Monkey Business - Robin Dunbar, Dave Gorman and Jo Setchell

0:00This BBC podcast is supported by ads outside the UK. I'm Samir Patel, Editor-in-Chief at Quanta Magazine. Our mission at Quanta is to cover what we call basic or fundamental research in science and math. That means the kind of work that's driven by curiosity and discovery and the search for knowledge. We're interested in how and why everything around us works the way that it does. On our brand new show, the Quanta Podcast, you'll meet the writers and editors behind the magazine. and together we'll explore the biggest ideas and the tiniest details. Join me for the Quanta podcast, your weekly dispatch from the frontiers of science and math.

0:41Hello, I'm Brian Cox. I'm Robin Ince. And this is the monkeyest infinite monkey cage yet. It's key childhood memory for many to be walking around the zoo and getting to the monkey enclosure and then seeing that something is going on. You're just a young, innocent child, and you say, Mummy, what's that monkey hanging in that tyre doing? And she goes, look away, Brian, look away! There's nothing of interest here. But, Mum, I'm really interested. There's all things going... No, let's go to the chinchilla enclosure! But, Mother, I'm left with questions unanswered that might damage me in the future.

1:17I'll only be able to deal with particles, not living things. LAUGHTER

1:25Psychotherapists actually do believe that it is this experience that Brian and so many of you have had in the zoo that can lead to a rubber fetish, though only if the rubber has a six-inch tread. But today... I love the way that rippled around, because people were reading different images in and surprising yourselves. I think most people are just questioning a six-inch tread. That's enormous. What kind of tyre is that? That's just a tractor, isn't it? Not six inches. That's two or three inches at most. No, I don't. I don't know anything about cars. This is going to make no sense now, but anyway.

2:06But today we're looking beyond the tyre. Or indeed... LAUGHTER We're going through the tyre, which was one of Lloyd Grossman's less successful animal-based shows. Because we're going to look at what we can learn from, and I will use more Radio 4 language than my colleague here, the romantic behaviour of monkeys. We will be asking about the monogamy of the mandrel, the gregariousness of the gibbon and the temptation of the tamarind. Do monkeys appear to fall in love? How does sibling bonding vary? What gets a monkey hot under the furry collar and how often do we see them exhibit same-sex behaviour?

2:45Ultimately, what do we learn about ourselves by learning about the love life of monkeys? To aid and abet us, we are joined by a psychologist, an anthropologist and a cruciferbalist. And they are. Hello, I'm Robin Dunbar. I'm Professor of Evolutionary Psychology at the University of Oxford. And I've spent most of my life studying monkeys and humans and feral goats. And I think the most surprising thing that I've seen really with monkeys is just how Machiavellian and scheming they can actually be. They really are like watching humans. Hello, I'm Jo Setchel. I'm a professor of anthropology at Durham University.

3:29I study mandrels, who are a very large, very colourful species of monkey that live in the rainforest of Gabon in Central Africa. And the most peculiar thing that I have learned from studying those monkeys is that they use their vibrant colour to avoid conflict and that they have a scent gland on their chest which they rub against trees to advertise who they are, how high-ranking they are, and even their DNA. My name's Dave Gorman. I am what I am, and what I am needs no excuses. I've just learnt that a mandrill is a type of monkey and not a euphemism. And the thing I found most edifying from watching monkeys is the knowledge that they are literally too busy singing to put anybody down.

4:25And this is our panel.

4:33Let's first of all just start off, Joe, in terms of what is the kind of variety of, I suppose, romantic relationships that we see in monkeys, or sexual? It's hugely varied. So if we think about primates, all of the primates, it can be from a long-term bond that lasts decades through to a relationship that lasts seconds. The cutest relationship, I think, is the titi monkey. So they're one of the ones that form very, very long-term pairs. And as far as we know, which is not very far, but as far as we know, they're relatively monogamous in those pairs. and they sit in trees and twine their tails around one another.

5:15That's a romantic relationship. They sit together and twine their tails around each other. They're a very cryptic species, which means they hide a lot, so they hide in tangles of vines in the trees, but they always forget their tails. So you walk around in the forest and just see these two tails hanging out of the forest, and you know where the titi monkeys are. I think you're imposing some sort of cultural paradigm where you say they twine their tails and that's romantic because you might also say that's jealous and possessive. Yeah, total control. That's I always know where you are. And also, if you always forget your tail, to combine your tail with someone else's tail will improve the likelihood of remembering your tail.

5:53What's going on now? Absolutely. Robin, what about for you in terms of looking at what we might see? Let's say romantic, because even defining that can be quite difficult, can't it? We project something of ourselves onto that behaviour. Yeah, it's actually much easier to define friendships in monkeys because their friendships are very similar to our kind of friendships, the way they set them up. I guess romantic relationships, they kind of look the same, but, I mean, it does vary enormously from species to species and even within a species. Well, just like humans, I suppose. Different individuals, you know, have different intensities of relationships.

6:33There are introverts and extroverts. From an evolutionary perspective, Jo, so you talked about this whole variety of relationships, polygamy, monogamy. Is there anything that's favoured evolutionarily? Can we say, well, it would be better if a species only had monogamous relationships, long-term relationships, or what would you say, a large number of two-second relationships? They're all favoured evolutionarily, which is why they exist. But the kind of boring ecological answer is that it depends on the distribution of food. and it depends how many females can live in a group and how many females can live in a group determines how many males can be added to that group so if there's enough food for just one animal then a female has to live on her own she might or she'll have her kid with her but no one else if anyone else tries to join her make a group then there wouldn't be enough food it does get more complicated than this but that's the basic um then if you can have two females living together then they might allow a male to join them.

7:33There are advantages to having a male join you. You avoid harassment from other males. You probably do better in terms of protection from predators eating you. But at the same time the bigger the group the more likely the predator is to find you. And then if there's plenty of food then you can have a large group of animals and when there's a large group of females no one male can control access to them. It's complete chaos. It is complete chaos, exactly. With a bit of order underneath. Is monogamy more prevalent in a smaller group or in a larger group? In a small group. So where you have just one female, she might choose to share her area, we call it home range, with one male.

8:15And she might also choose to only reproduce with that one male. But she could also share her home range with one male and reproduce with other males. OK. So, Robin, you were just mentioning there the chaos. do you find yourself sometimes say you're out on a friday night and you look out the streets and you think um how much am i learning about the monkeys by watching the humans in the same way as i learn about humans from watching the monkeys actually to be fair a lot of the stuff that we've spent the last 20 years doing has been on humans in order to understand monkeys better you can do things with humans that you can't do with monkeys you can stick humans in neuroimaging machines and stuff like that and you can ask them questions give me an example of one experiment you might think right if we do that to some humans that will help us understand this particular group of monkeys more okay so the number of friends you can have is limited basically by the size of your brain that's a generic relationship in in across mammals um as a whole basically but in primates it takes a very quantitative form what we were able to do with humans originally was to look at your personal social network and tie that to the size of different bits of your brain.

9:32So it's a very, very strong relationship. So we don't actually need to ask you how many friends you've got, Robin. We just need to look at your brain and tell you. This is one of your most famous and most quoted pieces of research. So tell us, yes, that it is known as Dunbar's number. Dunbar's number, yes, yes. that's the limit on the number of meaningful relationships you can have, friends and family, and that's about 150 in humans. That actually consists of a series of layers of friendship, of greater and greater intimacy as they come in towards you. You've got a small group of very close intimate friendships and then bigger and bigger circles of less intimate friendships.

10:15So the average is 150. But how you are, between 100 and 250, correlates with the size of particularly this part of your brain, but also bits around here. That's the frontal cortex. Yeah, it's prefrontal cortex, but also the temporal lobe. And then inside that, there's this massive wiring connection, and it's the default mode neural network. And they called it the default mode neural network because they had no idea what it did. But when you put people in the scanner, brain scanner and told them to relax and not do anything then this this network became very very active and being as though a neuroscientist apologist and neuroscientist in the audience and didn't actually know what was going on inside people's heads they thought it must be the brain daydreaming and it's turned out basically when you're put in that sort of situation what do you do you think about friends family relationships the social network so the thing is going crazy because it's thinking about the network and then since we did those originally been about 25 studies now showing this in humans neuroimaging experiments have been done on three groups of monkeys so the same effect being shown at the individual level so through neuroimaging of like dave or brian or joe or me would we be able to see how shallow our friendship yes exactly Well, yes.

11:39Or even if you have any. So how does that scale? So if you go to, I don't know, let's say a macaque or pick a species, then how does it change? Does it change in a linear fashion if it's twice this? So you'll like this little bit because it's mathematical. And by the way, if you want any evidence of how actually functional that is, that it really exists as number, Somebody did an analysis of 61 million Facebook pages, counting all the friends on each of these 61 million Facebook pages. The average was 149. They've made the great mistake there of assuming that the people I'm Facebook friends with are people I'm friends with.

12:22In general, they are. Your 150 friends, as I mentioned earlier, are divided up into a series of layers. Those layers have very, very specific numbers. They're 5, 15, 50, and 150. So the 5 is what we call your shoulders to cry on, friends. They're the ones that will, you know, when your world falls apart, they will drop everything and come pick you up again. Turns out that those numbers are optima for the efficiency with which information flows through networks. And what's more, those are the numbers you find not only between species of primates, but also within primate groups, the structure of primate groups has exactly those numbers as well.

13:06So they don't run to the 150 because they don't have as big a brain as us. But for species like baboons and macaques and chimpanzees that live in groups of 40 or 50 individuals, they're substructured in exactly the same way as human social networks are. What are the other forms of behaviour that we might expect to be different depending on the cognitive ability to have that many kind of social connections. You've got what I call the line dancing problem. Imagine you're in a group, you're foraging through the grasslands or the woodlands of the savannah or the forest or whatever it is. How many people can you have in a group and still have the people at either end in time on a line dance?

13:52The answer is without music, very small. and that's this problem, it's the synchrony problem of moving in the same direction. It's really hard work for monkeys and apes and the few other species of mammals that have stable groups to try and keep the group together. And initially they do it just by sort of keeping track of their neighbour and keeping going. And it will only really allow you to work up to a group of about 15 maybe maximum and that'll be about five females and maybe three males, something of that sort of size and then the rest are kids. And you have to break through what's a glass ceiling at that point and produce something else.

14:35Producing something else has to do with grooming bonds. So at that point, they start to invest very heavily in social grooming to create these really intense friendships, bonded relationships that keep individuals together. So your friends will keep checking on you as well as you keep checking on them. And that'll do you up to about 30, groups of 30, and after 30 there seems to be another glass ceiling and you have to go through that. And that's when they start to use serious cognition. The brain really starts to produce major new kinds of cognitive strategies which allow them to figure out who's doing what with who.

15:16I think I've just realised why S Club 7 split up. because each of them realised that only five of the others would pick them up when they were down and resented the other two. Although I am assuming they were all capable of serious cognition, so maybe that's not right. How much does that affect, say, the Osmonds? Because there also you've got an actual genetic link as well, which would probably change the relationship, wouldn't it? Well, how much does it affect all family bonds if only five people are allowed in that inner circle? The minute you've got a six-person family, someone's in trouble.

15:51The way we've talked about it so far is quite mathematical, it seemed to me. But when we talk about, of course, human relationships, there's a large amount of choice involved. So I suppose I'm asking questions like, is there a pin-up monkey? Is there a handsome monkey that everyone would go for? Why are you bringing up, is there a pin-up handsome monkey, Brian? I just wonder if there's any self-interest here that we're watching. It's because it's written down here on the script. You wrote the question. No, no, you wrote that. I remember you doing that, crossing out the other one. Is there a monkey that wears a card?

16:25And you went, oh, I don't want to do that. So when I started studying mandrels, I was attracted to them because they're very colourful. And I wanted to know whether there's a pin-up effect, so whether the most colourful animal is the most impressive, perhaps attractive to females and so on. and I've been studying them now for decades and initially I did discover that the pin-up animal, the most colourful animal, has the highest testosterone, is the highest ranking and I thought, oh yeah, so I'm really figuring out something here. He's probably the most important and females do like to hang around the most colourful animal but there are many other things that come into it too.

17:08So there is his colour, there's also how nice he is. So if a male is brightly coloured but horrible, Females are just not interested. And it turned out much later, when I looked at their genetics, what they're really interested in is genes, and it's got nothing to do with the colour. So it's the males that are colourful? Males and females. So males are incredibly colourful, so we focus on that. But if you didn't look at a male mandrel and you just saw a female mandrel, you'd notice that she was very pretty and very pink-coloured. So pink nose, blue facial stripes, very pretty. And is it the females that are primarily making the choices?

17:45It's both. So yes, females definitely choose. Females have the advantage of being much smaller than males, which means that they can get around a lot more easily. I've seen males mate guarding a tree, thinking that their female is up the tree, when the female has jumped out of the tree about 10 minutes ago and has run down, jumped into another tree, run down, run out of sight and turns up later with another male.

18:14the through line we see is that the male remains the idiot i'm a female primatologist so yeah that's the conclusion and remembers to lift the tail up so it's not dangling down to give away where it is so that's so mandrels don't have that problem because their tail is only a few inches long and you mentioned genetics so in terms of the traits that will be attractive beyond the color what are the traits that the females are looking for? Immune genes, so the strength of the immune system, but not actually that. How do they gauge that? Through smell. So there's a link between the immunity genes and the smell of the animal.

18:53And they're partly looking just for a good immune system, but they're really looking for a match between their immune system and the male's immune system. Actually, this works both ways. is males also base their mating decisions on the female's genetic makeup. And in the end, the point is to make a better quality immune system in the baby. Has that changed in terms of the understanding of humans, though? Because I remember when we had Matthew Cobb on a while ago, and he was saying that actually the olfactory senses in humans during kind of dating mating is not quite what we thought it was before.

19:28Ah, so I think it's changed our understanding of humans in that we're not consciously aware of odour, but we're very unconsciously aware of odour. So it affects us enormously, it brings back memories to us instantly, but we don't necessarily think that we're influenced by it. So perhaps what we know now about primates and other mammals has influenced what we know about humans. But we're the ones who shower and put scent on and do stuff. So we're messing with a system to try and game it when actually, if we left alone, we'd probably mate more successfully with people who were better fit for our immune system.

20:09Not entirely, because your choice of... Well, I don't say your choice of perfume, but in general, women's choice of perfume, but I guess that applies to aftershaves in the case of men, is directly correlated with your natural smell from your immune system. So you like the perfumes, which actually enhance your natural odour. This is why, if I may give you some belated advice, Dave, don't buy perfume for your girlfriend. You're saying it's too late for him now. Because you'll buy something you like, not the one she likes. OK. Well, thank you for giving me a retrospective excuse. I'm never buying perfume for my wife.

20:54I've got to be honest with you, Dave. I remember when you gave her a box set of Lynx Africa. I'm not overly happy. Are you improving your chances? When you choose your perfume and you're saying this will be kind of matching with the smell, is that improving the chance? In a way, possibly. But there are other ways in which we also can pick up on our genes. So one is in the odour that we have on our body. Another is in the mouth when we kiss, for example. so you might wear some fabulous perfume that is created to attract the opposite sex, but it won't take you as far as kissing. Well, obviously, I didn't kiss my wife until she was my wife, and it was a bit late then.

21:44I remember that moment, you opening your mouth, going, better have fresh breath, links Africa. This leads us on neatly to the next question. It doesn't, though, does it? Because as we've just discussed, sexual behaviour in humans is extremely complex. Do we see such complexity in the sexual behaviour? We see lots of different sexual behaviours, so definitely, yes, both across species and within species. And also simply diversity of partner choice. So we have sexual behaviour between males and females, between males and males, between females and females. In some species, like the bonobo is famous for involving all the different age classes too, which we don't do as humans, or at least legally we don't do as humans.

22:31But is that right about... Because I know we're mainly talking about monkeys, but if we move on to apes as well, I remember being told a thing about the fact that bonobos would also have kind of a fashion sense, that they would sometimes pick up, like, say, a dead rat and wear it on their head and kind of parade around. And that's your idea of fashion. A parade scene. It fits, doesn't it? It does, yeah, yeah. So things like that, a kind of flamboyant display, which includes accessorising. I suspect that monkeys don't need that sort of accessory in the way that bonobos might, I don't know, because they have their own accessories.

23:06Like, they have bright red noses and blue stripes on their cheeks and colourful genitalia. Maybe they don't need a rat on their head. It's fascinating. So it's like they're describing the difference between the mating technique of Adam Ant and Rod Stewart.

23:27I've visualized it. Thank you for that.

23:34I'm Samir Patel, editor-in-chief at Quanta magazine. Our mission at Quanta is to cover what we call basic or fundamental research in science and math. That means the kind of work that's driven by curiosity and discovery and the search for knowledge. We're interested in how and why everything around us works the way that it does. On our brand new show, The Quanta Podcast, you'll meet the writers and editors behind the magazine, and together we'll explore the biggest ideas and the tiniest details. Join me for The Quanta Podcast, your weekly dispatch from the frontiers of science and math.

24:10The behaviors we've been talking about, so complex behaviors, but many of them driven by environmental factors and so on. How much can we read into the intelligence of the individual from the social structures and sexual behaviours that we see? Depends what you mean by intelligence. That sort of everyday physical world-type cognition, everybody has to do it in order to live in the real world. You've got to be able to compute how far is it from here to where Dave is sitting over there, in terms of when I leap off this branch to that branch to land in the right place and not land up on the floor.

24:48I love it when a bit of jeopardy is thrown into the show. But social intelligence, that's sort of separate. It exploits a lot of the same machinery, if you like, so causal reasoning and stuff. But the key to that seems to be that it involves what's become known as mentalising. It's the capacity to understand what's going on in somebody else's mind, essentially, or at least to be able to predict how they're going to behave in the future. and to manage and manipulate that to some extent. And that is extremely expensive in terms of neural processing time. And that's why you end up having to have this huge bit of the brain essentially dedicated to managing social relationships.

25:34So if you have a bright red nose, you don't need any of that because you can just look at someone else's nose and say, oh, okay, I know what's going on. A bit of a sniff to figure out all the information. And that's the difference between herding species, like feral goats, who don't have stable relationships and don't have stable groups because there's no point in learning the ins and outs and foibles of a particular individual because you may never see them again. All you need to know is, are they a bigger thug than you? Are they prettier than you? They've got a nice red nose or whatever the cues are.

26:07If you're in a stable group, you've got to do much more machinating, really, in order to keep everybody in the same place. Because the problem is, as I'm sure you all know, if you're too grumpy with your friends when you go out, they'll abandon you. So if you start being too aggressive within the group, you destroy the group. It's the skills of diplomacy. So, Joe, monogamy, when we see monkeys that are able to commit to monogamy, will we again will we presume that this this is shows various other forms of intelligence and indeed even possibly in terms of the rearing of the of of the babies so there's a lot of coordination involved yeah definitely so if you're living just as two and you either spend all your time together which can be involved coordination and giving up what you wanted to do to coordinate with your pair partner or there are some species lemurs actually rather than monkeys where they They coordinate within a home range, but they're not together.