender to a council of too much pessimism the history of science is that fins are pretty fuzzy at the beginning but as you as you start to make progress there's a reciprocal dance reinforcing dance between theory and empirical evidence that starts to bring things into sharp focus I think what we all agree that that will ultimately happen here I think the only potential disagree how close we are to that moment we have some questions coming in from all over the world Ruta from Melbourne asks why did the development of written language cause humans to present the natural order of the species as patriarchal I think that's for you Paul right because the guys who wrote that written language were elite males roman legionnaires Aztec warriors these were individuals who were writing the story they thought was true that is that they were ordained by God to rule All Humans does anyone else have a different perspective on that there were countless there was a lot of bookkeeping with trade which was that the origin well that's the origin of it language but that's not the question why did written language reflect patriarchy that was the questions the accounts let's not get into whether men are better at math I'm good could can I ask a question though within that there are pictographic languages that are written and these perhaps go back into deep time and are perhaps related to storytelling in some ways and how do you know men did that so that's a really profound question what are the things we cave drawings for example might actually a pictographic language I was referring to written language as formalized document generation in that sense we know that that's fairly recent 5500 years or so but yes that's a profound an interesting questions okay Maxine from Toronto asks what would you have to say about Studies on grain size decreasing with domestication and larger brains being linked to aggression by the larger brains lead to human uniqueness your expert on Brees did peak with Neanderthals in terms of size so then they subsided a little bit and they've leveled out to where they are now it's unlikely that they're going to get bigger because of the difficulties to do with childbirth the obstetric dilemma so the ongoing evolution and there will be I think there is it has to do with the reorganization of the brain in terms of the aggression in brain size I'm not quite sure where the questioner is coming from males do in primates including the human primate on average have a little bit bigger brain so I don't know if this was a question about whether or not males are more aggressive than females but the question was larger brains being linked to aggression you accept the premise I would just I mean I sort of reinforce what was alluded to by both Stephan and Paul and and Dean in fact that you know it is probably fair to say fairly dramatically that we are the most peaceful at least mammal that has ever lived in the history of this planet don't mistake I'll see you outside after the that the fact is is that I think it is a mistake to emphasize the sort of application of technology and our ability to slaughter lots of people perhaps with our willingness to do so in society's punishment for those behaviors when we've feminized the male's we reduced our canine size these are all markers effectively of lowering intraspecific violence and particularly among males but across a whole community and then punishing those that step out of that line just to elaborate a little more clearly on that I Stephen said it correctly not only if you put our closest living relative 50% of chimpanzees in an appropriate sized room like this with breeding aged males and females are unrelated that you would have chaos you'd have a bloodbath right and that's true of everything let me emphasize that both Josh Goldstein and Steve Pinker written eloquently about the fact that not only are we the most peaceful of all mammals usually maybe a low bar but that we respected but but in fact we're getting dramatically more peaceful over time I highly recommend both of these remarkable books on that subject steena well now I watched the news in the evening and read the newspapers in the morning and quite often their reports of people who for reasons to do with their beliefs are suicide bombers that kind of thing and so my question is and this is fairly prevalent my question is what happens if some of these weapons that we've created because of our big brains get into the hands of the wrong person so I'm not as convinced that everything's hunky-dory in terms of our being peaceful today I think it's a serious potential problem yeah I'm not I'm not sure that whether that when we emerged as a species we were the most peaceful in terms of the numbers that I'm aware from Richard Wrangham and Michael Wilson rates of lethal violence in pre state people peoples were comparable to those of common chimpanzees of wolves of stags I don't know how many species they surveyed but just the percentage of males that are killed by other males of the same species or kind of in the same ballpark but I think that they have been coming down and because some of our of all capabilities including those for cooperation and for punishing aggressors might have outstrip other parts of human nature namely both the ability and tendency to engage in exploitative violence and the ability in tendency to engage in moralistic violence and a lot of violence is indeed punitive it's morally driven you don't let wrongdoers get away with what you think of as some infraction and that licenses vast amounts of violence which historically although not biologically has been in decline or at least so I argue I'm just thinking the people in the audience maybe one are we really more peaceful than horses or dolphins those are mammal dolphins are dolphins are nasty and horses too at the right time there was a beautiful picture of a couple of them fighting there but again I I would say the one qualification is that animals domestic animals particularly the humans have had enormous influence in selecting human-like qualities in might I say may lower some of that but generally there's only one bull in a field and one more Jake Holman no location listed asks I think Stephen this is so you're here that's why there's no location asks at what point does our accumulation of knowledge hit the barrier on an individual's cognitive abilities are we there now Stephen is that for you what you think I guess well not that the its inherent to our species that knowledge is collectively acquired and transmitted so what an individual can conceive of is not as important as what the collective enterprise of science and scholarship has accumulate and we're certainly not at any natural limit I think when it comes to an individual human mind we are bumping up against truths revealed to us by science that are highly unintuitive it's difficult to grasp the fine points of quantum mechanics of relativity scales very large scales very small perhaps aspects of consciousness and free will that what our best neuroscience tells us is true is very hard for us to swallow intuitively so much the worst of our intuitions the reason that we have science is that we collectively come up with a picture of reality that might transcend what any of us individually could think up on our own let me ask closing question I came in tonight wondering if this conversation would just be interesting - you know people with the human trade of curiosity about what makes us unique if we are unique and where those traits would have come from or if we can put any of this to practical use for ourselves or society I think Paul you're the only one in the panel who addressed kind of understanding our human nature well enough hopefully to avoid destroying ourselves or the planet does anybody else have a practical application for this or is this what you study just because you find it interesting oh no I you know probably everyone in this room has tried to find out who their grandparents were great grandparents were etc and the reason that you do that is often very interesting to sort of soul-search why are you interested in that one of the reasons is even without the knowledge of genetics and other things you know that a part of them lies in you and that you are the way you are because of the way they were physically and perhaps behaviorally which might be more interestingly what we're doing is paleoanthropologist is doing that for the whole species in deep time we are the most destructive people on this planet at the same time we're the most peaceful we'd love to drive things to extinction that aren't on our own species with very little threat of driving our own species unfortunately to extinction and so that's supposed to be funny and and we need to understand the origin of these behaviors we need to understand what drives us and these Sciences collectively are the only way to do it yeah I think the what's been emphasized this evening is that we are a problem-solving species where technological species we're also a punitive species and there are a lot of the world's problems that we can attack with either of these mindsets we can ask ourselves who's to blame let's find them and punish them or from everything from war and peace to economic crises or we can say let's set this up as a problem to solve how can we make the things we don't like less likely without necessarily having to find bad guys and punish them and I think the reduction in violence and the increase in flourishing comes from treating our problems as problems rather than as sins with villains who who ought to be punished okay yeah I think it's great that we have people contemplating these questions and worrying about our future and where we're going to go and we academics can sit here and discuss it but if I think one thing that I would like to see happen I don't know if it well if I like to see people politicians and world leaders become more knowledgeable about these kinds of discussions so that they might apply [Applause] [Music] [Applause] [Music]

Channel: World Science Festival

Views: 180,118

Rating: 4.5552282 out of 5

Keywords: Planet of the Humans, The Leap to the Top, naledi, Lee Berger, Paul Bingham, Dean Falk, Steven Pinker, Brian Lehrer, Darwin, evolution science, communicate through language, anthropology, linguistics, biology, Blanca Li, Cognitive Niche, origins of humans, most peaceful mammals on the planet, New York City, NYC, world science festival, full program, World, Science, Festival, 2015, Big Ideas Series

Id: V3IlnuMG39U

Length: 77min 28sec (4648 seconds)

Published: Thu Aug 27 2015