William Von Hippel - How We Evolved

William Von Hippel is a Professor of Psychology at the University of Queensland and Author of The Social Leap. Today we learn the story of how our ancestors went from being chimps in trees to bipedal apes out on the plains and why we took that dangerous step in our development. We discover why our brains more than trebled in size and how that benefited us, what tools and tactics enabled these early humans to survive in a perilous new environment and what the implications are for our modern day minds dealing with primitive motivations. Further Reading: The Social Leap - http://amzn.eu/d/iFGKgsg - Listen to all episodes online. Search "Modern Wisdom" on any Podcast App or click here: iTunes: https://itunes.apple.com/gb/podcast/modern-wisdom/id1347973549 Spotify: https://open.spotify.com/show/0XrOqvxlqQI6bmdYHuIVnr?si=iUpczE97SJqe1kNdYBipnw Stitcher: https://www.stitcher.com/podcast/modern-wisdom - I want to hear from you!! Get in touch in the comments below or head to... Twitter: https://www.twitter.com/chriswillx Instagram: https://www.instagram.com/chriswillx Email: [email protected]

• 0:06Speaker 1

  Hello, friends. This week I'm sitting down with William Von Hippel, who is a professor of psychology at the University of Queensland in Australia. His work's been covered in the Australian New York Times, The Economist, Harvard Business Review, Time Magazine, and the Sydney Morning Herald, amongst many other publications. And on top of that, William Von Hippel sounds like a baron from medieval times, which is it's the sickest name ever. So I first came across Bill's work when I heard him on Joe Rogan's podcast a couple of weeks ago, and I was absolutely fascinated. Very fortunately, we've managed to find a slot in Bill's book tour, which he's currently undergoing in America, and I managed to sit down with him to go through his new book, The Social Leap, the new evolutionary science of who we are, where we come from and what makes us happy.

• 0:57Speaker 1

  If you have ever wondered about how great apes in trees became bipedal beings out on the plains and then evolved into the humans that you see before you today, this podcast is really for you. There's a beautiful story element and a narrative behind what Bill talks about, plus there's loads of implications for how we operate today. Again, the same as with my podcast I did with Professor Robin Hansen, the elephant in the brain. Why we are the way we are nowadays is a lot due to the environment that we evolved in. But in other news, I have got some messages about why there wasn't a podcast up on audio platforms last week. And if you do not follow me on social media, you may not know why. However, we did another YouTube exclusive, what it's really like starring on Take Me Out.

• 1:45Speaker 1

  Uh after the what it's really like on Love Island podcasts, we decided to double down. If it ain't broke, don't fix it. Sure enough, the podcast has taken off really quickly, and it's been covered by some of the UK press, which is always good news, despite them misquoting me and one of them misspelling my name, but whatever, it's fine. Um But we're back on a schedule. I've got Johnny and Cif coming up very, very soon to do some special edition Christmas podcasts. I've also got the fattest, thickest, longest section of recording that I've ever had to do in the build-up to Christmas. So you may even get to a week over the Christmas holidays, but don't hold me to it. In the meantime, we're going to find out why we are the way we are and where we came from.

• 2:31Speaker 1

  Oh yeah. PS. The first minute and a half might sound slightly different to normal. I was still fighting with Skype at this point, but don't worry, I was victorious. Normal audio services resumed after a couple of minutes.

• 3:00Speaker 1

  Professor William Von Hippel, how are you today? Good. Very happy to be here. Very happy to have you on. It's been a technological catastrophe so far, but it would appear that we've managed to uh tame all of the electronics that we're using to get this call to work, which I'm really, really happy about. So thank you for that. Totally my pleasure. I've got high hopes. Um the social leap. You are currently on your book tour, that's right. That's right. Amazing. So the social leap. What is it?

• 3:31Speaker 0

  So that's the term I use for the kind of solution that our ancestors came to when they left the rainforest and were forced to move to the savannah. And so, you know, here they were, these sort of chimp-like creatures who were really at the top of the food chain when they're in the canopy, but were very vulnerable on the ground. And so how did they solve that problem? Well, I think it took a few million years of sort of skulking around the edge of the savannah, but eventually, and I believe by the time we got to Australopithecus, they had learned to cooperate and band together in their mutual defense. And so I call this the this leap from the trees to the savannah, and then this increasing sociality that are came with that leap, and that in fact, I believe started off our entire evolutionary process that brought us to where we are now.

• 4:17Speaker 0

  That's what I call the social leap.

• 4:19Speaker 1

  Amazing. What was the process of researching the book before we get into it? What was the Sure. Is it a lot of deductive reasoning? Is it uh analysis of

• 4:29Speaker 0

  the B. Well, there's a lot of really fabulous um archaeology and paleoanthropology and other forms of anthropology that people have done to try to make inferences about where we came from, what were the cognitive capabilities of our ancestors and their social lives like, and you know, there's not much to work with when you're looking at fossils that are millions of years old. Uh, but but these people have done a fabulous job of trying to infer cognitive abilities in the deep past, and all I did was really come along and read this literature. Um I've got a wonderful colleague, set of colleagues at UQ who are expert in these areas, and we all we have these uh fortnightly meetings where we hash it out. We've been doing that for about the past dozen years. And I finally got to finally got to the point where I felt like, okay, I I think I've got the story figured out, and it makes sense to me how it fits with our modern psychology.

• 5:20Speaker 0

  I think it's time to try to tell that story.

• 5:23Speaker 1

  Fantastic. So let's start the story then. Where does it begin?

• 5:27Speaker 0

  So it begins six or seven million years ago. We don't know exactly, of course, but basically the story is um as the uh tectonic activity in the Great African Rift Valley increased, you got a lot of upwelling on the east side of the Rift Valley, as um, I gather it's a bit of thinness in the crust or a hotspot or something that's a result of the um two plates tearing apart, or the single plate becoming two plates, you know, starting up at the Red Sea and working its way down to the coast of Mozambique. So the whole right side of that Ethiopia, Kenya, Tanzania, um vast areas of Bi Air, you know, today about a mile up. And what that appears to have done is caused the rainforest to slowly dry out, um, with the end result that our ancestors had very little choice but to move to the savannah because the there was simply wasn't enough forest left for them to make a living.

• 6:19Speaker 1

  Right. Okay. So that move, it must have been very biologically expensive and very vulnerable for a while.

• 6:27Speaker 0

  Absolutely. I mean, I I suspected it was devastating, and that we, you know, if you replayed that a dozen times, I bet you that 11 times out of 12, all you get are a bunch of dead chimp-like animals. But somehow we got lucky. And and you can look at cues of how we got lucky by looking, for example, at um the chimpanzees in Senegal who live on the savannah, and by looking, of course, at Savannah baboons and other primates who've chosen to live on the ground. Um, I suspect that the chimps in um uh in Senegal are a great choice because if you look at what they do, they basically do the kinds of things that I would imagine our ancestors would have done, which is sort of skulk around the margins, try to keep a tree in sight at all times, and make a break for it whenever you know a predator comes along, because leopards, lions, hyenas, all those would now be an enormous threat.

• 7:18Speaker 1

  Yeah.

• 7:18Speaker 0

  Despite the fact that when they were in the trees, they were not a threat at all.

• 7:21Speaker 1

  Yeah, I get that completely. So is there any crossover or chimps moving towards those chimps actually moving towards the development that we had?

• 7:30Speaker 0

  Well, I don't think so. And the they don't they don't they do show well, I shouldn't say that. They're showing some very interesting early signs that look a little bit like what I suspect that we did. So, for example, they tend to share a little bit better than chimps typically do. They um they're the only chimps that we know of that sharpen sticks into spears by biting them and then use those spears to um uh stab and retrieve um monkeys that they eat, these bush babies out of tree hollows. And um, and they even sleep in caves. So there's some very interesting things that they do. But I actually think that the shift that mattered was one that probably took a few million years, and that was um an animal that was now exclusively living in the savannah and had become bipedal. And bipedality in my mind, um I we can talk about where that came from, but in my mind it played a critical role in leading to us because it changed the body of our ancestors from one that was not a very effective body at throwing to one that was now very effective at throwing by virtue of the long longer waist, by virtue of the muscles no longer being so vertically oriented in the chest and shoulders and being more lateral, and um by virtue of greater flexibility in the wrist because they weren't using it their hands as a platform to climb trees as much.

• 8:46Speaker 0

  All of those things would have enabled much more effective throwing.

• 8:50Speaker 1

  Okay, well, why is throwing so important? Well, so throwing is

• 8:55Speaker 0

  uh probably the most important military invention of all time. Not throwing per se. I know that sounds outlandish, but not throwing per se, but rather the capacity to kill at a distance. Right. So no other animal has that capacity, and that capacity is mission critical to enable a larger force of weaker individuals to overcome a smaller force of stronger ones. So if you and I were and our friends were on the savannah and a lion came along and we wanted to attack it. Imagine we're all armed with knives,

• 9:23Speaker 1

  and

• 9:23Speaker 0

  there's enough of us. We could kill the thing, but we know full well that whoever goes in first is gonna be lying different,

• 9:29Speaker 1

  right?

• 9:29Speaker 0

  We'd all

• 9:30Speaker 1

  be going, you I'm after you, Chris. Yeah, no, no, no, no, no, Billy, you can go first. Exactly.

• 9:35Speaker 0

  And so, but once we could throw, now we could attack a lion or defend ourselves from a lion at a safe distance, and especially if there's enough of us, all throwing stones at the same time. Now we're in a position to actually do great damage to the lion without suffering any damage to ourselves.

• 9:51Speaker 1

  Right. Okay. So that that sounds a lot to me. There's a a show on Netflix in the UK called the Evolution of us. Have you seen this or heard of this? I I

• 10:02Speaker 0

  haven't. It sounds very

• 10:03Speaker 1

  interesting,

• 10:04Speaker 0

  though.

• 10:04Speaker 1

  So it sounds an awful lot like the story that you're going through at the moment. And on it, they had got monkeys. They'd attached, attached different um microscopic dots that can be tracked by a computer, and then they tracked their walking gait when they walked on a treadmill. And one of the one of the big differences that they highlighted between those monkeys and us was the size of our glutes. The monkeys essentially don't have any glutes in comparison with us, it's the biggest muscle in our body, right? And that capacity for us to be able to stand up straight and to be able to run long distances, they they highlighted this really big difference. Because when you watch a monkey walk on two legs, it it's pretty unwieldy, isn't it? It it moves, it moves super weird.

• 10:50Speaker 1

  It doesn't look like it was meant to do that. And I guess that's because it's not.

• 10:55Speaker 0

  Yeah, that's right. So chimps and apes, you know, and monkeys in general can't lock their knees. They have no need to be able to do that. And so their whole body isn't shaped properly for walking on two legs. Of course, they can do it, and especially if when you see them in water, they tend to do it. And occasionally they just do it for other reasons. But um by the time we get to Australopithecus, we were bipedal. And so there's those famous footprints, I don't know quite how to pronounce it, Laetoli footprints that uh Mary Leaky, if I remember I'd found. And they, when you computer model those footprints, you can see that the foot strike is of an animal that had locked its knee and therefore its full weight was coming down on its heel, something that a chimpanzee can't do. And so that makes the good reason why our ancestors would have become bipedal.

• 11:42Speaker 0

  It obviously would have taken a while. One of those reasons is probably this notion that you were just discussing, the idea of persistence hunting, that it's it it requires fewer calories to run long distances on two legs at a slower pace to chase down antelope and other animals that will sprint as hard as they can and then soon enough become exhausted and can be killed. So many people have argued that that's part of the reason why we became bipedal. And I suspect it's true. Any change that's that big is highly likely to have multiple causes. I I think that that was um an advantage of bipedality. My personal view is that's not what caused it. What caused it is probably psychological factors. And but the outcome of those of that change was now an animal that's much more effective at throwing. And and of course, the key to throwing is if you imagine one Australopithecus throwing rocks at a lion, well, it's gonna end up in the belly of a slightly bruised and annoyed lion.

• 12:36Speaker 0

  But if you imagine 50 osteopithecenes throwing rocks at lions, now you get a world where you could conceivably drive it away. And so there would have been enormous evolutionary pressure on these ancestors to learn to work together in a way the chimpanzees simply can't do. And that increased sociality and cooperativeness then would have kicked into a gear, all sorts of forces that led to our brain expansion and led to where we are today.

• 13:00Speaker 1

  Okay. So you mentioned psychological factors that you thought that was the reason that we moved to bipedality. What are those?

• 13:09Speaker 0

  So if you look at chimpanzees, they're incapable of planning for unfelt needs. So if if it's hungry now, it can plan to like maybe grab a branch, it'll go over to a tr a shrub, it'll grab a branch, it'll strip the leaves off, and then walk over to the termite mound and dip it in and fish out for uh termites. And so in that sense, it's planning for a felt need. It's hunger and it's desire to eat termites. But once it's finished fishing for termites, it can't imagine that it'll ever be hungry again. And so it literally throws the stick away and and off he goes. And of course, there's lots of experiments that do that in a more controlled fashion where you find that exact effect that it simply isn't capable of considering the fact that it might be hungry again or anything else. Now, if you look at our ancestors like Australopithecens, there's no sign that they either could plan for unfelt needs.

• 13:58Speaker 0

  Now, of course, that's super hard to know, right? They've been gone for millions of years. But the one thing the chimpanzees couldn't do it. And then when we get after Australopithecus, we get to Homo habilis and the tools that they made, these old one tools, which are very slightly sharpened stones. And some people argue that Australopithecines were sharpening stones as well. There's some controversial evidence about that. But either way, there's the tools that either Australopithecus made or that homohabilus made have never been found at any great distances from where they're acquired and made. And what that suggests is an animal that's making a tool for its immediate use and then literally leaving it behind. Now, it's possible, of course, that it's easier to make a new one than it is to slap it with you. We don't know.

• 14:44Speaker 0

  But by the time we get to Homo rectus, they're making a much nicer tool. It's uh bifacial, it's really uh the shuling tools are really quite lovely, and they're carrying them to at great distances. So we know, at least by the time we get to the next species down the chain from Homo habilis, we know that we've got an animal that can envision unfelt needs. You know, I've used this tool now, I'm gonna want it again tomorrow. So then the question is, how does that tie to bipedality?

• 15:10Speaker 1

  Yeah.

• 15:11Speaker 0

  Well, if you're a um an Austral, if you're a chimp-like creature in the savannah, and you're setting out across the grass for food or for whatever purpose, you and and you cannot envision unfelt needs. Some people said, well, maybe they develop bipedality in order to carry a weapon or to carry food. Well, that's not super plausible in the sense that they're not trying to prepare for the future. If if an Australopithecus was hungry, it would eat the food.

• 15:37Speaker 1

  If it's

• 15:38Speaker 0

  not hungry, it would leave it behind because it won't envision being hungry again. So then you have to ask yourself, well, what might an Australopithecus feel? What would be its felt need every time it set out across the savannah? And I think it's super clear that you imagine yourself this, you know, three and a half foot tall guy um setting out across the open grass, I think you're gonna feel fear because any, you know, you're just you're just available for any major predator, any large cat or dog that's out there.

• 16:05Speaker 1

  Yeah.

• 16:05Speaker 0

  And so if your felt need every time you set out across the savannah was fear, then what you would probably want with you is some sort of weapon. So if chimpanzees today who live on the savannah can chew a stick and make a sharp point, I'm sure our Australopithecus ancestor could do the same thing. They had slightly larger brains than a chim. And so my guess is that they're fashioning a crude spear or club or even stone, and they want to carry it with them every time they set out across the savannah. Now they may need to make a new one every morning, because when they get home, they don't think they'll ever need it again.

• 16:37Speaker 1

  Yeah.

• 16:37Speaker 0

  But every time they set out, they're going to look for something like that. And that, of course, will be a psychological pressure toward bipedality, because it's much easier to carry a spear or some other sort of weapon if you can walk on two legs. Aaron Powell

• 16:49Speaker 1

  I get that. I get that. So why why go out on the plains

• 16:53Speaker 0

  at all? Well, because the trees are disappearing. You're in the no-choice condition. You've got like five trees that you're sitting in, but there's nothing to eat there. Yeah. And so if you want to find food, if you want to f um, you know, get to another stand of trees where there might be other safety and other things to eat, you've got to move along.

• 17:08Speaker 1

  Right. Totally. You mentioned uh brain size, differences in brain size there, and also obviously there'll be big differences in physiology. What are the differences between the closest relative that we've got and the Australopithecus in terms of brain size and then in terms of structure?

• 17:25Speaker 0

  So the Australopithecus has about a 450 gram brain, and the chimpanzees are about 380. So you've got about three million years on the savannah has given you about 70 grams of brain power.

• 17:36Speaker 1

  Not a whole lot. Big investment, but not a lot of returns. Right,

• 17:39Speaker 0

  right. Well, I think that that's I think there's good reason for that. And I think that good reason is is that brains are super expensive. You know, we just think of them as an unmitigated good because they can do so much for us. But until we live in a world where you you have a purpose for your brain, you're paying a big price in calories. Our brain uses 20% of our metabolic energy at all time. So that's a big cost. And what what return are you getting on that investment? Well, as a chimpanzee, what are you going to do with a little more brain? Um it's not it's not clear when you don't cooperate with each other, when you don't work together well. It's not entirely clear that you're going to gain something to offset the losses. Part of the reason for that, of course, is that they don't have control of fire, and so they can't release nearly as many nutrients from their food as we can. So Richard Rangham talks about that in his wonderful book catching fire, how basically in order to develop the big brain that we have that's supported by such a small gut, you need to be eating a lot of meat and you need to be really releasing as many calories from it as possible, as many nutrients as possible, which is achieved um by cooking.

• 18:40Speaker 0

  Because raw food simply is I mean, you can just you can tell just by the sense of smell. If you if you sniff a steak that's cooking up nicely, it smells beautiful, if assuming you like the taste of meat. If you sniff a raw steak, it just doesn't smell beautiful at all.

• 18:54Speaker 1

  No.

• 18:54Speaker 0

  And and the same holds for potato. A raw potato is inedible. A cooked potato smells and tastes delicious. And so that's our that's our evolved understanding of what's nutritious for us and what's not. Aaron Powell

• 19:06Speaker 1

  Yeah. I really wanted to touch upon this. The way that I think uh a lot of modern humans, if you don't look into evolutionary biology, sweet things taste sweet because they're sweet is kind of like the sentence, right? But that's not the case.

• 19:23Speaker 0

  Well, no, no, because our ancestors were constantly in search of salt, sugar, and fat. Those are the three things that allow us to survive and that are in short supply on the savannah in the jungle, anywhere else. And so, but we lived in a world where there was never enough of those things. And so we didn't evolve a psychology that says, well, I only want a little bit. We evolved the psychology, I want to get as much of it as I can.

• 19:45Speaker 1

  And

• 19:45Speaker 0

  so it's super hard to stop eating that stuff because our ancestors never worried about eating too much of it.

• 19:52Speaker 1

  So the McDonald's hacking of sweet food and salty food and all this sort of stuff, the binging when it When you're binging away on some fast food, it's actually a primitive brain that's kicking in saying this is good for you, you should have more of this because there's not going to be much around.

• 20:09Speaker 0

  Right. It's it is that. But I would actually caveat that ever so slightly by saying that we have evolved to get full when we eat a lot of meat. Because protein is the one signal that we it's it's the one food source that we the macronutrient that we really search out because we um protein, you know, our bodies are built to protein, and we need uh to get enough protein in our diet in order to survive. And so humans and crickets and all the other animals that have been tested basically use protein as a guide to indicate when they're full. And this is really beginning with wonderful research by Steve Simpson, who's a biologist uh who spent much of his career at Oxford and is now at Sydney University. And Simpson has shown he's got a wonderful book, The Nature Nutrition. He's shown very clearly that if you vary the protein levels in food, animals will weigh overeat carbohydrates in order to get enough protein, but they weigh they won't weigh over eat proteins in order to get enough carbs.

• 21:03Speaker 0

  Protein seems to be the limiting factor. And I do believe that it the way it works is that it makes you feel full. And so when you eat a you know, a hamburger at McDonald's or a steak or something like that, you go, oh, I feel so full. Whereas if you sit down with a box of cereal, I mean I could literally eat a box of cereal while I'm watching television and not even feel it, not even and I'll have consumed way more calories than I would get out of uh Big Mac or a steak or something like that.

• 21:30Speaker 1

  Why is there this upper ceiling on the protein intake, do you think?

• 21:34Speaker 0

  Well, so think about our ancestors. They would have uh so today they get lucky and they kill a giraffe. Well, they're gonna stuff as much giraffe down their pile hole as they can, but they're gonna get to a point where all right, I can't eat any more of this. I'm feeling super full. They would have only very rarely been in a situation where there was so much carbohydrate that A tasted very good, and B, they wanted to eat. And so there's just gonna be little evolutionary pressure on them to detect that they're full from carbs, but a great deal of evolutionary pressure to be able to say, all right, well, now I'm sated, I've had enough protein.

• 22:05Speaker 1

  Amazing.

• 22:06Speaker 0

  And interesting, interestingly, the data also suggests that part of that is driven by lack of variety. And so if you serve um, there's some interesting work with amnesics, people who have such dense amnesia they won't even remember five minutes ago. And they'll interestingly, they'll eat a second lunch. If you serve them lunch and then leave and come back and say lunchtime, they'll eat it again.

• 22:26Speaker 1

  And you think such a mean it's such a mean experiment if someone's trying to lose weight.

• 22:31Speaker 0

  It is, it is a mean experiment. But it's interesting because the um what's happening there is that they part of our sense of being full is actually our knowledge that we ate. And because they don't have that knowledge, they don't have that sense of as strong of a sense of being full. And but what's interesting is that if you give them less variety, like you say, well, here's the one food that you'll leave for lunch, these sandwiches, they don't want those sandwiches anymore. Again, suggesting that we've evolved to say, all right, I've had enough giraffe, I'm not gaining anything from this, I don't feel like eating it anymore. Aaron Powell

• 23:01Speaker 1

  I get that. There's uh competitive eaters that are in uh ice cream competitions, they offset the ice cream with French fries. Yeah,

• 23:10Speaker 0

  you'd want to do something to allow yourself to keep going. Although I personally can't imagine doing that, but but it makes good evolutionary sense.

• 23:16Speaker 1

  Fine. If if the evolutionary psychologists and biologists say that it's okay, then the the competitive eaters, the competitive eaters have got it right. So Australopicus Australopithecus is now on the edge of the plains, maybe developed some tools and uh this level of cohesion within the group, and they can, I guess, really rudimentary tactics to take down prey. What where do we move from there? What do we roll forwards onto from there?

• 23:43Speaker 0

  Great question. So now here we are with this animal that's barely gained any brain power, but is bipedal and has a capacity to throw and probably has the psychological understanding that we need to work together and a tendency, uh, you know, a preference to cooperate. Because of course, evolution works by what you want to do more so than by knowledge. Gee, I ought to do this, and that knowledge would have been hard for such an animal anyway. So you now have got a more cooperative animal that uh is sort of working together on the savannah, and that actually opens up all sorts of potential benefits to get smarter. Because once we're working together, well, we could have we can imagine division of labor. Now we can be a much more effective squad. If you go left, I go right, and someone else attacks down the middle, we could bring down this animal and we could have it for dinner.

• 24:32Speaker 0

  And so all sorts of emergent properties come from groups that can envision what each other are thinking, they can find a way to work together, they can um plan for the future that can do all these sorts of things. So whereas in the past, getting smarter would have been very little use. Now getting smarter is of great benefit. So there's some really interesting work that came out recently on uh notch 2NL gene, which is a uh gene for brain expansion. And what the what the data it's new data, but what they suggest is that this gene likely appeared in our line maybe 12 million years ago, and the way it did is that it accidentally duplicated itself, but then this new version was turned off, so to speak. Now, evolution often works this way because if you've duplicated a gene unintentionally, you know, in some in the in the process of meiosis or wherever, if there's an actual accidental duplicate copy, now you can do things with that duplicate without disrupting the function that the original did, because it's an extra, so you can just play around with it, so to speak.

• 25:31Speaker 0

  And so this extra um gene seems to have emerged 12 million years ago or so in our line. And about three million years ago, around the time of Australopithecus, it seems to have duplicated itself again and turned back on. Now, my guess is that it turned back on many times randomly between 12 million years ago and three million years ago. But whoever got that extra gene turned back on didn't gain much from it. The cost of the of the extra brain wasn't outweighed by the benefits. But now you get to these social animals, these australopithicines who are working together, and now the benefits of being smarter can outweigh the cost, because we can gain emergent properties from our group if we can work together better. And so you see rapid brain expansion. So remember, the first three million years gained us maybe 70 grams of brain.

• 26:17Speaker 0

  Now you go from Australopithecus to Homo rectus, you're moving about one million years, and you go from about um 450 to about 960 grams.

• 26:25Speaker 1

  So

• 26:25Speaker 0

  more than doubling of brain size. Now, admittedly, homo erectus is bigger, so it's it's got it's more of a relative issue, but it's still a big change. And then you go from Homo rectus to us, and you've we're now at about 1350. So they've essentially added an entire chimp brain onto Homo erectus in the last million and a half years or so. So massive brain expansion that accompanied the greater the sociality that we gained on the savannah and that enabled us to suddenly become much more effective than we have been before. Aaron Powell

• 26:54Speaker 1

  So is brain size equal to power. Is that the way that it works? Aaron Powell

• 26:57Speaker 0

  Yeah, basically. I mean, the you know, the it's complicated, of course, because elephants have ginormous brains, and to the best of our knowledge, they haven't built great cities or done any of those things. Of course, they don't have hands either, but they do have a fabulous chunk.

• 27:10Speaker 1

  Yeah.

• 27:10Speaker 0

  Um but so it's it's it's an issue, it's uh it's an issue we don't fully understand, but there's no question that the larger brain gives you much more computing power.

• 27:19Speaker 1

  Right. And then you've said, as you've mentioned, a really clever giraffe or a really clever zebra has an upper limit on what the use is, and it's actually a very expensive cost to have that brain and to have to consume all of those extra calories, but you you are given more capacity to utilize that brain when you are able to work together in a group. And you said homo erectus two million years ago, is that right?

• 27:43Speaker 0

  Yeah, a little less. Okay.

• 27:45Speaker 1

  Um and then where did they go from there? How how do we think that they move forward?

• 27:50Speaker 0

  Well, so Homo erectus, we can see signs that they actually can plan for the future. So remember I talked about how they carry their tools around. We also see some really interesting evidence that they work together really well uh with division of labor. So, for example, in making those tools, there's uh a site in India that's 1.2 million years ago that Carrie Shipton has written about, and he talks about how as you look at the site, you can see that the original pieces of rock that they want to fashion into a tool are knocked loose in one location, and then maybe 10 meters over to the right, they're originally worked on for a little bit to get them into the right basic form, and then maybe 10 more meters over, they're now be doing the final sharpening. Well, if one if one homo erectus is making the tool, why would it break it loose here, walk 10 meters, work on a little bit more, systematically walk another 10 meters and work on it more?

• 28:39Speaker 0

  It probably wouldn't break it loose and sit down. But if but if people are working together, if the homorectus knocks it loose, hands it to his mate who's better at the at the second stage, and he hands it to a friend who's better at that final stage. Well, it would make sense that it's systematically being done at certain spatial locations around the site. So it's pretty good evidence for division of labor. Aaron Powell

• 29:01Speaker 1

  It's a primitive primitive Henry Ford.

• 29:03Speaker 0

  Yeah, that's exactly right. It's like a little factory, right? And then we've we see evidence that so for example, um, up by the Sea of Galilee, there's a wonderful, it's just an anecdote, but it's an interesting one, where um an elephant has has either been killed or scavenged, and the homo rectus who are working there, we see a bunch of hand axes, there are Schule and tools lying around, and we see the head has been broken loose from the um neck and turned over. Now, brains are a wonderful source of fat because the myelin sheath around the neurons. You know, that's so brains are very, very high in fat and cholesterol. But remember, that's what everybody's seeking all the time. And of course, it'd be a lot easier to get into a mammoth's brains through the base of its skull than trying to break the skull through the top.

• 29:46Speaker 1

  Yeah.

• 29:47Speaker 0

  Because they're such massive items. Well, you could imagine a thousand chimpanzees crawling all over a mammoth's skull. It's they're never gonna effectively turn it over because they can't work together. But Homo erectus, you know, everybody heave on three kind of thing. You could imagine that's working together effectively to achieve something that they couldn't do individually. And so examples like these suggest that by the time we're at Homo erectus, we're now super effective. We're using our brain power to accomplish things that we could never accomplish individually, because we can work together as a group, we can divide up tasks, and we can even plan for these future activities like a hunt. You know, you guys come over here, we'll we'll try to get the horses to run down this this way here and we'll dig a trap and we'll capture and kill them. And there's evidence that they were eating horses and elephants, even massive elephants, much bigger than today's throughout Europe.

• 30:37Speaker 0

  Aaron Powell

• 30:38Speaker 1

  So megafon or elephants were being felled by humans who had a brain that was two-thirds the size of ours, but they were so much they were so much more capable of working together that's

• 30:48Speaker 0

  that's right. We don't know for sure that they're bringing them down, right? The all we can see is maybe they were scavenging them. But I think the data suggests that they were hunting them. The if you look at at the marks of the tools on the bones, you can see lots of marks where if they were scavenging, like the up high on the leg near the torso, when when animals uh hunt other animals, they always eat that region first. And yet we see lots of marks on the bones up in the upper thigh bone where where you wouldn't be working with your stone tools if you were scavenging someone else's kill because there'd be left

• 31:22Speaker 1

  there to eat.

• 31:22Speaker 0

  Yeah. So I I think the data suggests pretty strongly, I know this controversial, so not everybody would agree, but I think they suggest pretty strongly that Homo erectus is now moving back to the top of the food chain, and they're doing that via their capacity to cooperate and work together. Aaron Powell

• 31:37Speaker 1

  Fascinating. That's so interesting. What are the what are the tribe sizes that we think at this sort of stage? Oh, that's

• 31:45Speaker 0

  a great question. I don't know. Um they're probably much smaller than what we see today. You know, there's a lot of argument about what's the optimal tribe size in humans even today. And people have given numbers like 150, and and it is the case that humans are quite capable of processing the interrelationships of 150 other humans. Yeah, and and Robin Dunbar has lots of nice evidence showing that. But in actuality, when you look at hunter-gatherer groups, they very rarely are are in anywhere near that size. The preferred size is much closer to 20 or 30, because when you get groups too large, everybody starts to bicker. You know, we've got a world with all sorts of laws and rules and and all sorts of expectations that are formally laid down that that prevent that kind of arguing and bickering, and we're less interdependent. So, you know, if I don't get along with my neighbor, it's not ideal, but I don't have to interact with them all the time.

• 32:35Speaker 0

  Whereas if we're hunter-gatherers and we're actually working together every day on the hunt, I don't want to be with someone I don't get along with. And so groups tend to splinter and break off into smaller groups when that happens.

• 32:48Speaker 1

  You only need one bad apple, I suppose, don't you? Exactly.

• 32:52Speaker 0

  Well, you know, they have good ways of getting rid of one bad apple, right? Because there's no laws against it. Yeah. And so, you know, bad apples don't wake up one morning, or they when they do wake up, everyone's gone. But you know, if if they're a bad enough apple, right? But um but but it is the case that uh homo erectus probably had the exact same issues, and so they're probably traveling around in small um groups that are a combination of family and close friends, and they're probably doing, you know, chimps and humans both are what they call these sort of fission fusion groups where larger groups come together and then they break off and go their separate ways and they re-come together, so long as they're members of the same overarching group. And so I don't know what homo erectus' uh language capabilities were if they had any.

• 33:35Speaker 1

  It

• 33:35Speaker 0

  may have been all gestural, it may have been spoken, we don't we don't yet know. But um there would have been, even if it's gestural, there'll be meanings in some places that aren't quite the same as others. And so there's probably in-groups and outgroups among homo rectus, just like there are in chimpanzees and just like there are in humans. Aaron Powell

• 33:52Speaker 1

  That's fascinating that there would be uh essentially different languages and dialects of these gestural uh communication tools. You could potentially have someone from another tribe that's really really far away that comes in and you essentially can't communicate. I know that sounds stupid considering we're next to

• 34:09Speaker 0

  I'm next

• 34:10Speaker 1

  to France and I can't speak to a French person.

• 34:13Speaker 0

  Right. But it could be very similar. I mean, there's gonna be some basic gestures that everyone understands, but you know, it's always the case that when you travel in a foreign country, people say, don't use that gesture. That's a rude one here, even though it's a positive one where you're from.

• 34:25Speaker 1

  Yeah.

• 34:25Speaker 0

  And I see no reason why that hasn't always been the case. Aaron Powell

• 34:28Speaker 1

  That's fascinating. Um I recently did a podcast with Professor Robin Hanson who wrote The Elephant in the Brain.

• 34:34Speaker 0

  Yeah, it was a great podcast. I enjoyed that.

• 34:36Speaker 1

  Thank you. Well, yeah, it was um uh I found that so fascinating. What I what I really loved, I wanted to dip in there if any of the listeners haven't heard that he had uh an evolutionary justification for gossip, and you mentioned about the one bad apple that gets left every evening. And I I found it completely fascinating that he spoke about the that bad apple that has the social norms of the group and the fair play gets uh it's enforced via the fear that the gossip is going to oust you as being the bad apple. So you want to adhere to what the rules and the norms are, because if you don't, you know everyone's gonna find out about it. I thought I thought it was so interesting to hear that there was a an evolutionary justification for the water cooler.

• 35:22Speaker 0

  Sure. And and you know, if you think about it, it makes perfect sense because we all gossip. We kind of look down on it when other people do it, but we are so happy to engage in it ourselves. Oh, really? Did you hear about so-and-so? And why is it so universally beloved to do it?

• 35:37Speaker 1

  Yeah.

• 35:37Speaker 0

  Because it it because it plays such an important role. It's a way of managing reputations. And so if if I live in a very small group where everybody is in everybody's business and I start misbehaving, well, the group can bring me in line via gossip. And and importantly, they can do it in a way that's very safe. So imagine that I'm the big tough guy in our group, and you and someone else are worried about me and the way I'm throwing my weight around. You know, you can bring it up in a very offhand way, you know, sort of along the lines of, where do you think of Bill? Or not that would be too direct. You'd say, oh boy, oh boy, did you hear what Bill did yesterday? And if the other person then responds with, I must have been a wonderful thing. He's a great guy, you know, you shut your mouth.

• 36:15Speaker 1

  But

• 36:15Speaker 0

  if he says, oh, what was Bill up to, you'd say, well, not totally sure what he meant, but he did this. And then you can see if the other person ratchets it up and says, Oh, what a jerk. Or if he says, Oh, I've never liked it.

• 36:25Speaker 1

  Yeah. And

• 36:25Speaker 0

  so Steve Pinker has this wonderful um talk where he he talks about our indirect uses of language, where, for example, when a um police officer stops you and you want to bribe him, you don't say, hey, can I bribe you? You say, you know, is there any way we could solve this here and now? And you hope you'll say, well, if you give me the 50 bucks, I'll take care of it for you, and you give them the 50 and drive off. But of course, if he says no, you have to pay the ticket, you go, okay, sorry, I thought maybe that we could deal with it here. Now you can that kind of indirect language could be used very easily in gossip if you're unsure about the feelings of the person you're talking to and unsure whether they're going to join your coalition. And so gossip is super important for managing reputations, and it's much safer way of doing so than if you couldn't communicate with the kind of complexity that we're capable of of. Aaron

• 37:09Speaker 1

  Powell There's only two forms, broadly two real forms of communication, isn't there? There's uh words or I guess written communication or body language, and there's violence. That's it. That's right.

• 37:20Speaker 0

  That's right. And of course, if one

• 37:21Speaker 1

  fails, you've got to do the other.

• 37:23Speaker 0

  Yeah. We've got this amazing communication system that the other animals just don't have. And so, you know, we know that all animals can communicate. But if you look at, for example, when chimps try to communicate what's going wrong or what's going on right, they're very limited in what they're able to get across to each other. And there's interesting cases of female chimps trying to communicate um the danger they're in to their male friends or partners, and they just look not like, what are you talking about?

• 37:47Speaker 1

  Whereas human

• 37:47Speaker 0

  beings, you know, our one of the most amazing things about being human is the cumulative nature of our knowledge. And so because we can talk to each other, I can tell you about what happened when that lion nearly ate me out by the water hole, and now you know how to handle it without ever going there yourself.

• 38:03Speaker 1

  Yeah. And

• 38:03Speaker 0

  that and every generation we can build on the knowledge of the past, which enables, you know, we don't have to reinvent the wheel. And you know, children can learn what only geniuses knew just a few generations ago, because it becomes part of our lore, part of our way of doing things. Aaron

• 38:17Speaker 1

  Powell Totally right. I guess that combined with the uh ability to anticipate felt needs is a super super powerful unfelt needs, yeah, sorry, is a um a super powerful combination.

• 38:29Speaker 0

  That's absolutely right. And so our extraordinary communicative abilities facilitate our groups and their capacity to work together. Our capacity we call theory of mind, which is our understanding that the contents of your mind are not equivalent to the contents of my own. So chimpanzees can't do that. They're not they're partially aware, but not fully aware of the fact that what you know is different from what I know. Because it requires this ability to put myself in your shoes, that kind of perspective taking, which is actually very difficult. Humans don't even get it until they're about four years old. But once you get that, now not only can you work together more effectively, because I know what you know, but you can communicate much more effectively as well. If you look at the language of small children, even when they have the words, sometimes they're very hard to follow because they don't know what you know and don't know, and they start a story in the middle.

• 39:16Speaker 0

  But once you know, once you've got theory of mind, once I know what you know and don't know as a function of what you saw and what you heard and all the rest, I can much more effectively communicate with you. I can we can divide up our tasks much more effectively, and I can also teach you much better because I know what you know and what you don't know, so I know where to start when I'm trying to teach you that which our group does, you know, to kill the elephant or whatever it is. Aaron Powell

• 39:41Speaker 1

  That must also tie into lying, then I'm gonna guess and deceit that um theory of mind. Can you explain how that works together?

• 39:49Speaker 0

  Yeah, so absolutely. So if so other animals are deceptive, you know, all across the animal kingdom and even the plant kingdom and uh animals and plants deceive each other by trying to look like poisonous ones when they're not. By trying to disguise themselves, et cetera. But when I say trying, I don't mean intentionally. I just mean that's what they evolved to do. Humans are the only ones who can lie in the sense of intentionally planting falsehoods in someone else's mind. And so you can imagine that when you got theory of mind, you're the first organism to get it. Nobody else has it. You suddenly realize, well, gee, this is what everybody else knows, and here's what I know. I can benefit myself if I try to plant some falsehoods in your mind that make me look better than I really am. And you know, when no one else knows that, the and no one else has that capacity, it would give you an enormous advantage.

• 40:35Speaker 0

  So of course, everybody else evolves that capacity because it's so effective. And now what we see is children start to lie as soon as they get to the point where they have proper theory of mind. Now they'll tell some very simple lies prior, like you say, did you do this? And they know there's trouble, they'll go, no. But that's just that's a very simple kind of lie that doesn't really require me to know the contents of your mind. It's just me trying to get out of the

• 40:59Speaker 1

  way. More reactionary, isn't it?

• 41:00Speaker 0

  Yeah, exactly. And and and famously um Coco the Gorilla, who um Penny worked with with via sign language, famously told her once when she came into their trailer or whatever, wherever he was living, and he had torn Coco, I guess she had torn the um sink right off the wall and and then claimed the kitten did it.

• 41:21Speaker 1

  And so

• 41:22Speaker 0

  um and so it's a great example of you know, very simple lie. No, I didn't do that, you know, and then see you see a cat, he did it, which is but wildly implausible, right?

• 41:29Speaker 1

  Yeah.

• 41:30Speaker 0

  And so the little kids can do that. But once you get theory of mind, now you can start to plant some very impressive lies. And so the um, you know, the small children, there's some wonderful experiments where they'll teach them theory of mind, and then the kids start to lie if it if it benefits them to their advantage. And so until you get there, you can't effectively lie because you don't realize that what I know is different from what you know. So why would you try to plant something in my mind if you assume that our minds are completely identical?

• 42:01Speaker 1

  Yeah, lying's a very complicated when you when you break it down. The fact that we do it so naturally on a daily basis is uh is more a byproduct of the way that we operate as opposed to the fact that it's simple. It's an incredibly incredibly complicated task to achieve. So we're homo erectus. We've moved onto the planes where maybe you think tribes 20 to 30, something like that with some primitive. Total guess. Primitive, I think so. Primitive communication tools, where are we going from there? What's next?

• 42:30Speaker 0

  Yeah, so now the the question is um what happens now, and then how does it lead to where we are today? And one of the important things that would have happened with Homo erectus is now they've moved to the back to the top of the food chain. And so no longer is it the case that saber-tooth tigers or lions or even mammoths are important predators of theirs anymore, because as it as a group, they're so effective that although occasionally individuals will be killed by these um large animals, they're not really a threat to the group writ large. But there is an important threat to the group writ large, and that is other groups of Homo erectus. And so once you've got division of labor and all these capacities, really the only threat to you is other groups who have the same capacity and who might be competing for the same resources. And so what that suggests is that we would evolve in a psychology where we cooperate really well with each other, right?

• 43:20Speaker 0

  Because that's what enabled us to start defending ourselves in the savannah, but we would not extend that cooperative nature to other groups. And so I suspect we certainly know this holds for Homo sapiens, and I suspect it goes back to Homo erectus, that they've now evolved the tendency to be very cooperative within the group, but a group from the outside may or may not be friendly. It may or may not be on their side or against them, and so they withhold judgment and they don't necessarily cooperate with them, certainly not automatically.

• 43:48Speaker 1

  It's a potential existential threat, right?

• 43:51Speaker 0

  That's right. And so that would have led to tribalism, ethnocentrism, and all the kind of genocidal tendencies that we see in people today. I mean the important thing to remember is that the savannah made us cooperative and friendly to each other. But it did that in order to make us more effective killers. So it's not a lovely friendly thing without a negative side, at least from a moral standpoint. What it is is by becoming cooperative and kind to each other, our group works better and can more effectively kill other animals and potentially other members of our own species as well. Aaron Powell

• 44:23Speaker 1

  That's so fascinating that the the basis for tribalism. You know, everyone everyone talks about tribalism and this bipartisan politics and this group versus that group, and it you know, but to to actually find a justification for why we are the way we are. Um that's that you know, it makes so much sense. You wouldn't watch it. What about the the tribe from the other valley? What if they're what if they're ill? What if they carry some some disease or some pathogen or what if they, you know, I guess that's yeah, there's so many reasons as to why we would be wary.

• 44:58Speaker 0

  Right, exactly right. And in fact, you the pathogen example is a great one. That's separate from our possibility of competing over resources and wanting to kill each other. That's where we're accidentally killing each other. And as you get closer to the equator, there are more pathogens, and tribes tend to stay apart more for that very reason. Because, you know, if you and I live in Sweden and I've never you live a thousand miles, a hundred miles away, chances are you and I have been exposed to the same very few pathogens that can survive in that environment. But if you and I live near the equator, well, even if you're only a quarter mile away, you may well have encountered pathogens and have a resistance to them that I've never seen. And so if you and I mingle, you could make me sick and kill me without ever meaning to do so. And as a consequence, I'm gonna evolve a tendency to stay away from you. And of course, that's exactly what we see.

• 45:44Speaker 0

  Aaron Powell

• 45:45Speaker 1

  That's so fascinating. So what um what areas are we talking about that are mostly occupied by Homo erectus at this time. I think you said 1.2 million, one million years ago, something like that. Where where are we on the planet at the moment?

• 45:58Speaker 0

  Okay, so probably by 1.7 million years ago, Homo erectus have both stayed in Africa and left. And so you see um homo erectus moving out of you know through Arabia into Asia and into Europe, and they've basically occupied, beginning around then and then extending until Neanderthals, who are their offspring. They've occupied um the lower half of Asia and they've occupied almost all of Europe, and of course they also have uh colonized all of Africa. And so those Homo erectus who stayed in Africa are the are the ancestors of Homo sapiens. Those Homo erectus who moved out of Africa are the eventual ancestors of Neanderthals. And so when Homo sapiens leaves Africa, we encounter Neanderthals, and as we now know, um we interbred with them a few times, and so uh we carry a fair few neand Neanderthal genes, as well as some of the genes of other offshoots of Homo erectus who had left Africa and lived in um Asia at least.

• 46:54Speaker 0

  Aaron Powell

• 46:55Speaker 1

  It's like two to five percent, right, of our genes. That's right. That's right. And it's actually higher, it's higher in white populations, I think. Is that right as well?

• 47:04Speaker 0

  Right. Well, there's no evidence that um Africans interbred with um Neanderthals because of course Neanderthals didn't live there.

• 47:11Speaker 1

  Yes.

• 47:11Speaker 0

  And so everyone who left, you know, we're Caucasians and Asians, the uh every non-African in today's world is a small subset of the group that left Africa beginning maybe 80, 85,000 years ago. And so those people appear to have left, and some took a right turn and and worked their way toward East Asia, some took a left turn and worked their way toward Europe, and all of those people seem to have interbred with the Neanderthals. Some of them also seem to have interbred with other subpopulations that came from Homo erectus like the Denisovans from that cave in um Siberia. We know that some humans um have some of their genes. And so, but we don't we haven't tested so many Africans yet to say with any confidence that they don't have Neanderthal genes, but so far there doesn't seem to be any, and of course it would make perfect sense that they don't because they didn't leave Africa.

• 48:04Speaker 0

  Aaron Powell

• 48:05Speaker 1

  Well, the Neanderthals as well would be very unsuited to being in that environment, right? That's right. That's

• 48:10Speaker 0

  right. And given that we wiped them out or killed them via disease or whatever, when we encountered them, one can imagine that those who did work their way toward Africa didn't meet a friendly reception and that didn't work out very well if it ever happened.

• 48:22Speaker 1

  Aaron Powell Absolutely. In the uh the Netflix series that I was discussing earlier on, I found it really fascinating where they explained why we have different colored skin. They were talking about the melanin that protects from the sun and that when you're closer to the equator, that's more important, but as you get further north, that actually doesn't keep you as warm. And uh it was it seemed so so bizarre that I'd never thought about it, but the distribution of body shapes and of um physiological makeup, you know, the Inuit um tribes and the people that are in the north, they tend to be smaller with high levels of fat, and then you've got you know, the best runners from the world all come from Kenya. Like why you know

• 49:04Speaker 0

  this

• 49:04Speaker 1

  isn't this isn't a surprise, right?

• 49:06Speaker 0

  Right. I mean, local ethnic groups adapt to the place they live. It's it's not a very sensible thing to think about race, which is such a broad category that it covers too many ethnic groups. But if you think about different ethnicities, they make perfect sense that they have to find a way to make a living where they are. So my younger brother is a biologist who works up in the Bering Sea with a bunch of Inuit groups trying to help them um study the uh the consequences of these um perchlorates and stuff that have been left by the military that might be cancer causing. And so he was up there one summer in way up in northern Alaska off the Barian Sea, and the water is like, you know, one or two degrees Celsius in the ocean, and the local kids are running in and playing. Oh

• 49:48Speaker 1

  my gosh. And you know,

• 49:49Speaker 0

  if you if you went up to your ankles, you'd nearly have a cardiac arrest because it it's just so cold, it's unbelievable. But they've got this sort of thin layer of subcutaneous fat that protects them in a way. That people who aren't inuit just don't have.

• 50:02Speaker 1

  Yeah, that's so interesting. So when we're talking about these tribes and stuff, I really wanted to get on to discussing sexual relationships and how partners and child rearing worked throughout the timeline that we're talking here. Would you be able to explain some uh theories behind that to us? Aaron Powell

• 50:21Speaker 0

  Sure. So the child rearing and partnering is complicated because human beings are so behaviorally flexible that we've got lots of ways that we do it. But there are some simple, not simple. There are some underlying rules that apply to all of us. And basically the underlying rules stem from sexual selection. The notion that, you know, the Darwin proposed that you both have to find a way to survive, which is kind of what we think of with natural selection, you know, uh not dying when you get attacked by a predator finding enough to eat, but you also have to find a way to mate. And if you don't find a way to mate, it doesn't matter how fabulous you are. Those whatever traits you have are not going to exist in the next generation. And so sexual selection is that process of um evolution that is dependent on both our ability to attract a member of the opposite sex and our ability to compete with members of our own sex in order to do so.

• 51:13Speaker 0

  So that applies across the board, and all humans have been shaped by sexual selection because we all have these traits that we try hard to have these traits that others opposite sex finds desirable and that we that facilitate competition with their own sex. One of the interesting psychological consequences of that is that we end up with this really unfortunate circumstance whereby everything is relative. And what I mean by that is that it doesn't really matter how good of a guy I am. What matters is how do I compare to the other guys in my group? So if if all the men in my group are sort of worthless, lazy, stupid, and mean, well, it'll be pretty easy for me to get a girl because I don't have to be very special. I can be pretty awful, but I'm still the best choice she has.

• 51:57Speaker 1

  Right.

• 51:57Speaker 0

  Whereas if if all the guys in my group are really fabulous, I'm stuffed because she's never going to choose me. And so in the end, what people really care about, they're constantly looking around and asking how they stack up compared to others. And the reason they do that is it's super important for me not to fall behind everybody else. Because if everybody else in my group is better, it doesn't matter how good I am, I'm going to get left out of the mating game. And that's an unfortunate part of our psychology because it virtually guarantees in the modern world that it's harder to be happy. You know, I could work really hard and make a lot of money, and now I got more money than my this neighbor, but I then turn on the telly or I meet somebody who's got more money than I do, and I'm upset all over again.

• 52:37Speaker 1

  Yeah, totally.

• 52:38Speaker 0

  It puts us on this hedonic treadmill to be constantly comparing ourselves to others rather than just having a set standard of what we want to achieve.

• 52:45Speaker 1

  Yeah. Alain De Bodden from The School of Life talks about confidence in people being uh the highest uh identifier of confidence in someone based on their profession is the income and profession of their same-sex parent.

• 53:03Speaker 0

  Interesting.

• 53:04Speaker 1

  And that level of that level of comparison. But it's a it's so it's so well known, it's cliche, right? Keeping up with the Joneses, what is that?

• 53:11Speaker 0

  Exactly. Exactly. And so the thing is that if I, you know, imagine that I invented a new pill and it made you twice as smart and I gave it to you. Well, instantly you'd feel like you're some kind of genius, right? Because stuff you used to struggle with would be easy for you now.

• 53:24Speaker 1

  But

• 53:24Speaker 0

  imagine that you then left your office and you found out that I gave everybody two of them. And so you only had one, everybody else had two, and now you'd feel like an idiot, literally seconds later, because everybody else is discussing things you can't understand.

• 53:36Speaker 1

  Yeah.

• 53:36Speaker 0

  And so sometimes comparisons make perfect sense. You need to be at the same level everybody else's. But ironically, the same thing also happens because of sexual selection in domains that don't really matter. So imagine I told you, look, um, today is uh is your lucky day. I'm going to give you, just for being you, a hundred thousand dollars. Well, you'd be totally chuffed until you left your office to brag about it and you found out given everybody else a million.

• 54:00Speaker 1

  Yeah. And

• 54:01Speaker 0

  then suddenly you'd be pissed off. Why did you only give me a hundred grand? Well, it's it's ridiculous to feel that way because your hundred thousand still buys you whatever you 100,000 can buy, no matter what everybody else has.

• 54:12Speaker 1

  Yeah.

• 54:12Speaker 0

  But the logic of sexual selection now makes you think, oh, well, if everybody else got a million, I'm going to be left behind and the girl's not going to choose me. Is that

• 54:22Speaker 1

  that's an artifact of our sexual selection processing that's hacking our psychology for a whole lot of unrelated other processes, right?

• 54:31Speaker 0

  Well, it is. It's an artifact that has both these unfortunate consequences and also a kernel of truth. Because if I if I do give you 100,000, you are more attractive, but you're not more attractive if everybody else got a million.

• 54:43Speaker 1

  Yeah, that's totally right. Is this unique to humans? That's

• 54:46Speaker 0

  a great question. I mean, the thing is that animal fairness is something that cuts across all the animals that actually have a social system that can track these sorts of things. So the most famous example is um a study by Sarah Brosnan and Franz DeWall. And what they did is they train these um capuchin monkeys to um play this game where they would give the monkey a pebble, it would return the pebble, and they would give it a slice of cucumber. And so we know that the monkey regarded payment of a cucumber slice as fair because it actually learned the behavior in return for a cucumber. But now what they do in the critical point in the experiment is they have another monkey in the cage next to them. And when that monkey returns the pebble, instead of giving it a cucumber like they were like the first monkey got, they reward it with a grape. Well, monkeys, they far prefer grapes over cucumbers.

• 55:32Speaker 0

  And so then the question is what is our original monkey do now that it sees another one getting a grape for the very same behavior in which it's being paid in cucumbers. Well, when they then try to reward that animal with cucumbers, it gets really upset and often rejects the cucumber, refuses to take it. And this is a great video that Dual has where he's giving a TED talk, and you can see the monkey literally throw the cucumber at the experimenter as he's like as he's just totally outraged. And so it's it's a wonderful example of of an animal's sense of fairness. Now, I don't think that they think of fairness quite the same way that we do. I think that would be anthropomorphizing, but what I do think is happening is that they're going, well, I cannot accept a reward that's less than the reward the other one gets around being left behind. And of course, it's not doing that consciously, but that's nonetheless the psychology that underlies its rejection of a reward that it previously thought was just fine.

• 56:24Speaker 0

  Aaron Powell

• 56:25Speaker 1

  Yeah, I guess it's it's a very nuanced thing to be able to understand uh comparing different, you know, your car versus my motorbike, your house versus my boat. You know, that's very, very nuanced and that's subtle that that humans do. Whereas you know, grape grape versus cucumber, I think, yeah, you're that's basic. Yeah, absolutely. So I know that I I discussed this with Robin Hansen and he had he knows that this is such a contested area about how monogamous the um the particular individuals were around about this sort of time. Where does your current opinion lie with regards to monogamy within these these developmental tribes?

• 57:07Speaker 0

  So if you there's lots of variability. You've got um tri you've got groups of people who clearly um show very little signs of monogamy, and then you've got groups of people where you've got basically just monogamy. And of course you've got polygyny as well. My intuition, I don't know this, but I believe it is that basically our ancestors were on average serially monogamous with a little bit of shenanigans along the way. And so what we see quite commonly in hunter-gathers is uh monogamous pairing that lasts for anywhere from you know very briefly to seven or eight years, even or sometimes even for life, but usually not forever, and they sort of eventually go their own ways and then repair up with somebody else. I think that system was super common because it gains you advantage of not putting all your genetic eggs in one basket.

• 57:53Speaker 0

  And you know, when times change, maybe somebody else's genes would be a better fit for the new world. And um it it's consistent with our modern psychology that it's it's easier to maintain passion for somebody when they're new than than when you've been with them for a long time. But I don't think that polygyny was a super common system or any kind of polyamorous system. And the best evidence for that, I think, is is literally the size of our testicles. If you if you look at the testicles of all the great apes, you know, gorillas have very small testicles because they maintain a harem physically with the their body strength. They don't compete with no other male is having sex with their female, so and it doesn't actually take that much sperm to inseminate a female, so they can have small testicles. Chimpanzees have enormous testicles because everybody's having sex with her when she when she becomes fertile.

• 58:44Speaker 1

  Yeah.

• 58:44Speaker 0

  And so they basically need to wash out the guy before them and have sperm competition

• 58:49Speaker 1

  where

• 58:49Speaker 0

  their sperm um gets there first. And then human beings, our testicles are closer to a gorilla than a chimp, but they're way larger than a gorilla.

• 58:57Speaker 1

  Okay. And

• 58:57Speaker 0

  that tells me that that we're we're using where there is some sperm competition in our ancestral history, but nothing like the level that we see in chimpanzees. Aaron Powell

• 59:06Speaker 1

  There's an argument to be made as well about uh penis shape, right? That it creates a vacuum. Is that correct?

• 59:12Speaker 0

  Yeah. I that's a great question. I don't totally know. I've seen the experiment, and I've seen this sort of uh uh penis plunger system. It's it's super possible, right? It it's it's all these things evolve. And and in our case, our penises are way larger than the other great apes. And of course, we copulate with for much longer than the uh than most of the primates do. You know, there's exceptions with bonobos who have these constant orgies. But human beings, when they copulate do so for a long period of time. They do so when the female is not currently fertile because of course she's hidden her fertility signals. Ovulation is cryptic in humans, we can't tell. And so, and that gets human males to be interested in human females across the cycle, because otherwise they might be left out. And of course, that makes both sides engage in greater pair bonding, which Makes good sense when you look at the difficulty of raising human babies to adulthood, they take a lot of work by both parents.

• 1:00:06Speaker 1

  Yeah.

• 1:00:07Speaker 0

  And so I suspect that the penis may well be designed to try to help suction out the guy ahead of them, but but probably the primary purpose is for bonding so that they have a good time together and copulation can take quite a while. And so I think the reason our penis is so large is sexual selection, that that's what human females prefer. And so that's what human males are like. And that's why, of course, we're so obsessed with it. Aaron

• 1:00:30Speaker 1

  Powell And the ideal outcome or the outcome that evolution was wanting us to arrive at was greater pair bonding here, right? Was a a high level of investment between each other. Is that correct?

• 1:00:42Speaker 0

  Yeah. So the when you have a system like ours where um it takes so much effort to raise a human to, you know, a dozen years minimally to get them to be a reasonably effective unit who can forage for itself, that takes a lot of care and and takes two parents to achieve that. And it is the case that relatives also often work together. Um so particularly her her family will play a big role in helping raise the kids, and we see this in all sorts of places. But I do believe that part of what also underlies that is pair bonding and his willingness to look out for her and help her in return for her fidelity. And so I think that's a deal that that humans made somewhere along the way. It's not it's not a mission critical deal for our intelligence or our social intelligence, um, because I do think that's more happening at the group level, but I but it does appear to me to be the deal that we did strike.

• 1:01:34Speaker 1

  Well, it makes the most sense that the man cannot raise the the child. The man the man can't get pregnant, so they have to focus on what they can do. And right.

• 1:01:43Speaker 0

  Every both sides, what can you what can you bring to the table? And you have to remember that females, the obligatory investment of a male, the minimal investment he can put into a child is you know, a teaspoon of sperm. The minimal investment she can put into a child is you know, nine months of of um gestation and in ancestral societies, two years of lactation. Well, that's a huge investment compared to his. And as Trivers has shown us in the early 1970s in this parental investment model, that means that on average, men will compete very fiercely for females because of course they're competing for her investment.

• 1:02:17Speaker 1

  Yes. Yeah, I totally get that. So were there any other uh any of the discoveries that you came across while you were writing the book and researching it that you found that were really surprising?

• 1:02:30Speaker 0

  Well, what's surprising about to me is how many implications it has. So I'd be working on the book, and then I would get a a friend or a colleague who would say, Hey, can you come give a talk about leadership or about happiness or about innovation? And I would say, well, I don't work on that. And they would say, Well, but surely what you're doing must have implications for it. And so I'd say, huh, let me think about it. And it always did. Every time somebody came with one of those requests, I would give it a little bit of thought and I'd say, well, boy, it really does have implications for when and why we innovate, for how we lead, for what makes us happy. And so for me, the surprise was just how socially psychologically rich it is to understand and to think a lot about where we came from, because it tells us a fair bit about why we are the way we are today.

• 1:03:16Speaker 1

  Yeah. I I think one of the one of the definite conclusions that I drew from my conversation with uh Professor Robin Hanson was that the world around us has moved an awful lot quicker than our evolution can catch up with. And I think we kid ourselves into believing that we're a lot more sophisticated and a lot more in control, a lot more in control of our uh unconscious mind than we would care to believe. Um and you know, when you you're talking about you say 80,000 years ago was when there was a a a fairly big split off, and there was only 10,000 years ago, I think, in uh in and around uh the Philippines and stuff, where there was the final last non-sapiens homo species, is that right? The miniature uh diminutive size.

• 1:04:03Speaker 1

  In

• 1:04:03Speaker 0

  Florida's hat, yeah, I don't know exactly when they were um when that their last stand was. I have to admit, I'm not sure about that. But I'm I suspect you're right. I suspect that number is correct. Certainly we were interacting with Neanderthals 20 and 30,000 years ago. Wow. Um, and probably for quite a long time, right? Given that we so for example, the first Australians arrived 65,000 years ago. Well, by the if we got to Australia 65,000 years ago, we'd covered a fair bit of Asia and Europe by then too. We'd had a lot of interaction with Neanderthals by then, and presumably with Denisovans and others. And what what those others might be, of course we don't know, but there probably was a lot of intermixing and a lot of interesting blending because really we're interacting with cousins, so to speak. You know, our ancestors, some of them left, some stayed.

• 1:04:50Speaker 0

  Sapiens happens to be a product of those who stayed. But we're an interblended product with those who left.

• 1:04:56Speaker 1

  Yeah. Do you ever imagine what it would be like if we'd if there was still megafauna around megafauna animals, or if the if Neanderthals had managed to hold on, or if there was multiple different um uh homo uh subspecies floating around now, do you ever sort of fantasize about that or think about what it would be like in the

• 1:05:14Speaker 0

  modern world? I do, and I I worry that the story would not be a positive one because we're so tribal already when it's just other groups of humans who basically are the same as us, but with some very slight appearance differences, it's easy for me to imagine we could be really awful with people who really are distinctly different species. And it's easy, you know, given that that there aren't any left, I suspect we were awful with them, that we're super effective, and when we're not positively disposed toward others, we don't use that super effectiveness for good, right? We use it to exterminate them. We're genocidal toward each other. And so if maybe if if there were still all sorts of cousin species in the world, it would be a an easier pleasant, lovely place, but I I have the bad feeling it wouldn't.

• 1:06:02Speaker 1

  Yeah, I'm tempted to agree, but I do think oddly enough, the two conversations I've had with yourself and and Professor Hansen, very strangely I feel liberated when I hear them. I I think a lot of the time we beat ourselves up about being less in control of our unconscious mind and our actions and our motivations than we wish that we were. We get frustrated when we're in traffic and we get scared when we hear loud noises. You know, all of the emotions that we feel, loneliness and depression and anxiety and everything, both positive and negative, uh just artifact of uh a time that we evolved in that no longer exists, and we're kind of trying to make this primitive brain fit a modern world.

• 1:06:45Speaker 0

  No, that's absolutely right, because the greatest invention that we ever had was this idea of cumulative culture of learning from each other, of communicating that information over great times and distances, and that moves so quickly, and we're such generalists that we have the capacity to do that. But as you point out, that doesn't mean that our brain changes it anywhere near that speed. It just doesn't. And so the things that make us happy, the things that scare us, um, those those early things are still in there. And I guess what I would argue is the important thing to remember is that we're not totally at their mercy, right? They don't control us, but they are an important nudge that pushes us to feel jealous sometimes, to misbehave other times. And the key is to stop and ask yourself, well, why am I feeling this way? And why am I being so aggressive towards so-and-so?

• 1:07:32Speaker 0

  And why am I not happy with what I've got here when I used to be? And ask yourself those questions. And I do think that we can retake some of that control simply by virtue of the power of our frontal cortex, so to speak, and and and trying to say, well, I I can't let myself just be buffeted around by my unconscious mind, which really evolved a long time ago and is much better suited to a world that doesn't exist anymore. Aaron Ross Powell

• 1:07:56Speaker 1

  I totally get that. The race to the bottom of the brainstem, so to speak, needs needs to be counteracted. I did a I did a podcast with meditation expert Corey Allen, and he's got this wonderful term that I love using called the mindfulness gap. And he talks about in between the action occurring which you need to react to and your reaction is this mindfulness gap. And that one breath, that two breaths in between, it can make such a profound change. And you know that probably wouldn't be that useful if you're out in the plains. You want to be like a boxer, you want to react before you even think. Whereas now obviously being able to step in between ourselves and our reactions is actually quite a useful skill.

• 1:08:36Speaker 0

  No, that's absolutely right, because of course we no longer solve our problems physically, where speed is of the essence. We now solve our problems much more by negotiation and verbally. And so if given that, you're better off not necessarily flying off the handle right away and giving your immediate response, but saying, well, hold on. And I love that term, mindfulness gap. I've not heard that, but yeah, Corey's super smart, so I'm not surprised.

• 1:08:59Speaker 1

  It's it's absolutely perfect, I think. So the final question that I wanted to ask, I'm aware that you're unable to answer this with any real certainty, but at the moment we're moving forward towards a world of AI development and uh, you know, the the world is changing so quickly that I suppose any genetic mutations which were uh which did provide any particular advantages would have to be so generally applicable that they're probably not going to stick because of how fast the environment's moving. The environment now is different to it was 150 years ago and so on and so forth. So if you were to if you were to put your money where your mouth is, have you got any idea about whether we're going to see a different homo species before you know, is it going to be 500,000 years? Is it going to be a million years? Can you predict what would happen if you were to put your money money down?

• 1:09:49Speaker 0

  Well, that's a great question. And

• 1:09:50Speaker 1

  I'd be happy to predict it because I know neither of us will be here to find out if I'm wrong. And

• 1:09:54Speaker 0

  so I'll be able to state it with great confidence. But in truth, you know, our species is a new one. Homo erectus lasted for almost two million years and uh we've only been around for two or three hundred thousand, you know, it's hard to make an exact beginning point because of course it was a continuous process. And then the the question is is our incredible effectiveness going to be our undoing, or is it going to make us a huge success? And literally, you can't tell right now, right?

• 1:10:22Speaker 1

  It

• 1:10:22Speaker 0

  could easily blow us all up. We could develop a wonderful AI system that some random psychopath reprograms to kill us all. There's a there's a million ways it could go wrong, and only a few ways that it could go right. And we're trying to trick this sort of um, as you call it, this this this primitive brain of ours into living in this super complicated, super diverse modern world. So my suspicion is that if you fast forwarded a few hundred thousand years, we've got a 50% chance of having been really lucky, and we're now basically biologically the same that we are now, although we've done all sorts of tweaks to make ourselves live longer, and we're probably a little cyborg-like, machine enhanced and all that kind of stuff.

• 1:11:05Speaker 1

  Yeah.

• 1:11:06Speaker 0

  But you know, I I I also worry a lot that that we don't get anywhere near that far because we just do ourselves in, either with our own inventions that we're about to come up with that will then take over or just blow ourselves up because that risk is always there, and it's come close many times.

• 1:11:22Speaker 1

  Yeah. I think um I I had did a podcast with Professor Adam Frank, who wrote Light of Us Stars, and he identified that one of the byproducts of any world girdling civilization is going to be the level of global warming that we have because you can't have the energy you need for the civilization without the byproduct of the greenhouse gases and so on and so forth. And then if you read super intelligent, fantastic book on on AI by Professor Nick Bostrom from the Future Humanities Institute of Oxford. You know, it there's so many different ways that we can fuck this up. Like so many different ways. I know, and it's bizarre. It's so bizarre to think that if evolution hadn't if evolution hadn't created that mutation that took us from Homo erectus to Homo sapiens, the homo species may have lasted an awful lot longer.

• 1:12:12Speaker 1

  It's so bizarre to think that you can overshoot brain capacity to the point where it becomes dangerously proficient, and that can actually be your your downfall.

• 1:12:22Speaker 0

  Right. And the irony is that it's the combination of individual brains and our incredible capacity to connect them to each other. Because you know, I don't think a human on the planet could make an iPhone. But a lot of us obviously can make iPhones. And when we all tweak it together, which we that's what made us so successful in the savannah, was our capacity to work together. And that capacity could be the irony is that that which saved us could easily be our undoing.

• 1:12:46Speaker 1

  Yeah, that's so fascinating. I have got a final question before we go. One of my friends mentioned it before. He mentioned that a lot of people enjoy the smell of fresh grass. And wondered whether or not that was harking back to the fact that being out on the plains was a natural habitat for us. It's gonna be very, very difficult to work it out. But I thought that was an interesting and an interesting thought. That you know.

• 1:13:10Speaker 0

  Yeah, it's a great question because the what are our natural proclivities? You know, I argue that we all enjoy throwing rocks because even from very young age, because throwing stones was so important for our ancestors, and even into Homo sapiens, lots of um modern lots of human cultures uh until very recent times still um use stone throwing very effectively. And so the smell of grass is another example where that's a natural habitat for us. It there's um some very interesting work that talks about what makes a scene beautiful and what makes a place look stand out as a lovely place to live. And the evolutionary arguments are that things that afford us a wide view, we like that because we could see enemies coming at us, things that uh forests that are likely to have lots of game, all those kinds of things are our preferences that if our ancestors had, it would have made them more successful.

• 1:14:01Speaker 0

  Now you raise an interesting one, this idea of freshly cut grass, or just grass in general. And I suppose that that makes good sense because of course grass is a very unique species in the sense that it can dry out, the roots are still alive, but their animals won't be there. But once grass goes, once it rains and the grass goes green again, animals tend to gather. And so we may have evolved a proclivity to like the color and the smell of fresh growing grass because it's a good sign that dinner must be around the corner.

• 1:14:31Speaker 1

  Yeah, that's so fascinating. So what you're saying is that in terms of creating a nice landscape or a scenery potentially out of the back of a uh five fancy five-star hotel that the interior designers or the landscape designers need to be calling an evolutionary biologists and uh and psychologists to then come and consult and they can say, well, there would there wouldn't be a there wouldn't be enough buffalo over the far side, so I don't really think that we can have that lake in that area and

• 1:14:57Speaker 0

  exactly, and if they pay us a lot, it'll work out better for everybody. Fantastic.

• 1:15:01Speaker 1

  Well, that's brilliant. Um Bill, would you be able to tell the listeners where they can find you online, please?

• 1:15:07Speaker 0

  So certainly. So at this point, um, the easiest way to find me is simply to Google Bill or William

• 1:15:14Speaker 1

  Von Hippel, V-O-N-H-I P P-E-L.

• 1:15:17Speaker 0

  My book, The Social Leap is available now in the States and will be available soon in the UK, and is becoming available in lots of other places as well. And so Googling either of those two things is the best bet. I've set up a website for the book, but it's so rudimentary at this point, I would ignore it.

• 1:15:34Speaker 1

  That's fine. Well, I'll make sure that the link to all of your content is in the show notes below. I'll make sure it's the social leap is available in the UK on the 27th of December. So as I'm uh lounging around next to the Christmas tree, eating the remainder of my chocolates, I know what I'm going to be reading. Um I I can't thank you enough for coming on, Bill. It's been absolutely fascinating. Uh I th I feel like we could have gone on for for hours and hours. So we may need to we may need to come back and uh and give it another round two in the new year, but I hope that your book tour continues to be very successful in the US. Will you be back in will you be back in Oz in time for Christmas?

• 1:16:08Speaker 0

  Um No, I won't. I won't get back to Australia until February because we're covering a lot of ground. Um but uh I will get to the UK briefly. My sister lives in London, and so and my daughter goes to school in Wales, and so it's my hope to be noodling around there a bit as well. Um and it's been lots of fun chatting with you, and I would look forward to doing so again.

• 1:16:28Speaker 1

  Amazing. You'll have to drop me a message once you're in the UK, and if I can uh if I can come down and meet you for a coffee, that would be fantastic. Perfect. Cheers, Bill. Thank you very much for your time. Good to talk to you. Bye bye. Yeah, oh wait, yeah.