Nicholas Christakis and I are on the same page: We would definitely sacrifice our lives to save a billion strangers, perhaps even several hundred million, plucked at random from Earth’s population. But, for sure, not a thousand strangers, or a million. Those numbers seem, somehow, too insignificant. Christakis, the director of the Human Nature Lab at Yale University, shared this thought experiment on Twitter a few days ago as a poll that garnered over 2,000 votes: 12 percent would sacrifice their life for one stranger, 31 percent for a thousand strangers, 21 percent for a million strangers, and 35 percent for a billion strangers. “That’s completely implausible. I don’t know what to make of that,” Christakis said of that 12 percent. “I also don’t know what to make of the non-monotonicity of the responses—a larger fraction would sacrifice their life for a thousand people than for a million people. Nevertheless, thousands of people have answered, and it’s interesting to see that quite a few would sacrifice their lives for large numbers of strangers.”

Just how self-sacrificial should we be, especially toward people we don’t know? That question is just one of an array of biological and psychological riddles that Christakis tackles in his latest book, Blueprint: The Evolutionary Origins of a Good Society. It is more wide-ranging than his previous book, Connected, co-authored with political scientist James Fowler, which explored the power of social networks in shaping our lives. In Blueprint, Christakis marshals, in engaging and colorful prose, copious amounts of data—much of it stemming from his own lab—to make, in the end, a philosophical point about the fundamental goodness of humanity.

Courtesy of Nicholas Christakis

He also relies on his personal experience as a hospice doctor to make his case. “I have held the hands of countless dying people from all sorts of backgrounds,” Christakis writes in Blueprint, “and I do not think that I have met a single person who didn’t share the exact same aspirations at the end of life: to make amends for mistakes, to be close to loved ones, to tell one’s story to someone who will listen, and to die free of pain.”



When I spoke to him recently, Christakis told me, “What I’m attempting to do in Blueprint is very much in keeping with my liberal philosophy, which is to regard it as a book of sociodicy. I try to vindicate the existence of society, despite the evils and wrongs in society. It’s an account of why we live socially and why there is good in society, despite the manifest horrors. It’s both an empirical and a philosophical exercise, because first of all, empirically, I believe the case is compelling, but philosophically, that’s my belief about the world, that we are united by our common humanity.” At a time when tribalism is ascendant, we need to find new ways to appeal to the better angels of our nature.

I caught Christakis, as I discovered in asking how he was prompted to tweet that poll, at a particularly introspective moment. His explanation was a perfect segue into the fascinating ideas he articulates in Blueprint.





What prompted you to poll people about sacrificing their lives for different amounts of strangers?

It was a crazy confluence of events. It was the four-year anniversary of a Syrian archeologist who sacrificed his life to protect antiquities that ISIS was going to destroy. It made me think: I’m confident that I would sacrifice my life to protect my family, but were there other causes I would die for? Then there was the story of this asteroid that is projected, in about 10 years, to fly beneath some of our geostationary orbiting satellites. NASA doesn’t think it’ll hit earth. Would I sign up for a mission to save a billion people, like in the movies? Saving a billion strangers is the greatest good that any human being could ever have done. Then, I started thinking about how, during the Fukushima disaster, some elderly Japanese nuclear workers volunteered to take a one-way trip into their reactor to shut it down, because there was so much radiation. As I talk about in Blueprint, there are examples of extreme altruism that people manifest toward unrelated individuals—which is hard to explain in evolutionary terms.

All of these things were in my mind. I’m 57, so it’s a little easier for me to sacrifice my life than, let’s say, for you, at your younger age. I have raised my family. We have four children, who I adore. I’ve written books, done a lot of science.

I think we have innate capacities for goodness, and that they are marvels of natural selection.

I’d save a billion strangers. Not a million—that’s one three-hundredth of our population. And, like you said, I’m younger, and have a baby daughter. I would feel like I have a moral obligation to help raise my child with my wife.



I agree with you. That’s the thing—where is the line? There is no obvious way to answer these questions. But it is interesting the way ancient wisdom transmitted or embedded within stories can be relevant to them. We’re telling the story of Odysseus going to the underworld and talking to Achilles thousands of years later. They have a conversation, and they discuss the age-old dilemma that’s part of what we’re discussing right now. What’s more valuable, an unrecognized, let’s say simple, life that’s long on the planet, or a glorious, widely recognized, but short life? You could sacrifice your life and save a billion people, and you’d be remembered for time immemorial, but you’re gone. Achilles would say, “No, that’s stupid.” Better to “break sod as a poor farmer alive on earth than to lord it over all the dead in Hades.”

You write in Blueprint that, when you were with your grandfather at a frenzied political rally in Crete, he explained to you that leaders could prey on people’s sense of community and xenophobia simultaneously, in evoking feelings of injustice. People’s pessimism of human nature can also be preyed on. What gave you the sense that the narrative about human beings was too negative, and needed to be balanced?

I have spent a lot of time thinking about human nature, and to me it’s inescapable that much of the discourse about it is about our propensity to violence and selfishness and mendacity and tribalism. We read about warfare and colonialism and slavery. Every century is replete with horrors. This propensity to emphasize the dark side characterizes not only the person on the street, but also even social and biological scientists who explore the origins of behavior. I thought the bright side had been denied the attention it deserved because, equally, we are prone to friendship and love and cooperation and teaching. And these qualities must necessarily have been stronger than our propensity to all the evils, because if every time I came near you, you killed me, or filled me with fake news, or were otherwise mean to me or abused me, I’d be better off not approaching you. We would’ve evolved to live apart from each other. The benefits of a connected life must’ve outweighed the cost. It’s these benefits that I wanted to highlight in Blueprint.

Also in Sociology No Country for Old People By Robert Bazell Sweden did not set out to kill thousands of its older citizens. Nor did any country as COVID-19 swept across the globe. But Sweden’s unique and closely watched approach to the pandemic has spotlighted the tragic toll the coronavirus has...READ MORE

Freud wrote that civilization “obtains mastery over the individual’s dangerous desire for aggression by weakening and disarming it, and by setting up an agency within him to watch over it, like a garrison in a conquered city.” Was he right?

No, I don’t think so. It’s true that historical forces, like the invention of a police force, may function as a garrison to prevent us from being vile to each other. But we don’t need recourse to such historical forces to find the origins of goodness. I’m much more a Rousseauian than a Hobbesian. That quote from Freud is very similar to Hobbes’s argument, that a harmonious society requires a strong absolute authority. I think we have innate capacities for goodness, and that they are marvels of natural selection.

Why do you argue that the most important part of our environment is other humans?

Unlike the biological or the physical environment, the germs or the cold that can afflict us, the social environment is something that we, ourselves, make. That social environment is also a selection pressure. We evolve in response to it and become more social. You get this feedback loop when it comes to our sociality. The environment selects from among us those who are best suited to live in that environment, who then go about creating more of the environment. For example, we evolved to have friends. If you were a person who didn’t like friends, living in a society in which everyone else had friends, you wouldn’t fare so well. Friendly people make friendly societies, and friendly societies foster the Darwinian fitness of friendly people. I’m summarizing a longer and more complex argument, but that’s the gist of it.

You write a lot about how other social animals share aspects of what you call the “social suite,” which you argue is the evolutionary basis—the blueprint—of a good society, and spotlights our common humanity. What is the social suite?

I’m talking about evolutionarily shaped qualities or capacities that are inborn, shaped by natural selection, and expressed universally and collectively. There’s personal identity, love for partners and children, friendship, social networks, what I call mild hierarchy, in-group bias, cooperation, and social learning and teaching. Those are the eight traits of the social suite.

What about religion? That’s a human universal of great social consequence, no?

The reason that I didn’t include religion in the social suite—although there is no doubt that religion is a very powerful force, in terms of how people live together—is that you can be religious by yourself. But you can’t cooperate by yourself, for instance.

It’s an evolutionary luxury to be a unique person.

By studying animals, do we get a bigger insight into our own shared humanity?



Yes, because if we can share the capacity for friendship with elephants—which we do—we can share the capacity for friendship with each other. Our last common ancestor with elephants was 85 million years ago. These animals independently evolved to have societies with friendship and hierarchy and cooperation and identity and social learning. What that suggests is the very fundamental nature of these traits, which are shared by all humans—a point that is highlighted paradoxically when we find those traits in animals.

If there is a blueprint for a basic, functional society that has been shaped by evolution and that is part of our genetic heritage, why do societies ever fail?

When the social suite’s qualities are not expressed, it’s typically because some strong environmental or cultural force is impeding their expression. For example, by way of analogy, people have a body when they’re born that they’re innately prone to make. Kidneys make up a part of it. But if you were exposed to some environmental toxin, you might not have kidneys when you’re born. That absence, though, doesn’t say anything about the innate propensity of human beings to have kidneys when they’re born. The same thing might occur in certain societies. For example, when you have a secret police, like in Eastern Europe with the Stasi, you can constrain the innate capacity of human beings to befriend each other. What happens in East Germany when half of the population is informants? Well, no one trusts or befriends anybody, because everyone is worried that they are being ratted on.

Are we evolving to be ever more social, living in cities, or is there a ceiling?

That’s a very interesting thought experiment. I don’t think there’s a ceiling. We are getting progressively more social. I don’t think it’s primarily the cities per se that are doing that, although the cities probably play a role. As I speculate in Blueprint, it’s possible that this cultural artifact of ours, cities, could be a force of selection, acting over long time periods, now that great numbers of human beings live in them.

Cities could act like other known cultural forces of selection.

Yes. Take, for example, the most famous example of gene-culture co-evolution: Because we domesticated cattle and other milk-producing animals in the past three to nine thousand years, we’ve made milk constantly available. Those among us who can digest it in adulthood, which was previously a useless trait because we only drank milk from our mother’s breast, benefit from that. The domestication of cattle, in other words, has shaped the trajectory of our evolution. I think that it’s likely that the invention of cities is in this category. There are likely certain qualities—in the immune system, in our cognitive capacities—that fare better in cities than in rural environments. The fact that large cities are a feature of our natural environment may be making humans smarter. I’m not saying city-living folk are smarter than rural folk, but that the cognitive ability to live in cities, maybe in denser settlements, will have an advantage.

Yet, I think we would’ve become hypersocial even if we had not invented cities. Some people, like biologist E.O. Wilson, think that we may even be evolving to ultimately become like the eusocial insects, that eventually we’ll have castes of breeders and non-breeders, over hundreds of thousands of years. That’s too speculative for me, but I don’t think there’s a cap on how social we can be.

You quote a character from psychologist B.F. Skinner’s novel, Walden Two, talking about a planned community, who says, “The main thing is we encourage our people to view every habit and custom with an eye to possible improvement, a constantly experimental attitude toward everything. That’s all we need.” Do you agree with that sentiment?

Not directly, but I do agree with the idea that it’s good to be curious and try things out. I would like to encourage people to be adventurous. I’m not conservative in this regard at all. The kind of utopia described in that novel, when attempted in real life, was not very successful for a number of reasons, part of which had to do with the efforts to reject certain parts of the social suite.

If we are members of a social species, why do we have individual identities?

It’s an evolutionary luxury to be a unique person. Every human face is different. Why don’t we all have the same face? Well, it’s crucial to living socially. Humans have the capacity to communicate our individual identity with our faces. Not only do we have different faces, but you can look out at a sea of faces and tell the difference between a thousand different faces. The genetics of this are increasingly being worked out. The features of the social suite require the capacity to signal and identify unique individuals. An infant needs to be able to signal to its mother, “This is me. Feed me, not some other baby.” Or, if you are nice to me, I want to be able to reciprocate kindness to you, in particular. I need to remember who you are, to tell you apart from everyone else, and be nice to you in the future.

Yet often our sense of identity can be suppressed. You explain in the book how in-group bias or tribal feeling, for example, can lead to deindividuation, where the self becomes less salient. This can be good and bad. It can make us noble and self-sacrificing and quite deplorable.

We have this capacity to surrender ourselves to the benefits of the whole group. Now, that can also lead us astray, right? We can so identify with our own group that we demonize other groups. This is one of the most depressing aspects that my 10 years of thinking about human nature has led me to: Why can’t we just love our own group without hating other groups? Some people believe that they go hand-in-hand, and it’s inescapable. Other scholars think that we could evolve in-group cooperation with out-group neutrality. But in-group affection and out-group hatred seem entangled.

There’ve been many experiments with small children in this regard. You can take a group of 3-year-olds and randomly assign them T-shirts of different colors. The children know that they didn’t do anything to deserve these colors, and yet, once you assign them these colors, they immediately hate the other group. Those blue T-shirted children should be punished. They’re awful children. They shouldn’t get any toys. It’s crazy. You just scratch the surface of human beings, and you get this quality.

Do you have hope that we can ease the enmity that tribal feelings can encourage?

The literature on group mixing is complicated and often depressing. It’s not necessarily the case that mixing heterogeneous groups together improves people’s sense of our shared humanity, alas. It may depend sensitively on the circumstances or on the proportions of people being mixed. Some studies show that mixing increases inter-group identification and empathy, and other studies show that it decreases it. I summarize some of that in Blueprint. It may be the case—and this is very depressing—that we would reduce inter-ethnic strife by separating people, or it may be the case that we increase inter-ethnic strife by separating people. To what extent this is the case may depend on what we mean by separation, who the groups are, what the interactions are. There may be a lot of stuff that’s important about this, and that we need to understand better, if we’re going to reduce the ascendant tribalism that is so bedeviling our nation, and even the whole world, these days.

What’s more valuable, an unrecognized, simple life that’s long on the planet, or a glorious, widely recognized, but short life?

In a section on communal success, you write that “the only cures for anomie and doubt are faith and a deep contact with reality.” What do you mean by that?



This is another piece of received ancient wisdom, that the cure for disconnection is connection. That connection can come either from faith, or from actually going into the world and experiencing it and seeing it. Put another way, if you doubt something, and you want to stop doubting it, you’ve got two options. Either you can have faith in things unseen, or you can attempt to see them and remove your doubt.

Do you see our society dealing with a lot of anomie and doubt at the moment?

Yes, in some ways. This again provides fertile terrain for the emergence of a strongman, right? What do strongmen do? They say, “I alone can save you. You are lost in the wilderness, and I know the path”—the path to wealth, or to God, or to safety. It’s very tempting for people who are feeling lost to fall in line. In Blueprint, I talk about how one of the reasons we have ascendant tribalism in the United States right now may relate, in part, to the fall of the Berlin Wall and the decline of the Soviet Union. The existence of a superordinate threat can force former enemies together, to fight the common threat. We broaden our sense of who belongs in the in-group. I think that there’s some sense in which the fall of the Soviet Union may be having this effect in the U.S. of pitting us against each other, because we don’t have quite the common enemy anymore, and the loss of that common enemy—like Alexander the Great seeing that there were no more worlds for him to conquer—has led us to fall on each other. This is, first of all, bad politically and bad for the future of our nation, but it’s also inconsistent with my own vision, for whatever it’s worth, of what I think is a wise and sensible way to organize a civilization, which is to emphasize our common humanity.

How do we make sure to express the social suite in today’s evolutionarily novel societies?

I would like to live in a pluralistic society, but one in which there are, nevertheless, core values centered on the social suite—love, friendship, teaching. Incidentally, free speech falls under teaching. Because, in order to be able to teach each other things, we have to be able to speak the truth and talk to each other.

The Russians and the Chinese have different approaches to this. The Chinese have the great firewall. They try to stop information from reaching people, so people don’t see stuff that the government doesn’t want them to see. The Russians do the opposite. They flood the system with all kinds of crap, so people never know what’s true or false. In fact, one of the sources of our wealth and of our dignity as a people, which was foreseen by the Founding Fathers, was the commitment to free and open expression. We have to be able to test what’s true and what’s false. Otherwise, we just pass on falsehoods. It doesn’t work. Reality is the final mistress

Our inability to confront the climate crisis also causes a good amount of our anomie and doubt. What’s stopping us from expressing our cooperative instinct?

We evolved at a time when the scale of our social interactions was much smaller. My laboratory has done a lot of experiments over the last 10 years, exploring the conditions for cooperation, and how it relates to the size of groups. It’s very difficult to maintain cooperation as the size of the population with which you’re trying to cooperate rises. You can foster cooperation in groups of 10 or 100 with a number of interventions, or 1,000 even, but as you start to demand cooperation of a million or a billion people, it gets much more difficult. For instance, I was very flattered that Bill Gates recently reviewed my book, and he connected the arguments in Blueprint to some global threats, including climate change.

Are there ways that we can game our cooperative psychology?

There’s a lot of different ways. They have to do with something called “adding structure” to the population—so fostering personal connections between people, where everybody has their own particular personal connections, but everyone is connected to somebody else, who is in turn connected to somebody else. That kind of an intervention is very good for fostering cooperation, actually. This is very rare in the animal kingdom. We do it. Certain other primates do it. Elephants do it. Certain whale species do it. One of the reasons we’ve evolved the capacity for friendship, to befriend unrelated individuals, is that it facilitates the emergence, or co-evolves with, this capacity for cooperation.

If I ask you to be nice to everybody on the planet, you might not do that, but if I ask you to be nice to your friends, and if I ask every person to just be nice to their friends, then all of a sudden, everyone is being much nicer than they otherwise would have been. The amount of niceness in the society rises by taking an amorphous group of people and organizing them into a social network. Conditional on you not being a stranger, then I am more likely to have an opinion of you, good or bad. But the important point is that antagonistic ties are vastly less numerous than positive, friendship ties.

How does your argument that society is fundamentally good relate to historical accounts of a good life?

What I’m talking about is a set of prehistorical forces. I could’ve made all the arguments in the book about human societies as they existed 10,000 years ago. It is indeed the case, for example, as Steven Pinker and others have argued, that the Enlightenment fostered the emergence of a good life—everyone is living safer, longer, healthier lives because of philosophical, scientific, and technological innovations that continue to this day. But my argument is that we don’t need to rely on historical forces to provide an account for a good life. Deeper, more powerful, more ancient forces are at work that provide a foundation for us to understand the origins and meaning of a good life. We can relate to each other using these observations. Anyone who’s had any experience talking to someone, who seemed alien to them, very quickly can realize how much they have in common with that person. We should be humble in the face of temptations to engineer society in opposition to our evolved instincts. As I finish the book, I say, “Fortunately, we do not need to exercise any such authority in order to have a good life. The arc of our evolutionary history is long, but it bends towards goodness.” To me, that’s a very happy and—as it turns out nowadays—necessary thought.





Brian Gallagher is the editor of Facts So Romantic, the Nautilus blog. Follow him on Twitter @BSGallagher.

Lead image: GNT Studio / Shutterstock