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Nicholas Christakis joins the show today to talk about how humans are unique in that we have evolved the capacity for friendship.

Aaron Ross Powell
Director and Editor
Trevor Burrus
Research Fellow, Constitutional Studies

Nicholas A. Christakis, MD, PhD, MPH, is a sociologist and physician who conducts research in the areas of social networks and biosocial science. He directs the Human Nature Lab.

His current research is mainly focused on two topics: (1) the social, mathematical, and biological rules governing how social networks form (“connection”), and (2) the social and biological implications of how they operate to influence thoughts, feelings, and behaviors (“contagion”). His lab uses both observational and experimental methods to study these phenomena, exploiting techniques from sociology, computer science, biosocial science, demography, statistics, behavior genetics, evolutionary biology, epidemiology, and other fields.

To the extent that diverse phenomena can spread within networks in intelligible ways, there are important policy implications since such spread can be exploited to improve the health or other desirable properties of groups (such as cooperation or innovation). Hence, current work in the lab involves conducting field experiments: some work involves the use of large‐​scale, online network experiments; other work involves large‐​scale randomized controlled trials in the developing world where networks are painstakingly mapped. Finally, some work in the lab examines the biological determinants and consequences of social interactions and related phenomena, with a particular emphasis on the genetic origins and evolutionary implications of social networks.

The author of several books and over 150 articles, Christakis was elected to the Institute of Medicine of the National Academy of Sciences in 2006 and was made a Fellow of the American Association for the Advancement of Science in 2010.

What is human nature? It’s a question that’s intrigued philosophers for as long as there’s been philosophy. It’s also where quite a lot of political philosophy begins, imagining how our nature would have us live in a world before government.

How and why do humans cooperate? Why do we interact with people at all? Is there an issue with freedom of assembly? What kind of society is good for us to live together successfully?

Further Reading:

An Introduction to Public Choice, Free Thoughts Podcast

What Theory Won’t Tell You About Public Goods, written by Jon Murphy

Making the World Better, written by Aaron Ross Powell



00:07 Aaron Ross Powell: Welcome to Free Thoughts. I’m Aaron Powell.

00:09 Trevor Burrus: And I’m Trevor Burrus.

00:10 Aaron Ross Powell: What is human nature? It’s a question that’s intrigued philosophers for as long as there’s been philosophy. It’s also where quite a lot of political philosophy begins, imagining how our nature would have us live in a world before government. If humans have a consistent nature, then it matters a great deal whether it’s inherently cooperative and loving or competitive and violent, because the answer to that will impact what kind of politics we can reasonably expect and what sorts of institutions are possible and desirable.

00:37 Aaron Ross Powell: Our guest today, Nicholas A. Christakis of Yale University, studies human nature in a variety of contexts. He argues that our genes affect not only our bodies and behaviors, but also our societies, which are surprisingly similar worldwide. Humans everywhere experience love, make friends, have social networks, cooperate and create societies that are generally based on caring and trust. In today’s episode, we discuss how and why humans cooperate. We explore what we can learn about human societies from exploring different cultures, and even different species. And we ask whether our evolutionary heritage should guide us when thinking about political questions.

01:14 Aaron Ross Powell: Joining us today is Nicholas A. Christakis, he directs the Human Nature Lab at Yale University, where he is the Sterling Professor of Sociology, Medicine, Ecology and Evolutionary Biology, Statistics and Data Science and Biomedical Engineering. He is the co‐​director of the Yale Institute for Network Science. His new book is Blueprint: The Evolutionary Origins of a Good Society. Welcome to the show.

01:34 Nicholas Christakis: Thank you for having me. I’m noticing you guys are very soft‐​spoken. [laughter] Very soothing voices. I feel like late night chats.

01:43 Trevor Burrus: He’s got… Aaron’s got the NPR voice.

01:45 Nicholas Christakis: Yeah.

01:45 Trevor Burrus: Yeah. I’m a little bit more on the rock side, but you can come in here and yeah. [laughter]

01:50 Aaron Ross Powell: Okay, so looking around at the world today, especially the ways we all seem to increasingly hate each other, isn’t it kind of odd to write a 400‐​plus page book arguing that natural selection shaped us to live together in peace and cooperation?

02:08 Nicholas Christakis: No. First of all, I think the book, if anything, in terms of its sort of policy or political agenda, I hope is hitting the zeitgeist in the right way, which is to say, “Wait a minute, things are not as bad as you think and also, we are capable of being better.” So I don’t think, the book, I started writing the book 10 years ago, and it happened to be published now in this moment where we have century levels of inequality, socioeconomic inequality that are at century high levels, levels of political polarization which are extremely high, nationalism worldwide, we have climate change, we have a lot of problems, a lot of challenges, but at the same time, I actually think the story’s pretty good.

02:48 Nicholas Christakis: And I think it’s good in two ways, if I could. One is it’s not just good in the way that Steven Pinker argues, which is that over the last 300 or 400 years in a historical sense, because of technological advances that began in Europe, and then spread around the world primarily and philosophical moves that again began in Europe and spread around the world. Because of those Enlightenment innovations, philosophical and technological innovations, everything is better, we are healthier, wealthier, we live longer, it’s more peaceful, the world. I think Steven is totally right about those arguments. But my argument is that we don’t just have to rely on historical forces that give an account of a good life. Actually deeper, more powerful, more ancient forces are at work propelling a good society, and that for hundreds of thousands of years, evolution has shaped us to be good.

03:44 Nicholas Christakis: And so, despite all this badness that you alluded to, there’s actually some very deep and fundamental goodness in human beings which equips us with a capacity to live together well, and that’s essentially what I’m arguing.

03:58 Trevor Burrus: It seems a little bit different than the thrust of discussion of human nature for a lot of the Enlightenment or post‐​Enlightenment period where, whether it was the Hobbes‐​ian people are inherently bad or at least they’re gonna stab you in your sleep.

04:11 Nicholas Christakis: I’m a Rousseau‐​ian.

04:12 Trevor Burrus: Or a Rousseau‐​ian.

04:13 Nicholas Christakis: Yeah.

04:14 Trevor Burrus: Or you get into anthropologists and proto anthropologists of say the 19th and 20th century who discuss the “savage races,” I’m putting that in scare quotes, and how different they are from people and how, this is clearly not at all like the European, they may not even be the same species, obviously very race‐​based stuff, but overall, and then you get into modern anthropologists like Franz Boas and Ruth Benedict and Margaret Mead. It seems like they focused more on differences than similarity so do you think that was a wrong way of looking at it at the time?

04:44 Nicholas Christakis: Well, I mean, actually, yes, that’s also interesting, ’cause I’m very much a kind of humanist, a kind of universalist. I think that there is much more that unites us than divides us worldwide, and I think that it’s very easy to go around the world, whether you’re an anthropologist or a tourist and to go into a place and notice the differences. These people dress differently than we do. They have different language, they have different religion, they worship different gods, they eat different foods, they smell different. It’s different. And there’s a famous passage from Julius Caesar or something, it goes, “the Visigoths are different than we are,” or something, I’m making that up, my classics just sucks.

05:18 Nicholas Christakis: But anyway, the gist is people have always observed difference, but to me that’s not what’s interesting, because equally, when you go into a new society, you’re initially shocked by these differences, but then, if you pay any attention, you see that these people love their partners, they have friends. They feel good in the company of their friends, they work together to achieve objectives, they cooperate, they teach each other things. They have all of these universal traits, these good qualities that we humans in my view have been shaped by natural selection to have. And so I think in some ways it’s like we’re obsessed with difference, it’s like, I use the metaphor in the book of standing on a plateau at 10,000 feet and seeing two hills that are 300 and 900 feet and being so taken with the difference in the size of these hills and then realizing when you step back, that actually you were on a 10,000-foot plateau and actually, these are two mountains of 10,300 feet and 10,900 feet and that really those differences due to culture are superficial and tiny. You are focused on the erosion that was affecting these hill sizes, but actually there are these plate tectonic forces that are lifting up these mountains and those are the more powerful forces that shape our lives together. So that’s what I try to provide an account of.

06:42 Aaron Ross Powell: Why don’t we… So the example of the plateau and looking at the mountains makes sense, but why don’t we seem to pay as much attention to the similarities in the way that… When we go out into the world and I’m encountering new people, I go into a new place, I naturally seek out people with whom I have similarities. I’m noticing them then, right? These people share my interests and these people wanna eat at the same restaurant I do and they’re the ones I wanna befriend, but it seems like then when we take a step back and either we look at people who are more distant from us or we, as anthropologists, look at humanity as a whole or we’re studying them as subjects, that’s when the “let’s look at differences” comes out. And so what’s driving that? Is it simply that we don’t have something to compare ourselves to, so we just… It’s the water that we swim in?

07:33 Nicholas Christakis: It’s a number of things. First of all, just to back up a moment, there’s a long tradition, even in anthropology, of looking for cultural universals or privilege in difference, and those guys have been fighting amongst themselves about that for over a hundred years. And mostly the difference‐​based guys have been winning out because they’ve been more interested in differences and noticing how different cultures solve problems of living in a particular environment and so forth, but there have been very powerful voices within anthropology about cultural universals for a very long time, first point. Second, more generally in science, there are… A long‐​standing debate that even Charles Darwin, I think he was the first to describe it as lumpers versus splitters.

08:14 Nicholas Christakis: There are people, botanists, who go out and look at plants, and there are… Some of them are looking for unifying themes that unify all… These are all plants that are alike, and others that are saying, no, we need to understand every single plant and we need to engage in collecting every specimen of everything and focusing on the differences. And you can even think about it a little bit as scientists who are more interested in measures of central tendency, like what’s the average of a distribution, whereas scientists that are more interested in looking at the variance, what’s the spread in a distribution? So it’s important to recognize that even within anthropology and even within science more generally, there are powerful strands militating towards understanding commonalities and not just differences. Now, in terms of our innate desires to focus on difference, part of this has evolved as well. Our ability or our interest in defining who’s in and who’s out, us versus them, an in‐​group, is again one of our evolved capacities for living together, for better or worse.

09:20 Nicholas Christakis: Actually, this is… You’re zooming in on one of the more depressing aspects of our evolved sociality. Why is it that we are so interested in noticing differences and in identifying who’s one of us? Why do we prefer the company of people we resemble at all in the first place? And most accounts of the origins of this preference, in my view, tend to be tautological. They say, well, we prefer the company of people we resemble because we’re more comfortable in their presence. Why are we more comfortable in their presence? Because we resemble them. So you get this circular argument, and actually providing a deep account for the origins of homophily, and also the origin… Which is a distinct idea, the preference for people we resemble, and the origins of in‐​group bias, which is the sort of favoring our own groups in preference to other groups, is one of the things I do in the book, actually.

10:17 Trevor Burrus: Well, that was the next… It goes right to my next question, which is, you talk a little bit about Gemeinschaft and Gesellschaft in the book, which also… Friedrich Hayek, who we’re a big fan of here at Cato…

10:29 Nicholas Christakis: Very smart guy.

10:29 Trevor Burrus: He brought the response of… Yes, and on this question of in‐​group, out‐​group where you say that, on your Gemeinschaft you can maybe keep track of 150 people and you can have preferred personal relations within those, but a large open impersonal society can’t be like that, so it almost necessitates dividing to some extent, because we can’t hold the whole world in our head, right?

10:51 Nicholas Christakis: Yeah, I think there’s a difference between face‐​to‐​face relationships and more anonymous relationships where we interact with people as functionaries, as fulfilling a role, for example, as bureaucrats. And so in fact, I think often you find that when societies get… We experience… Often in modern society, we experience our everyday interactions as a kind of alienation. We interact with people, traffic police, vendors at stores, these are anonymous, faceless, impersonal interactions, and we experience them as alienating because we evolved to have real, face‐​to‐​face relationships with people that we really know. And so in a way we have… This is frightening, this is like being outside of your group and being with some other group that might not like you or might kill you, because these people don’t know you. But that’s different than the point about liking your own group and wanting certain kinds of social intimacy.

11:58 Nicholas Christakis: So to return a little bit to… To move away from the Gemeinschaft, Gesellschaft distinction and back a little bit towards the notion of in‐​group versus out‐​group, you might well ask, how and why did we evolve this desire to be with our own group in the first place, and there are a couple of theories about this. So let’s imagine you have 1000 people in some population, and you go to these people and you tell them, you need to cooperate. So from an evolutionary perspective, it would be fantastic if all these people could work together to achieve some objective. But you give this challenge to every member of this population, and it’s a prohibitive challenge, because why should they cooperate with other people? It’s too many people to cooperate with.

12:45 Nicholas Christakis: If they’re nice to you today, they might never see you again, the population is so large. They might not remember you. They can’t track 1000 different people. And so faced with that challenge in a group of 1000 people cooperating, nobody cooperates with anybody. And so, cooperation does not emerge in such a population. So if evolution could equip us with certain capacities that would allow us to cooperate, despite being in a population of that size, that would be strongly favored, the emergence of these capacities. Well, in fact there are a couple of such capacities. So one capacity… Both of them have to do with what’s known as “adding structure to the population.” So imagine now, you go to this group of 1000 and you divide it into 10 groups of 100 and you give each of them a flag. So there’s the purple flags and the green flags and the blue flags. And you tell everyone in the population, “You know what? Just cooperate with the people that are carrying your color flag.” Now everyone looks around. They only have to cooperate with 100 people. And they’re likely to see those people again and they can track those 100 people.

13:48 Nicholas Christakis: So now, all of a sudden all the blue flag people are cooperating with the blue flag people and the purple flag people with the purple flag people and so forth. So now from a population point of view, you’ve got a lot more cooperation. In the previous example, no cooperation, which is bad. In the current example, more cooperation, some cooperation. That would be favored. That ability to signal membership in groups and to detect membership in groups would be strongly favored by evolution, if it could emerge. And in fact this is one account of why it did emerge, one account of in‐​group bias. And this is known as “adding structure to a population.” Now this is extremely depressing to me, I have to be honest with you, like I don’t like the fact that we are this way. And we’re not the only animals that are that way, incidentally. [chuckle] But evolution also gave us another way of adding structure to the population, which is much more pleasant. And that is, it gave us the capacity to have friends.

14:43 Nicholas Christakis: Now, this is exceptionally rare in the animal kingdom. So many animals have sex with each other. They mate with each other. But we don’t just mate with each other, we befriend each other. We form long‐​term, non‐​reproductive unions with other members of our species. Namely, we have friends. This is very rare. It’s seen in us, certain other primates, elephants, certain cetaceans and a few other groups. But that’s it. So now we have evolved the capacity for friendship and how does that work? Well, you go to this population of 1000 and you tell them, “Okay, each of you are gonna have a few friends.” You have three friends, you have four friends, I have five friends, he has six friends, he has two friends. People have different numbers of friends and you create a network.

15:28 Nicholas Christakis: You add structure to this population, instead of every one of the 1000 mixing in with everyone else, people have their own overlapping sets of friends. And now you say, “You know what? Just be nice to your friends.” So each person is nice to their friends. And as a result of that you get more cooperation in the system, a different way of adding structure. So anyway, so the point is, is that we have evolved these qualities that are all interconnected and that allow us to work together. And one of those qualities, unfortunately, is this distinction that we are prone to make between us and them. And I’ll say one other thing and then I’ll shut up. I need to mention that this distinction between us and them, the cognitive ability to do that often is along arbitrary lines and that also gives us a little lever to address hatred in our society, which we can talk about if you want.

16:24 Aaron Ross Powell: I wanna come back to that. But first, this… What you just discussed gives a peek into this evolutionary psychology framework that you’re using here. One of the questions that people have about it or one of the critiques they have about it, is that what you just stated is you identified would seem to be traits that humans have that seem to be universal. We don’t know many people who don’t have friends and don’t seem to have a capacity for it.

16:50 Nicholas Christakis: About 5% or 6% of the population has no one that they can call or talk to. Yes. It’s very sad. But we can talk about that too.

16:56 Aaron Ross Powell: A distressingly high number. And then what you’ve done is you’ve told a story about how that might have been advantageous or might have come about, but that’s not necessarily the same thing as showing that that’s actually how it came about. And does it… So how do we know that it’s not just a story told to tie evidence together? And does it have any… From a scientific standpoint, does it have any predictive power? Can we do anything with that story once we’ve told it to say, “Now here’s a novel, new thing, new direction.”

17:27 Nicholas Christakis: Yes. Yeah, I can answer that question in a number of ways. First, a partial answer would be to say, what would you say if I told you that if we went and we mapped the social networks of elephants, that they have the same mathematical structure as ours, that if elephant friendships look just like ours. Our last common ancestor with elephants was 85 million years ago. That animal did not live socially. It was a small, shrew‐​like creature. And yet these elephants, by independent convergent evolution evolve social interaction structures that have very similar mathematical properties to ours.

18:03 Trevor Burrus: Well, that piece of data by itself wouldn’t necessarily underscore this that evolutionary psychology… ‘Cause you could say, “We’re the only ones.” Then you say, “No, actually, elephants too.” And it’s like, “Okay, well, there’s a different reason for both of these possibly or it could have come from somewhere else.” If you guys were the only ones, then maybe this evolutionary story is true. But we have nothing in common with elephants. So now it seems like we’re just sort of identifying arbitrary things.

18:26 Nicholas Christakis: No. We have in common with elephants the challenge of living socially and they solve the problem. So the argument is, there’s only one way of living socially, if you’re a mammal. Leaving aside the use social insects who are clones, which is a different challenge. No, quite the opposite. This finding evidence of convergent evolution on these traits and other mammals is very powerful evidence that this is not a “just so” story. Now, you might want to argue that friendship in elephants means something different than friendship in us and we could have that debate. Just like monogamy in birds may mean something different than monogamy in us and so forth. Nevertheless, the independent evolution of social monogamy in the primate order multiple times or the independent evolution of friendship across very disparate orders, to me is very powerful evidence that there is some problem that evolution is solving by equipping us with these capacities. And then we can go and look at the problem and say, “Okay, well, wait a minute. Whatever problem it’s solving has to be the same in elephants and in us.”

19:24 Nicholas Christakis: There are some predictions you can make and we’ve published some papers that say that if this was the way that evolution had shaped our capacity for friendship, it should also have given us certain other qualities. I can give you a couple of very quick examples. One has to do with the actual structure of the networks, which I’m gonna sort of explain a little bit, and the other has to do with something known as homophily, which is the fact that we prefer friends that resemble us. So on the structure thing, imagine that you have you have 100 people, and you have 500 connections that you could make between them. So on average, each person, might have, let’s say, five connections, but it could vary. So in your mind’s eye, you might be able to see, for example, a network emerging of the people connected to each other and you should also be able to see in your mind’s eye that there are different structures to that network, that you could arrange the people in a ring, for example, we could have a random jumble of ties or you could have everyone have the same number of ties or there are various kinds of mathematical structures of the network that you could imagine.

20:33 Nicholas Christakis: Now, it turns out of all the ways you could arrange the ties, there’s one way that you could arrange them that would give the group a certain advantage, namely an ability to resist epidemics. And how does that work? Well, there’s something known as degree assortitivity. A degree assortative network is that popular people befriend popular people and unpopular people befriend unpopular people. And a degree disassortative network is the opposite. Popular people befriend unpopular people. The airport network in this country is degree disassortative. You can’t fly from a small airport to a small airport, you have to go to a hub and then go back to a small airpot, so all the small airports are connected; all the unpopular airports are connected to popular airports and to go to them, you have to transit through the popular airport, as it were. That’s a degree disassortative network.

21:24 Nicholas Christakis: Human networks are not organized that way, the opposite. In the human networks, the New Haven airport is connected to the Lebanon, New Hampshire airport and then the Chicago is connected to Denver and those are the connections, okay, that’s how human networks are organized. But it turns out that if you organize a network in a degree assortative way it gives the whole population extra immunity against spreading diseases. Why? Because if you had a degree disassortative network as soon as the disease took root in any member of the population, it would go right to the most popular person and then down to everyone else.

22:05 Nicholas Christakis: So it turns out that degree assortativity, this property of popular people befriending popular people and unpopular unpopular, confers a kind of herd immunity to the population and lo and behold, of all the kind of networks that we humans could form ourselves into, we do this. And not only we do it but also dolphins do it. Also elephants do it, other species when they evolve networks also evolve degree assortativity as part of it. So you can make a prediction, in other words you could say, well, if it’s true that humans form friendships and that these friendships have been shaped by evolution, we would predict on first principles that this would be a property that evolution would favor, and then we go and we do an experiment and we measure it, we find, ah, they do do that.

22:52 Trevor Burrus: Well, it’s interesting too, because on Aaron’s question, it isn’t that evidence for that this happened historically, but then you’ve also brought in other tools to the game in your lab at Yale, sort of saying how does this actually happen, if you run people through these experiments.

23:07 Nicholas Christakis: Oh, yeah. In real‐​time, yeah.

23:08 Trevor Burrus: That doesn’t demonstrate that it’s what happened historically to humans.

23:11 Nicholas Christakis: Correct.

23:11 Trevor Burrus: But You can line things up and make inferences there. So how does that process that you do work and just in terms of fielding together sort of experimental groups, what are some of the things you learned from that?

23:23 Nicholas Christakis: Right, so if you were a mad scientist, which in some days I feel like I am. If you…

23:31 Trevor Burrus: Without any institutional review board…

23:32 Nicholas Christakis: Yes, exactly.

23:32 Trevor Burrus: And no morals whatsoever.

23:34 Nicholas Christakis: No constraints, limitless budget, no morals… If you were a mad scientist, what you would love to do, and you were interested in the kind of fundamental origins of human social order, as I am. What you would love to do is take a group of human beings as babies and abandon them on some faraway Island and somehow magically have them be raised in an acultural way, you don’t enculture them with any particular perspective, and then feed them, and then you come back 20 years later and you see, well, what kind of social order do they have. For example, do they have friends, do their networks look like ours etcetera, do they have hierarchy, do they have in‐​group bias, do they have all these qualities we’re discussing? And of course, you can’t do that.

24:15 Nicholas Christakis: So the book, in Blueprint, what I talk a little bit about is well, what are some initially, what are some approximations of that? What are some natural experiments that might be like that? Now, incidentally, that experiment that I alluded to has been called the forbidden experiment and powerful rulers for thousands of years have imagined such an experiment, usually with an eye towards detecting what kind of language is innate to us. So what they did is, is they would take, allegedly, they did do this, they would take some babies and give them to a mute shepherd up in the mountains to raise and then come back and see what language did the babies speak.

24:47 Trevor Burrus: So this would be like a king, or an emperor or someone who had the power to do that.

24:51 Nicholas Christakis: Yes, exactly, and Herodotus talks about how Psammetichus I 2500 years ago or something did this, and then I think King, one of the King James in Scotland in the 15th century did this. Allegedly in his case, he was interested in what language did Adam and Eve speak. It was kind of a theological or a biblical question, and allegedly those children when they were raised spoke passable Hebrew. So.

25:13 Trevor Burrus: I’m a little skeptical.

25:14 Nicholas Christakis: Yeah, me too, actually of this… I don’t know what the scientific… Anyway, so, if you’re a mad scientist you would like to do this kind of this forbidden experiment. You can’t. So in the book I talk a little bit about some proxies to that, and one is, one proxy is unintentional situations in which people were thrown together. For example, shipwrecks. And I look at 20 shipwrecks that occurred between 1500 and 1900, and that involved at least 19 people that were stranded for at least two months. What kind of social features did they develop when they were given this chance to make society anew? I look at many intentional communities, the communes in the United States, kibbutzes, settlements of scientists in Antarctica, communitarian movements of different kinds. I look at the settlement of Polynesia, when groups of people intentionally or unintentionally went to these islands. I looked at the Shackleton expedition, I looked at Pitcairn island, the mutiny on the Bounty, etcetera. I looked at many examples.

26:13 Nicholas Christakis: And the last thing I did, this is what you asked me about, which is, in my laboratory, we’ve developed some software that allows us to create temporary artificial societies of real people, where in this godlike way, we can… We can organize societies, and this software is integrated with online labor markets where we can pay research subjects a little bit of money to come and spend an hour in our lab, and over 30,000 people have participated in our experiments. For example, we can experimentally create societies in which the wealth is equally or unequally distributed. Same amount of wealth, in this group of people we give everyone the same, and in this group of people we give them different amounts. We set…

26:54 Trevor Burrus: Actual money?

26:54 Nicholas Christakis: Actual money to play, yeah, yeah. We set the GNE to be 0.2 or 0.4, whatever we want, and then we have the people interacting. We can test how… What is the effect of economic inequality on the social experience of these people? So, we’ve done many, many, many such experiments and we’ve looked at the origins of cooperation, we’ve looked at network structure, and so forth. And so, that too, those artificial societies, also is convergent evidence, because we find that when we organize the societies to have particular properties, they function better. And these properties we can test, experimentally test what those properties are.

27:33 Aaron Ross Powell: Does this mean you know how to fix Twitter?

27:35 Nicholas Christakis: Yes, I’ve been talking… So, Jack Dorsey, I’ve met him a couple of times, actually, and I’ve met with some people at Twitter, and I don’t know if I can fix Twitter, but I like Twitter very much and I would like to help fix it if possible.

27:50 Trevor Burrus: So, one of the experiments that you have in pictures in your book is trying to get people to pay for public goods, which is a libertarian political question that’s very interesting. And so, what did you find in terms of cooperation, on just whether that people would voluntarily give to public goods?

28:06 Nicholas Christakis: Yeah, so, we’ve done a lot of experiments with maintenance, the creation and maintenance of public goods. And I have, a very dear friend of mine who’s a very strong libertarian, who I really like a lot, and he challenges me. He believes, for example, that there’s nothing wrong with the private ownership of roads, for example, and he’s quite committed. [chuckle]

28:31 Trevor Burrus: There’s certainly nothing wrong with the private ownership of roads. [chuckle]

28:33 Nicholas Christakis: Yes, but to the exclusion of state ownership of roads. And so, he’s… And I really enjoy his mind, and I enjoy talking to him a lot and he really challenges me. He thinks that people should be able to sell their organs, of course, and their votes, and lots of ideas. Anyway…

28:52 Trevor Burrus: I know some people like that. Aaron, do you know anyone like that? [chuckle]

28:57 Nicholas Christakis: So, anyway, we often talk to him about the creation and maintenance of public goods. Now, from an evolutionary perspective, any tools that we could have evolved that would allow us to make the whole greater than the sum of its parts would be strongly favored in evolution. And the experiment you’re alluding to is an experiment in which we experiment with what we call social fluidity, which is the extent to which people can interact, with the freedom. Freedom of assembly, basically. Now, here’s how it works.

29:28 Nicholas Christakis: Let’s say you put a group of people in a rigid network, so you have, let’s say, 20 people, for the sake of argument, and you have a particular network structure. So, imagine like a little jumble of Christmas tree lights, the lights are people and the wires are the things, some kind of a complicated jumble that you put them in, and every spot in the network is a human being, and some people have two and three and four and five connections, whatever they have, and they’re distributed in the network. But let’s say you make that rigid, and you drop the people into that network, and you tell them, “Okay, you now need to cooperate with your neighbors. If you give a little money to your neighbors, we will double it and divide it among your neighbors. Everyone will benefit, but you’ll pay a little price. Of course, if your neighbors cooperate as well, then you’ll… And reciprocate, you will gain and the whole group will thrive.”

30:11 Nicholas Christakis: So, I drop you in this group, and what happens is is you find that pretty quickly, about typically about 65% of the people at the beginning will cooperate, will be nice to their neighbors, these are strangers to them, but their neighbors start taking advantage of them. Some jerks in the system. And so, after a while you’re like, “Why should I keep being nice to these people?” And so, they become jerks too, and before you know it, you start from a situation in which two‐​thirds of the people were cooperators, and by the end, everyone has become a defector. Well, it’s technically known as a defector. No one is collaborating and the society collapses. In fact, in the image, there’s a little few co‐​operators.

30:48 Trevor Burrus: Yeah, there’s on the edge three blue people left who are cooperating. Everyone else is red.

30:52 Nicholas Christakis: Everybody, and they’re keeping society alive, on the edge [chuckle], they’re just working together on the edge.

30:56 Trevor Burrus: This is what a society of jerks looks like, yes.

30:58 Nicholas Christakis: Yes, exactly. And so, in a different branch of the experiment, in addition to allowing everyone to decide at every time step whether to be nice to their neighbors or not, whether to cooperate or defect, we also give them a little bit of power to choose to keep their ties or to break their ties. So, we add a little social fluidity to the system. And what we find in that situation is that cooperation thrives. So, it’s not… In other words, because what happens is, is that you can cut ties to guys that are taking advantage of you and form ties to people that are nice, and just the existence of that opportunity, even if it’s not enacted, allows cooperation to flourish.

31:38 Nicholas Christakis: More generally, what we’ve been able to show across many experiments is that I can take a group of people and I connect them one way and they’re really sweet to each other, or I take the same people and connect them another way and they’re mean jerks to each other. So, these properties of cooperation and goodness are not just properties of individuals, they’re properties of collections of individuals, which we can experimentally control. Let me… Can I give you another metaphor?

32:01 Trevor Burrus: Please.

32:03 Nicholas Christakis: In a subsequent experiment, we experimentally manipulated how much social fluidity was there, so on one extreme we had a very rigid society where everyone is assigned their friends and neighbors, and can never… They’re stuck with them forever. And at the other extreme, you can imagine 100% social fluidity so that every given time step, you have new connections and everything in between. And what we found is, if that’s on the X axis is social fluidity and on the Y axis is cooperation, we found a parabolic shape, so that optimal group performance was achieved at middling levels of social fluidity. And many institutions in our society, I think, exist for this reason.

32:47 Nicholas Christakis: Example, divorce laws. In a society in which divorce is impossible, if you are married to someone who is mean to you, your only alternative is to also become mean. And so the marriage collapses. Nobody invests in the marriage and it goes away. At the other extreme, if you have a new partner every day, if your wife changes every day, why would you invest in this partner? She’ll be gone tomorrow. So marriage collapses. So what you want is a society in which divorce is difficult but not impossible.

33:14 Nicholas Christakis: You want a set of policy regimes that incentivize people to stay connected and invest in each other, but not be stuck. So this parabolic shape. Another example is the home mortgage deduction policy. So imagine that we were in like Stalinist Russia and everyone assigns you your house and you’re stuck with that house forever and your neighbors put graffiti on the house and put the garbage in the hallways. And why would you clean… Why would you make any effort to clean the public area because your neighbors are polluting it? And so everyone becomes a polluter in that type of situation. Or conversely imagine that every day you have new neighbors. You wouldn’t make an invest… Why would you clean your neighbors’ yard or your own yard, the sidewalk if you’re gonna have new neighbors the next day? So you want policies that make residential moves difficult but not impossible. You want to incentivize people to make an investment in their communities, but not make them stuck in their communities.

34:11 Trevor Burrus: It’s interesting, you went from, you’re like marriage law, home mortgage deduction. And I was like… Which generally I would not favor, I’m not in favor of, but I can see the point here in terms of building blocks.

34:20 Nicholas Christakis: Well, I used that example, but it could any number of social policies, you want… It’s this freedom of assembly issue. You want to preserve the freedom of assembly. You want people to be able to associate with those to whom they want, but you also don’t wanna make it so that the society has total anonymity. You don’t want a society in which every day you have new connections, you need some kind of stability and social connections, at least that’s how we evolved to manifest these qualities.

34:47 Aaron Ross Powell: So I think a couple of weeks ago, we did an episode on the role of science in politics, and one of the issues that we discussed was this question of science can tell us things, it can make descriptive statements about the nature of the world, but it doesn’t bring the normative angle into it, like the what we should do with it, and the policy making depends on a lot of things. And so what you’ve just described, we can identify some policies, but I guess the question is, how do we take what you’ve written, or what you’ve been discovering in your experiments and operationalize it in the world in a way where we can get the good stuff, like we can adjust the institutions this way so that we get better cooperation or more stable cooperation without drifting in the direction of the kind of prohibited experiments that we don’t want people doing. Where we’re just making radical changes in a bunch of people’s lives and kind of hoping for the best, or making changes that might not work. Like that connection. Because I can see a worry that we could take the science of this book, and we could get the authoritarian guy who’s like, “Okay, what I’m gonna do is I’m going to rebuild society along these lines.”

36:00 Trevor Burrus: I’m gonna mandate that everyone have five friends and 65% of people cooperate.

36:03 Nicholas Christakis: Right. So yeah, so I in fact discuss that head on in the last chapter of the book, because, if anything, what I argue is that you are right, that that type of authoritarian top‐​down specification of social order is bound to fail. So for example, you have societies that try to, like the Stasi in East Germany that tried to get rid of friendship by making everyone suspicious of each other. That’s not a strategy that is going to endure or succeed. In societies from Communist societies in North Korea or amongst the Khmer Rouge or even in communitarian communes and stuff, love of a family and a family life, is seen as a threat. Right? Because you’re supposed to be committed to the leader and the whole group, not have intimate devotion to particular individuals. So many of those groups, many of those societies try to eliminate, for example, love, which is another evolved capacity we have that I talk about, our capacity for love. They try to tamp down on that, or friendship where everyone’s supposed to dress the same, you address everyone as comrade, you’re not supposed to make distinctions between people. This does not work.

37:15 Nicholas Christakis: We human beings, we have these innate capacities, that cannot… Can temporarily be suppressed. Incidentally, they often lead to… The same objectives lead to oddly inconsistent policies. So for example, intimate sexual relations are often seen as threats to communal order. Because again, you would like be in love with your partner and not like feel loyalty to the group. So what do these communitarian movements do? They either go to the extreme of saying, “Well, we’re gonna have polyamory and everyone should and can have sex with each other,” a kind of orgy kind of model. Or they go to the route of the Shakers and they say, “Well, nobody can have sex with each other.”

37:52 Trevor Burrus: Makes reproduction difficult.

37:54 Nicholas Christakis: Difficult, right.

37:54 Trevor Burrus: Of even cultural reproduction.

37:56 Nicholas Christakis: Yes. Exactly. Well, the Shakers are a special case for that reason too. But the point is, both of those extremes are actually tackling the same problem, which is they don’t want family units, they don’t want people to feel devotion to their children and offspring and parents and loved ones and so forth. Anyway, the point, though, is that you can try to swim against this tide, but only with huge effort and pressure and only for so long. So I would argue that a deeper understanding of our evolved social nature and social order provides guidance or it provides an outline of the constraints against which social policy can operate, not a specification towards which social policy should operate. So I think that if you go out and you try to do things that are against what I call the social suite, these evolved capacities that we have, they won’t work.

38:52 Nicholas Christakis: You’re also… The is… Odd question that you put on the table, Aaron, is also something that I try to wrestle with, and this is a difficult problem that has been discussed in moral philosophy for a very long time. And here, I make use of the work of a moral philosopher by the name of Philippa Foot in the 20th century British tradition of moral philosophy, and she argues that you can avoid a kind of naturalistic fallacy. And I’m trying to provide an explanation for the evolutionary origin of a good society, what do I mean by good? And here, I make use of some of her arguments, and she says, for instance, you can define good by reference to the purpose of an entity. So, for example, we can speak of a good clock. What do we mean when we speak of a good clock? Well, when we specify what a clock is for, it’s to tell time, once we specify that constraint, then we can speak of this clock is a good clock or it’s not a good clock.

39:52 Nicholas Christakis: And she has a very famous essay which I think has a sentence in it that goes something like, “In moral philosophy I think it is helpful to think about plants,” and what she means by that is you can think about what it means to have good roots. So a plant has a certain purpose and these roots are good or they’re not good. And so, it’s in that way that I think we can speak about a good society, what kind of society is good for us to live together successfully.

40:22 Trevor Burrus: Human nature has not been terribly popular in some areas of the academy over the past 50 years and especially, I would say, 20 years, even as I mentioned, we were off air, Aaron and I went to school together, we went to Boulder, and we took some literary criticism classes and some of these things where you start talking about this is the right way of ordering a society, I’m hearing the, some professors I’ve had say this is just a centralism, right? There’s… Monogamy, pair‐​bonding, is pure construct of Western civilization.

40:57 Nicholas Christakis: But that’s not true.

[overlapping conversation]

41:01 Trevor Burrus: Or that this is taking pre‐​existing power structures and say, “We can’t have that.” Obviously, as you pointed out, whether it was the experimental communities of the 19th century in Michigan or Massachusetts, or you had hippy communes who said, we’re gonna take all this stuff away, we don’t need any of this stuff anywhere. We’re not gonna have any pair‐​bonding, we’re not gonna… Or kibbutzin, we’re not gonna raise our children, we’re not gonna have pair‐​bonding between… So people think that human nature has… And maybe it does have an inherently political ramification to it in some sense, like…

41:36 Nicholas Christakis: Well, I mean, this is the whole tabula rasa thing that people think that we are born without any innate tendencies, and that’s just patently false; not every way we live is culturally constructed. Now, of course, the culture is hugely important in human beings. I’m not rejecting the role of culture, but I don’t think that there’s much evidence for the claim that you can make any sort of human being, and you can make any sort of society. And we have much evidence against that, that belief and that claim. So, now the politicization of academia… [chuckle]

42:15 Trevor Burrus: And human nature in particular for, I mean, there’s a lot of ways it’s politicized, but the human nature thing is a particular one.

42:20 Nicholas Christakis: Yes. Well, I think people are worried that if you were to characterize certain ways of being, so for example, I’m very careful in the book, for instance, I don’t take a stand, notice, I’m speaking about love, I’m not, I’m not heteronormative, like gay couples can be in love, of course, and also I’m not even talking about strict social monogamy, like polyandry societies, polygynous societies, there’s love in those societies. So, what I’m arguing for is these fundamental qualities, and the list of my qualities, the qualities that I consider to be universal are love, first of all, identity, we didn’t talk about that, the capacity to be a unique individual, very ironically, is an essential feature of social life. You can’t organize a society unless, at least among mammals, unless… Non‐​clones, so amongst the ants and the wasps, you can, they’re genetically identical. So, in a way, it doesn’t matter who’s who. You’re just nice to everyone ’cause they’re yourself. [chuckle] But amongst us, you need to be able to track who’s who, us and certain other social mammals.

43:19 Nicholas Christakis: Anyway, identity, love, friendship, social networks, cooperation, mild hierarchy. We are a society that doesn’t do well, we are species that doesn’t do well when there’s no hierarchy or when there’s extreme hierarchy, in group bias, and teaching. Another thing we haven’t talked about, which is this miraculous thing that we all take for granted, which is that in every society around the world, we teach each other things.

43:44 Trevor Burrus: We have a predilection to transmit culture and to watch it, you just talk about mimicry, and babies, for example, will mimic, you wouldn’t have culture without some gene to transfer it off.

43:56 Nicholas Christakis: Yes, correct. So the…

43:57 Trevor Burrus: Cassowaries don’t have culture.

43:58 Nicholas Christakis: Yes.

44:00 Trevor Burrus: Maybe the most isolated being on the planet.

44:02 Nicholas Christakis: Yes, yes, yes, some birds have traditions, but the full‐​blown culture is sort of very unusual in the animal kingdom. But here’s the point, just to back up for a moment. So, most animals can learn, a little fish swimming in the sea can learn that if it swims up to the light, it will find food there. So they learn independently. Some animals do better than that, they learn socially. So you put your hand in the fire, you learn that fire burns, you’ve acquired some knowledge, fire burns, you paid a price, your hand is burnt, or I can watch you put your hand in the fire and I gain almost as much knowledge, but I pay none of the price. So social learning is incredibly efficient. You eat the red berries and you die. I’m like, “Oh, I’m not gonna eat red berries,” that’s like extraordinary. I can watch you do that and acquire this wisdom. Okay, so that’s social learning. This is uncommon in the animal kingdom, but we do something that’s even rarer, which is we teach each other things, we set out to teach each other things.

45:02 Nicholas Christakis: This too is a cultural universal, like love and friendship and cooperation and so forth. Everywhere you go, every human being on the planet, every society practices this thing. So we started our conversation talking about difference. Like, how people wear different things, or eat different foods or have different gods. Yes, they do, but that’s not to me what’s the interesting thing. What’s interesting to me is what we all share in common, and this then plays into a certain philosophical, even political commitment to what I would regard to be our shared humanity, our common humanity, we are all human beings and we can understand each other through this commonality, and I think that’s a part a salve to this kind of division that’s so ascendant in our society today, this notion that you can reduce people to the groups that they’re members of. It really is, I think, not only unsound from a kind of evolutionary point of view but also and politically dangerous in my view, but it’s not the kind of morality that I wanna practice.

45:02 Nicholas Christakis: I wanna believe that even though you’re different than me, I can relate to you as a human being and we have all these fundamental qualities in common. And so for me, it’s a rather happy, even though it’s very scientific set of ideas, it’s also a very happy set, at least for me.


46:24 Aaron Ross Powell: Thank you for listening. If you enjoy Free Thoughts, you can find our Free Thoughts discussion group on Facebook or on Reddit at r/​freethoughtspodcast, you can follow us on Twitter @FreeThoughtsPod. As always, please rate and subscribe to us on Apple Podcasts, Spotify, or wherever you get your podcasts. Free Thoughts is produced by Tess Terrible and Landry Ayres. To learn more visit us on the web at www​.lib​er​tar​i​an​ism​.org.