← Return to search results
Examining Ethics Logo

The Kindness of Strangers with Michael McCullough

Overview & Shownotes

How did humans turn from animals who were only inclined to help their offspring to the creatures we are today–who regularly send precious resources to total strangers? With me on the show today is Michael McCullough, who explores this difficult question in his book, The Kindness of Strangers: How a Selfish Ape Invented a New Moral Code.

For the episode transcript, download a copy or read it below.

Contact us at examiningethics@gmail.com

Links to people and ideas mentioned in the show

  1. Michael McCullough, The Kindness of Strangers: How a Selfish Ape Invented a New Moral Code
  2. W.D. Hamilton and the gene for altruism
  3. Robert Trivers and reciprocal altruism
  4. Ancient Mesopotamia
  5. Humanity’s turn to agriculture (the Neolithic Revolution)
  6. The Code of Hammurabi
  7. The Axial Age
  8. The Golden Rule
  9. Peter Singer


Thanks to Evelyn Brosius for our logo. Music featured in the show:

The Zeppelin” by Blue Dot Sessions from sessions.blue (CC BY-NC 4.0)

Silk and Silver” by Blue Dot Sessions from sessions.blue (CC BY-NC 4.0)


Download PDF

The Kindness of Strangers with Michael McCullough

Christiane Wisehart, host and producer: I’m Christiane Wisehart. And this is Examining Ethics, brought to you by The Janet Prindle Institute for Ethics at DePauw University.

[music: Blue Dot Sessions, The Zeppelin]

Christiane: How did humans turn from animals who were only inclined to help their offspring and mates to the creatures we are today–who regularly send precious resources to total strangers? With me on the show today is Michael McCullough, who explores this difficult question in his book, The Kindness of Strangers: How a Selfish Ape Invented a New Moral Code.

Michael McCullough: I was really trying to understand how we got from a world in which we limited our concern for others’ welfare to family, friends, and members of our own small societies, to the world we’re in now, which is a world in which we don’t really think anything is strange, about wondering what we can do to help people in the developing world or the concern we should have ethically about future generations and their wellbeing, or even people on the other side of our countries or the other side of our cities that we’ll never meet, but we nevertheless have some impulse to try to take an interest in them to help them to ease their suffering.}

Christiane: Stay tuned for my interview with Michael McCullough on today’s episode of Examining Ethics.

[music fades out]

Christiane: I went to a religious private high school, which meant that evolution was not a big part of any of my biology classes. It was there in a kind of negative sense–we were taught that Darwin’s theory of evolution did not mesh with the Biblical account of human history, which was the “true” account of human history. In spite of that, and thanks to my scientist father, from a pretty young age I’ve appreciated the beauty of Darwin’s theory and developed an interest in the ways in which human bodies have changed over the course of millions of years.

I was fascinated, then, by Michael McCullough’s account of our psychological evolution and how our minds–not just our bodies–have morphed over hundreds of thousands of years. His book, The Kindness of Strangers: How a Selfish Ape Invented a New Moral Code stretches from hunters and gatherers who wandered across the earth in nomadic bands to the present day. He focuses on the question of how humans went from a fairly limited sense of morality to developing sophisticated moral codes that help us answer the complicated ethical questions we’ve faced as societies get bigger and more complex.

I spoke with Michael in December of 2020.
[interview begins]
Christiane: Most of the listeners will understand that we’re a social animal, that we’re biologically programmed to be social, but that doesn’t necessarily mean that we’re biologically programmed to be kind to one another, right?
Michael McCullough:
We most surely are programmed for certain kinds of altruism toward others, but I actually don’t think the mechanisms that those evolutionary dynamics give rise to can really explain the thing I want to explain, which is, you know, why is there an effective altruism movement? Why is there a UNICEF? Um, and I don’t think the evolutionary explanations that evolutionary biologists and evolutionary psychologists trade in, I don’t think those theoretical tools are up to the job of explaining that kind of cool stuff.

Going back to Darwin actually, evolutionary biologists have been interested in what they call the problem of cooperation. And the problem of cooperation is that it shouldn’t exist and yet it does. And the reason it shouldn’t exist is because when I render help to some other individual, it comes at a cost to me, and it comes as a benefit to the other individual. And those are the currencies that natural selection operates on. It operates on costs and benefits. So we do a sort of short- uh, sort of a shorthand thing and we talk about sort of costs and benefits as a matter of economics, but natural selection is an economist too. So anything that I’m doing, any energy I’m expending, any resources I’m expending to your benefit, are resources I couldn’t convert into reproductive success. So the question is why, why do we invest in others?

And so this problem sat around actually in, in evolutionary biology for a hundred years, um, with people kind of knowing sort of what an answer was, which is, well, we take care of our family, you know, um, that’s sort of how we get our interests into the future. So there was a recognition that our genetic interests live on through our offspring, but no one really knew how to formalize that. But in the 1960s, uh, an evolutionary biologist named William Hamilton worked out the math on this.

Suppose you have an adaptation that causes you to do something nice for other individuals, and this is beneficial to them. What Hamilton showed was, that’s a gene that could evolve by natural selection.

So if you think about this, it’s like, uh, let’s say I’m doing something that’s harmful to me, but it creates three times that amount of benefit to another individual and the class of individuals I’m helping are 50% likely to share that gene as well. Who is the class of individuals in my world who are 50% likely to have a gene that I possess? Well, my offspring will have a 50% likelihood. So I can reach out into that class of individuals called my offspring. And if I’m doing something that costs me a unit, but it makes them three units better off, and we multiply that cost benefit ratio by the likelihood that they have that gene, that satisfies the requirements for that gene to evolve. You get three times the benefit I do, and there’s a 50% likelihood you’ve got that gene.

So in a sense, um, I produce one fewer copy of that gene, but you’re producing another copy and a half of it on average, that gene is going to increase in frequency. So the population will become more altruistic because of relatedness and because we’ve got this cost benefit ratio that is favorable given, given the degree of relatedness. So what does this all mean? It means we evolve to take an interest in the welfare of our families, and that’s a kind of altruism. Um, so that’s the first way we explain the evolution of altruism. There’s other models we can get to, uh, if you feel like it, but a lot of them have to do with reciprocity and friendship.

I actually, yeah, I do want you to talk about reciprocity just a little bit. I’d like you to explain why humans have this idea of reciprocity and how that works in our bodies?
Michael McCullough:
So another mechanism in addition to kin altruism, as we often call it is a dynamic called reciprocal altruism. And here, we’re just trying to explain how it could come to be that you end up helping individuals who are not close genetic relatives. For what reason might we have a motivation to help individuals who are non-relatives? Um, so who don’t share that gene for helping in common. An evolutionary biologist named Robert Trivers, uh, in 1971 figured this one out. And, and what he was able to show is that if you have a gene that causes you to provide a benefit, uh, at a suitable cost benefit ratio, again, like, like with Hamilton, it’s cheap, cheap for you to give, but really beneficial to receive. And in that giving process, you create some kind of motivation in the recipient that then motivates that recipient to repay you in the future to provide that same kind of benefit to you in the future. Then that’s a gene that’s also on the move.

And, you know, you can think about this as buying low and selling high. I’m going to buy your friendship in a sense, I’m going to buy it low, you know, by providing a benefit to you that’s, you know, it’s cheap for me to provide, but it’s really valuable to you. So what have I bought? I’ve sort of bought your gratitude and as a result of how I’ve helped you, if that, if that kind of caused you to make a memory that I helped you, and that it also motivates you in the future to help me, then even though I’m sort of in the immediate term, I’ve paid a cost in order to provide a benefit to you, which makes it look like I’m disadvantaged in the eyes of natural selection.

If that favor I’ve given you repays itself over the life course, then over the life course I’m better off for having paid that small initial cost. It’s really like investing in a stock, actually, reciprocal altruism works very much that way. I’m going to sort of buy your friendship or your faithfulness so that when I need three units of benefit, you’re willing to pay that one unit cost in order to make me better off. And so through the course of a lifetime, we establish this sort of partnership. And each, each, at each, with each exchange of benefits and costs, we’re better off, you know, on average, we end up better off over the lifetime.
I think this is where the problem of your book comes in, right? Because then how do you explain a one time $500 donation to Live Aid or me sending bottled water down to New Orleans during hurricane Katrina? Right? I don’t know anybody in New Orleans, I’m from Indiana. When does that shift start? Or, or have we always been programmed to want to help even people that we’ll never ever see?
Michael McCullough:
We have to do a little bit of projection backwards and work with, uh, you know, a fairly sparse anthropological record, archeological record to try to figure out how we did think about complete strangers prior to moving into cities and chiefdoms and stuff like that. Before we got into big collectives. My read of the existing data is that we lived in small societies. Uh, you know, if you think about the organizational units that we evolve to live in, there’s the nuclear family. Then there’s this kind of band of, you know, a couple of family groups, maybe three or four family groups that lived together for a season. And you can think of them as sort of a temporary neighborhood or something like that. So it’s this sort of temporary nomadic band.

And then above that, you’ve got the cultural group, you know, you can think of, this as people who speak your language. And that could be a thousand people. Maybe several thousands of people. That is your social universe. That is the entire world of people that you could in principle care about. And the reason you could in principle care about them is because the whole Kevin Bacon thing, the whole six degrees of separation thing. I know your brother’s wife, who you also know or something like that. So we have just a couple of degrees of separation.

Then I have some incentive to be nice to you, even if we’ve never met. And, you know, perhaps we’ll, we never will see each other again, but we exist in this dense network of friends, of friends, of friends. So you can think of that as the mating pool, the marriage pool, you know, this is the class of people you couldn’t in practice interact with. So what do we know about how people interact with people from other ethnolinguistic groups? This is where the data are contested. But my read is that we tend to, uh, regard those people with suspicion and hostility. We don’t speak together. We don’t eat together. Our customs are different. Uh, and in general, um, our relationships are either regulated by just keeping apart, uh, and avoiding conflict, or when we come in to, if we bump up against each other too closely, to engage in conflict.

So I think we evolved not only to not treat that distant other kindly, but in fact, to regard them with suspicion and possibly hostility. So I think that’s the psychology we come into the modern world with where we are, we’re really indifferent to people whom we can only imagine are out there. And that’s the psychology we bring with us to the first city-states, to the first chiefdoms, to, uh, Mesopotamia, the cradle of civilization, where societies start to get really big. And that’s where we start to have, I think, the first tangible problems of suffering strangers and us not being equipped with kind of evolved psychological hardware that would motivate us to care for, for their wellbeing.
We come into the modern age with this psychology, but you’re talking about what era? BCE?

Michael McCullough:
We’re probably talking about 13,000 years ago, when that transition started, then we’re in the first cities, you know, maybe 8,000 BCE. People move from a really communal way of life to when they start farming and cultivating grains, primarily. You see that they start to privatize their resources. We’re starting to move from a communal understanding of how to make a living out of the world, to one that’s really more organized around immediate family or extended family. The way you make a living as a farmer is you can do it all yourself. You can do it with you and your family, so you don’t need to coordinate the sharing.

So life begins, begins to get private and lineage based. Then you project that forward into these first, these big city States, and that whole thing just explodes. It becomes about home and hearth and your immediate trading partners, and maybe your neighbors. You don’t know the people, you know, in your city of 10,000 people. You’re not going to interact with the people on, you know, clear on the other side of the city. This is the first, I think, the first real challenge for our evolved mechanisms for caring that they’re just not built for worlds of 10,000 strangers.
And maybe even worse than that, this is when, this is when you start to see what we would call poverty.
Michael McCullough:
So then how do you explain what you call the age of compassion?
Michael McCullough:
The solution in those early societies of the ancient near East is legal codes. It becomes offensive enough to see the amount of inequality in society that these God Kings of Sumeria and Mesopotamia began to issue these grand legal codes. Code of Hammurabi, of course, is, is, is the example that, that we, you know, that comes to mind, you know, immediately, but it wasn’t the first, there were others. What they all seem to include are regulations against exploiting the very, very poor. Life in those ancient city-states–as is increasingly the case in the United States, for example–success and failure becomes so much a matter of luck, good luck and bad luck that is heritable.

So the first land, your, your family is able to acquire and enclose and privatized, it’s going vary in quality from, and, location, from irrigation and so forth from, um, your neighbors. This is just random luck. Some land will be more productive than other lands. We’re privatizing this stuff, so it’s no longer communal, so we’re not pooling risk among large collectives, that’s a kind of bad luck just as a starting initial condition. But then there’s just sort of random bad luck that, I mean, this is all about the small numbers, right? The breadwinner of a family dies, a son dies, who was, you know, critical for helping the farm to run and so on and so forth.

This, this kind of bad luck just in, you know, or good luck multiplies across society. So you have, you have widows and orphans who have no one to take care of them out of bonds of friendship or family: easy to exploit. And, uh, it becomes so outrageous, and I think so demoralizing that these ancient despots realize like we have to do something to limit how they’re being exploited. So you get these legal codes that say, we can’t charge exorbitant interest rates. If somebody becomes your indentured servant, it can’t be for a lifetime. If you take someone’s property as sort of, if you pawn it, you have to give them the chance to buy it back in the future.

So you see all of these sort of tender mercies developing that are designed to limit the ability of the very fortunate and wealthy for, to just grinding the very unfortunate poor into the dirt. So from this age of these first large cities, we move into an era that, um, social scientists and many philosophers and historians called the axial age. And this is a period probably, you know, between 800 and 200 BC. When you see this flowering of the world’s religions, the religions that are still practiced today, you know, Judaism, Buddhism, Hinduism, and then classical Greek thought. In each of these societies, you see the development of a golden rule for the first time, a notion that everyone around you, no matter their identity is entitled to the same kind of consideration that you would claim that they give to you.

You become morally obligated during this so-called axial age to practice what’s, you know, what we now recognize as the golden rule. So what you see is that in each of these societies, spirituality becomes really deeply tied up with sympathy, with compassion, in some sense to be spiritually right, or right with God means you have to extend your compassion to the entire world. So we get the golden rule and we get all kinds of institutions during this era that are responses to this new ethical insight. So you see in ancient classical Greece, you see kind of the first, um, veterans affairs, the department of veterans affairs. You see the first large work programs, the first disability insurance programs in Israel at the time after the Israelites returned from the Babylonian captivity. You see them bringing with them and innovating ideas like the need for institutions within the society that helped to meet the needs of the poor, of the orphans and the widows.
The golden rule, these, these ideas around compassion, helping, helping others, it is new, right? Um, in terms of humans as animals, it’s a thing that we have created, right? No matter, it might be 2000 years ago, but it’s, it’s never the last something that might not necessarily have been with us since the beginning of our evolutionary journey. Right?
Michael McCullough:
That’s right.

You could have a rule that works in your small scale society that’s like, you better pay those people back because you know you’re going to need help from them in the future. Like if you are lazy today and you decide to not go out and work, well, you’re setting yourself up for being abandoned or being, being shunned, not getting their help in the future. So in this society where there’s, you know, what comes around, goes around, it’s really easy to see the logic of helping other people. But when you get to this world where you just, you just know you’re never going to see these people again, but you know they’re out there, you know they’re hurting, that takes a different kind of psychological raw materials to get the conviction that you ought to be caring about complete nameless, faceless strangers.
The golden rule is, is, is one of the most revolutionary insights into ethics that we have as humans, right?
Michael McCullough:
And we’re just fine tuning it and making it better and fixing the problems that, that come up with this. By the last half of the, the 20th century, we’ve evolved pretty far from those, those early years in the age of compassion, right? Those early years in, in our big, in our first big cities. And we get, we get a guy named Peter Singer, right? Who, who, as you say writes one of the most important works in terms of kindness of the 20th century. So, so what are his ideas and what kind of new, what kind of new era does he spark?
Michael McCullough:
Right. Uh, so Singer, uh, is an ethicist and, uh, has spent his life trying to, his, his career trying to trace out what the implications of utilitarianism are for the world of ethics. One of his major contributions was an essay in which he made a very, very subversive, but very simple argument. And, uh, in this essay, he basically just presents the idea that if, you know, you passed by a child who was drowning in a little pond, you know, a little city pond, and you were on your way to work and you were busy and you had your best clothes on, you would think nothing about going into that pond to save this little drowning child, even if it meant you had to send your clothes to the dry cleaners and maybe replace your leather shoes or something like that.

You, you would, you know, most people would say it would be monstrous to, you know, to prioritize your, you know, your work schedule, uh, and you need to punch, your need to punch the clock and your dry cleaning bill, um, to prioritize that over saving a life. You see this child, um, flailing around and all of the cues there are to tell you that there’s this, uh, helpless, blameless little creature with a real problem. It’s completely uncontroversial to imagine we run into that pond to save the drowning kid. What Singer does in this essay, uh, Poverty, Affluence and Morality is to say fine, okay, if that’s your intuition, then what’s your intuition with regard to sending money to an organization and a cost-effective organization, that’s going to make meals available in Sub-Saharan Africa?

It’s the identical ethical structure as the, the, the kid in the pond, um, except at this point, you don’t know anybody involved, you don’t, you don’t know the people who would be helped by your $50 a month. So when I teach this in, in my classes with my undergraduates, they start to come up with reasons why they’re not blameworthy if they were to do that. You know, they all say they would be morally blameworthy if they don’t pull the drowning kid out of the pond. But I ask, would you be morally blameworthy if you didn’t, you know, write that check once a month or, um, you know, set up that recurring credit card payment once a month? They come up with all sorts of reasons why they would not be morally blameworthy.

They say things like, I’m not sure the organization is going to be cost-effective. And then you can say, well, assume, assume it is, assume it’s really cost-effective. Or there’s so many other positive things I could be doing with it here at home, you know, in the United States, or I, I’ve, you know, I’m all budgeted out. I’m, I’m using, I’m taking care of my grandmother, you know, or something like that. They can come up with a lot of reasons where suddenly, even though it’s ethically equivalent, for some reason, there are these outside considerations that make them, make excuses seem defensible.

If you follow this argument out, though, what Singer concludes and it’s kind of Singer’s principle, I guess, is if you can create a good in the world that reduces suffering without inordinately increasing suffering for yourself, then morally you ought to do it. So, because he’s this, he is a utilitarian, for him the ethical coin of the realm is suffering. So I don’t know how many times this essay has been cited among scholars. I mean, I would assume it’s like 10,000 times or something like that. I mean, it’s just, it’s so influential. Uh, and this is really just one of several essays and books that are coming out at this point, um, that are about global poverty.

So in the 1970s, we see kind of culture-wide, and in fact, through most of the developed world, an intensification of interest in global poverty. The developed world starts to get very serious about global poverty, in part through arguments like Singer’s, in part, um, through simply the recognition that it’s, it’s good realpolitik to be concerned about making the world a more stable place. Um, we strengthen the United Nations with all kinds of capacities for stimulating development and, um, making more effective humanitarian interventions in the developed world. I think this is the beginning of a real renaissance or a real kind of new high watermark in our concern for strangers. We’re getting, we begin to get really good at helping the nameless, faceless others in, you know, literally on the other side of the planet.

So then how do you explain the kindness of strangers?
Michael McCullough:
You know, I’m an evolutionary psychologist, so I’m always trying to figure out, well, we thought it through somehow, you know, everything we do is generated by cognitive mechanisms, so like what’s the nature of the cognition that we’ve brought to bear on these problems? And I actually think this is a set of general-purpose kind of cognitive tools that we use. One is simply that we have a capacity for reasoning. And the second is we have a capacity for tracing our incentives and figuring out what’s good for us. I actually think the long arc of the history of human generosity is one about us encountering problems, large-scale, society-wide problems that involve mass suffering, looking at these as things that need to be explained, they need explanations. They kind of are offensive to how, to our worldviews.

So then we say, well, what are the, what are the problems? Why is this a problem? And then we can identify, well, it’s bad for business. It’s demoralizing, it’s offensive to God. So then people, what do people do? Well, they do the same kinds of argumentation and reasoning that they’ve always brought to solving corporate problems. And I think we do have evolved psychological mechanisms to promote argument.

So we argue about, you know, why do we not want vast swaths of humanity showing up sick and starving at the city gates? Well, we have all of these reasons why it’s, you know, it’s, it’s a bad idea. And then we say, well, what can we do? You know, what are the best approaches? So we get more and more sophisticated through history. Um, we can know more about what works. We can know more about the problems, we can know more about what works.

We get ethically smarter. We get ethically cleverer, I think smarter, I would say. Um, we have ethical tools that we didn’t have, um, 2,500 years ago. We have trade, technology, science, social science, the kind of science that can give us vaccines and pesticides and, um, high yield, um, cereals. We have wonderful intellectual and material resources at our disposal to make people better off in a way that we just couldn’t have done 2000 years ago, because we didn’t know how to do it. We didn’t necessarily have the ethical apparatus that convinced us that we should do it. And, um, we didn’t have the material resources that made it possible to do it.

Um, so why do you care about this?
Michael McCullough:
Um, I, I … (laughs) Why do I care about it? Um, I began caring about it merely as a sort of, um, insider social science matter because I thought we were not doing ourselves any favors as a, as a science by sort of very neatly saying like, oh, this is about reciprocal altruism, or this is about, you know, uh, kin altruism. Those were kind of some of the tools that evolutionary scientists wanted to use to explain this. And this just to me, did not look right. It did not seem to fit the facts of history. So as a kind of insider, inside baseball shop talk kind of thing, I wanted to present a different view, but the more I read and the more I wrote and the more I thought about it, the more I realized like this is, this is good news.

You know, it’s, uh, you know, I wanted to be, uh, a cheerleader for ethical progress in a time when we tend to be quite gloomy about progress and science, and we’re sort of disaffected and seemed to be going through some kind of malaise about, you know, whether we are better off as a society than we used to be. The more I read, the more convinced I became that we are doing better. You know, we are a better civilization, morally, technologically, et cetera. We are better than we were 2000 years ago. So I think I wanted to kind of tell a story of good news that I’d hoped would not only give people some hope, but also show them what are the raw materials at our disposal for pushing this forward into the future.

[music: Blue Dot Sessions, Silk and Silver]

Christiane: If you want to know more about The Kindness of Strangers or Michael McCullough’s other work, check out our show notes page at examiningethics.org.

The Prindle Institute for Ethics also produces a podcast called Getting Ethics to Work. You can find it at prindleinstitute.org/getethicstowork or wherever you find your podcasts.

Examining Ethics is hosted by The Janet Prindle Institute for Ethics at DePauw University. Christiane Wisehart wrote and produced the show, with editorial assistance from Hilary Koch. Our logo was created by Evie Brosius. Our music is by Blue Dot Sessions and can be found online at sessions.blue. Examining Ethics is made possible by the generous support of DePauw Alumni, friends of the Prindle Institute, and you the listeners. Thank you for your support.

The views expressed here are the opinions of the individual speakers alone. They do not represent the position of DePauw University or the Prindle Institute for Ethics.

[music fades]

View All Episodes

Visit Us.


2961 W County Road 225 S
Greencastle, IN 46135
P: (765) 658-4075



Monday - Friday: 8:00AM - 5:00PM
Saturday-Sunday: closed