In nature, animals roar and bare their teeth to intimidate adversaries — but one side usually backs down, and real fights are rare. The wisdom of evolution is that the risk of violence is just too great.

Which might make one wonder: if war is so destructive, why does it happen? The question may sound naïve, but in fact it represents a deep puzzle. If a war will cost trillions and kill tens of thousands, it should be easy for either side to make a peace offer that both they and their opponents prefer to actually fighting it out.

The conundrum of how humans can engage in incredibly costly and protracted conflicts has occupied academics across the social sciences for years. In today’s episode, we speak with economist Chris Blattman about his new book, Why We Fight: The Roots of War and the Paths to Peace, which summarises what they think they’ve learned.

Chris’s first point is that while organised violence may feel like it’s all around us, it’s actually very rare in humans, just as it is with other animals. Across the world, hundreds of groups dislike one another — but knowing the cost of war, they prefer to simply loathe one another in peace.

In order to understand what’s wrong with a sick patient, a doctor needs to know what a healthy person looks like. And to understand war, social scientists need to study all the wars that could have happened but didn’t — so they can see what a healthy society looks like and what’s missing in the places where war does take hold.

Chris argues that social scientists have generated five cogent models of when war can be ‘rational’ for both sides of a conflict:

  1. Unchecked interests — such as national leaders who bear few of the costs of launching a war.
  2. Intangible incentives — such as an intrinsic desire for revenge.
  3. Uncertainty — such as both sides underestimating each other’s resolve to fight.
  4. Commitment problems — such as the inability to credibly promise not to use your growing military might to attack others in future.
  5. Misperceptions — such as our inability to see the world through other people’s eyes.

In today’s interview, we walk through how each of the five explanations work and what specific wars or actions they might explain.

In the process, Chris outlines how many of the most popular explanations for interstate war are wildly overused (e.g. leaders who are unhinged or male) or misguided from the outset (e.g. resource scarcity).

The interview also covers:

  • What Chris and Rob got wrong about the war in Ukraine
  • What causes might not fit into these five categories
  • The role of people’s choice to escalate or deescalate a conflict
  • How great power wars or nuclear wars are different, and what can be done to prevent them
  • How much representative government helps to prevent war
  • And much more

Get this episode by subscribing to our podcast on the world’s most pressing problems and how to solve them: type ‘80,000 Hours’ into your podcasting app. Or read the transcript below.

Producer: Keiran Harris
Audio mastering: Ben Cordell
Transcriptions: Katy Moore


The analogy between war and human health

Chris Blattman: So I think of it in a couple ways. One is that we all know that most people are healthy, and we would want doctors to get trained in the healthy functioning of the human body, and by virtue of being surrounded by sick people all the time, not forget that healthy people exist. And unfortunately we’re in a world of war doctors, right? People are trying to figure out and operate in these conflicts, and somehow forget that there’s this normal healthy state, and that’s the default and that actually the disease is rare. So that’s a first mistake we have to get past — that many do, but not all.

Chris Blattman: But then once we’re there, the funny thing about a lot of violence reduction — I see this in the city of Chicago, I see this in west African civil wars — there’s often a whole bunch of one-size-fits-all solutions, right? “Oh, this city used violence interrupters, so we must need violence interrupters.” Or, “This study used this new hot spots policing, or focused deterrence, or some policing tactic, and that worked there, so we need to import that.” You see that a lot in new cities.

Chris Blattman: The other thing you see is there’s a package: there’s this humanitarian peacekeeping complex in Africa that says, “First we need mediators. Then we need a demobilization and disarmament and reintegration program, DDR. Now we need a peacekeeping mission. Now we need a truth and reconciliation commission. And now we need elections within two years of the conflict.” There’s like this package, and you’re going to get it whether you like it or not.

Chris Blattman: If our doctor did that, if we just showed up at the doctor and said, “I’m kind of sick,” and he’s like, “You know what you need? Radiation therapy.” We’d be like, “Whoa, whoa, whoa. I didn’t even tell you what was wrong with me. You didn’t even spend any time thinking about it. What is going on? There’s this thing called diagnosis.” But of course it happens, because how do you solve the disease if you don’t have the diagnosis? And somehow we forget that. We just think, “Oh, it’s all violence. We need this again, just like South Africa had a truth and reconciliation commission. We need a truth and reconciliation commission.” It’s bonkers, but it’s super common.

Rob Wiblin: I think another analogy to health that I find that I have to constantly remind myself not to miss, is that death is rarely caused by a single malady, a single problem. Someone who’s 85 dies of pneumonia nominally. But in fact, they’ve died of so many different things that weakened the system until it was at a point that a viral infection could actually kill them. And so it is with conflict situations, where there was the fight in the bar that started the war. But actually that’s just the last straw. And what’s really going on is, why was the patient so incredibly sick that that could spread?

Chris Blattman: Exactly. I think I used the example of the First World War in my book, where I talk about how most people think the assassination of Archduke Franz Ferdinand, plus the miscalculations of Europe’s mediocre leaders, slept-walked the whole continent and the world into war. And that’s true in the same sense that pneumonia killed an 85-year-old person. But the only reason that person was so vulnerable — and the only reason we’re so vulnerable to some wacky little idiosyncratic situation or leader miscalculation — was because all the fundamentals were so fragile. But those fundamentals are less apparent.

Overrated causes of violence

Chris Blattman: You talked about how I’m not talking about interpersonal violence — even though actually that’s my day job, a lot of it is actually studying and developing programs to counter interpersonal violence. I do think human emotions and passions in these hot, reactive moments that do explain a lot of violence are really central to understanding a lot of interpersonal violence. And not just that: my relationship with my nine-year-old son, and whether we argue with our boss or our wife or whatever is really important.

Chris Blattman: And I think it’s not that it’s irrelevant when it comes to big groups; I just think of all of our human errors and foibles and frailties, it’s probably the least of them. Because it gets mediated by big bureaucracies. It fades over time. Maybe some monarch getting angry in July or August 1914 helped contribute to World War I. But by 1917, presumably hotheaded reactive violence and passions were not what was going on. So that’s a good example of one that I think is maybe overstated. We tend to take our interpersonal violence and then we project that onto nations, and I don’t think that’s a good guide.


Chris Blattman: So I think scarce water, any scarce resource, is something which we’re going to compete over. If there’s a little bit, we’ll compete over it. If there’s a lot of it, we’ll still probably find a way to compete over it. And the competition is still going to be costly. So we’re always going to strenuously compete. It’ll be hostile, it’ll be bitter, but it shouldn’t be violent. And the fact that water becomes more scarce — like any resource that becomes more scarce — doesn’t take away from the fact that it’s still costly to fight over it. There’s always room for that deal. The fact that our water is shrinking in some places, we have to be skeptical. So what is actually causing this? And then empirically, I think when people take a good look at this and they actually look at all these counterfactual cases where there’s water and war didn’t break out, we just don’t see that water scarcity is a persistent driver of war.

Chris Blattman: The same is a little bit true of climate change. The theory is sort of the same. How things getting hotter or colder affects interpersonal violence is pretty clear, but why it should affect sustained yearslong warfare is far less clear. That said, unlike water wars, the empirical evidence is a little bit stronger that something’s going on. But to me, it’s just then a bit of a puzzle that still needs to be sorted out. Because once again, the fact that we’re getting jostled by unexpected temperature shocks, unexpected weather events, it’s not clear why that should lead to sustained political competition through violence, rather than finding some bargain solution.


Chris Blattman: So there’s this instinct that we see: men are obviously more aggressive in interpersonal violence. Most of the soldiers are men. Most of the war leaders and generals are men. So it’s totally natural to try to extrapolate from individual aggression to group aggression. But it’s like the passions: I think aggression is just one of these emotions that gets filtered out in larger groups over long periods of time in long fights. So it’s not surprising to me that when people actually compare the likelihood of going to war with male or female leaders, that they’re just as likely to go to war with one another. And when people have found clever natural experiments in current times or history — when it was quasi-randomly a woman leader or male leader — they too are not necessarily much more likely to go to violence, or go to war.

Chris Blattman: So that may not matter very much. Now, people could retort — and they should — to say, “Well, these are just women leaders. This is not actually an integrated government.” And maybe that would be different. We don’t really have 50%, or have women represented to their proportion of the population, almost anywhere in history. So it’s not a fair empirical comparison. But I think the theory is strong that we shouldn’t expect this individual aggression to become dominant.

Chris Blattman: I absolutely think that enfranchising women is going to make people more powerful. We talked about anything that causes war is going to be something that helps you overlook costs. One big category of that is if a leader is an autocrat. In the extreme, the leader as an autocrat bears very few of the costs. If an unchecked leader bears very few of those costs, why would they consider them in that calculation? They’re going to be far too ready to use violence. They may even have a private incentive, something that benefits them — not others, not their group — to go to war.

Chris Blattman: Now let’s think about a democratic leader where only half of the population gets to vote for them. Maybe it’s only men, which of course has been true in many times and places. Maybe it’s only one ethnic group or only one religious group. Well, half of that population is going to be ignored — their interests, the costs of war that they bear is going to be ignored. And so the leader is going to be far too ready to use violence and far more vulnerable to other failures and breakdowns that lead the group into war. So anything that makes them more accountable to a wider swath of the people — including women, irrespective of whether they are more or less likely to support violence in surveys or something — is just going to make the world more peaceful. So that’s the first-order thing we should be thinking about.

The five causes of war

Unchecked interests

Chris Blattman: Think of an autocrat — think of a Putin, for example. If the main thing that is keeping us from going to war are the costs of war, and the person who makes that decision — in this case, a personalized autocrat — doesn’t have to bear the costs of everyday soldiering and death or deprivations from sanctions. Some of them — he’s bearing a lot of pain, let’s make no mistake, and risk — but doesn’t consider all of them. Well, that’s going to really reduce the incentives for peace and make him ready to use violence.

Chris Blattman: And what’s worse is when the circumstances around war give those leaders a private incentive: something that benefits them to go to war, but not their group. In Liberia, certain natural resources — not water, but diamonds, also timber, a few other goods that could be exported in this war economy — give warlords an incentive to go to war and stay at war, because they can use that disorder to enrich themselves. That’s a classic example. While that could be going on in a place like Russia, I think it’s more likely that there’s some reason for invading Ukraine, for example, that gives a private incentive. It may be a belief that this will entrench their power and solidify their political control, and continue to leave them unchecked.


Intangible incentives

Chris Blattman: Maybe the more important one for understanding a lot of conflicts — especially a lot of contemporary conflicts — which is also an intangible incentive, is that there’s some ideal that we hold that we refuse to compromise on. So the Ukrainians refuse to compromise on their liberty. The American revolutionaries refused to compromise on their liberty. And the Taliban refused to compromise, not so much on their liberty, but on a set of principles. The American administration, when dealing with the Taliban, refused to compromise on a certain set of principles of justice and of punishment of a grave crime.

Chris Blattman: And so our intransigence on a principle is a kind of intangible incentive that essentially says, “There’s a bargain to be made that we should accept” — semi-sovereignty as an American revolutionary or as a Ukrainian — “because they’re strong and we are weak. And I refuse.” That is the sensible compromise: “War will be costly, but because I value this ethereal thing so greatly, I will fight for it and I will not regret it afterwards. It’s not a mistake.” The principle of glory.



Chris Blattman: So uncertainty isn’t an inevitable path to fighting. But what happens in this situation is you’re like, “Wait a second, are they really as strong as they’re telling me? They ran those military parades, they did those border skirmishes, they have these big public investments in art — all these things that they’re signaling to me, is that a bluff?” It’s a little bit like poker. And in that circumstance, you can’t really verify amidst this uncertainty. So just like in poker, when you’re not sure what hand your opponent holds, you might fold and you might decide sometimes it’s worth it to call — or escalate, then call.

Chris Blattman: The same is true in warfare: sometimes it makes sense to escalate and call amidst this uncertainty. And in fact it makes sense to be somewhat unpredictable in that — just like you’re unpredictable in your bluffing and you’re unpredictable in your folding and calling. So it creates an environment where it’s in your strategic interest to sometimes fight.


Commitment problems

Chris Blattman: As soon as you hear “closing window of opportunity,” it’s your signal for a potential commitment problem. What was going on briefly in World War I was Germany’s fear that Russia would soon rise to be so powerful that they would be at a complete strategic disadvantage. And there was an opportunity to prevent that from happening, and that window of opportunity was closing very soon — it was probably going to close by 1917 or 1918, according to some of the German generals who were arguing this.

Chris Blattman: And the historians who don’t buy this fully are totally right to say, “Well, there’s ways to get out of that; it wasn’t a total commitment problem.” That’s why I sort of buy both stories. It was mostly a commitment problem. It was really hard to find a deal that Russia would be able to commit not to overpower Germany in the future and assure Germany of some stability. But it was really hard. And that’s the point at which our unchecked leaders and our misperceptions and our intangible incentives keep Europe from making a deal. And so we need both — it’s not one or the other.



Chris Blattman: A lot of the behavioral science and psychology and economics that people are so familiar with right now are actually about things that have to do with maximizing behavior, about optimizing a choice — not in a strategic interaction with somebody else, but just either with my future self or a mistake I make now in the moment, ignoring the actions of anybody else.

Chris Blattman: And a lot of those just aren’t that important, or just recede in importance in this particular kind of strategic interaction when the stakes are so high — because a lot of behavioral biases that we talk about go away when the stakes are super high. Not all of them, but many do. We have to focus on the limited number of ones that persist in big groups and bureaucracies that are working really hard to avoid a really, really bad outcome — and then can keep working three years into the whole mess. That’s what we need.

Great power wars

Chris Blattman: A lot of the things that occurred to me are questions of scale and difficulty of addressing in a short timeframe, rather than fundamental theoretical differences and what the diagnosis is. Partly because every war is its own little unique flower or snowflake, and so you have to diagnose each time.

Chris Blattman: I think if anything, there’s a common set of very difficult-to-resolve roots to great power wars. Which is that in a city, we can imagine a criminal superstructure organizing the gangs and being that third-party guarantor of peace and security and commitment, and punishing unchecked leaders and solving the five problems. And at a city or even a national level, states perform those functions pretty well. We’ve proven pretty good at constructing those institutions. And as an individual, if I decided I wanted to really make a contribution to those, I could probably make a difference on the margin.

Chris Blattman: On the other hand, it’s very hard for anybody, even the US president, to think, “How could we change the fundamental structure of the UN Security Council?” So there’s a scale of human institutions where we don’t yet have the solutions, and they’re so big and slow and subject to lots of forces and competing actors that they’re hard to manipulate. There’s this fundamental problem of anarchy, meaning there’s nobody above to settle these feuds and resolve these five problems, and there’s a difficulty of tackling that. We still have tools, but we just have to be willing to work on these low-return margins.


Chris Blattman: We talked about how it cuts both ways, but I do think that ideas of universal human rights and brotherhood and sisterhood is pacifying, in the sense that we have sympathy for others and so we’re less likely to go to war with them. I think the economic entanglements we have through trade are very protective. So I think untethering ourselves from the Chinese economy too much or too rapidly is not stabilizing, even if it achieves other national goals. That’s something Americans can vote on and decide on.

Chris Blattman: Entangling China in our lives as much as possible through immigration and trade and social exchange and watching their television shows and making sure they get some Netflix or something, are all going to, on the margin, I think help a bit. They’re not magic solutions, but that strikes me as very important.

Rob Wiblin: Entangling economies and cultures and people is one of the interventions that you talk about a bunch in the book. That’s one that I was very optimistic about, back in 2015. It seems it’s one where people have noticed that the entanglement maybe does make war less likely, but it also makes you vulnerable to the other side. It also potentially weakens your position against them, at least if you’re buying military equipment from them or something like that. There’s some that have a greater problem there than others.

Chris Blattman: Yeah. It’s complicated. There’s some countervailing effects. Like why is India not united with the West on this? Well, there’s lots of reasons, but one reason is they depend on Russian military equipment for their entire military apparatus, et cetera, et cetera. But I think on average, it’s pacifying. But people also have had a tendency to exaggerate this in history. There’s lots of Enlightenment thinkers saying, “Oh, the trade and liberty and human rights are going to extirpate war forever.” And that didn’t happen. But it’s not like an on/off switch. It can still be helpful.

Why undirected approaches won't work

Chris Blattman: Let me use an example from cities who want to reduce violence — say, intergroup violence between gangs, or interpersonal violence between individuals. In Chicago, they’re like, “We need to economically develop the South Side.” And I’ve been on radio programs in Chicago and people are saying, “Well, you’re doing this, but what we really need are jobs. Jobs, jobs, jobs, jobs, jobs.” And that doesn’t make sense to me for a few reasons.

Chris Blattman: Number one, for reasons we talked about earlier, making the pie larger or smaller doesn’t change the fundamental calculus. The fact that these gang members have jobs available might not change the fact that there’s whatever they’re fundamentally competing against. And we could debate that. What’s more important is just that it’s totally untargeted, right?

Chris Blattman: Chicago’s violence problem is 2,000 or 3,000 people. Any strategy directed towards 500,000 people — especially a job creation program that is probably never going to reach any of these extreme people — is a bad idea. What’s the analogy in the international arena? It’s any generic foreign aid that we give to poor countries that’s not actually specifically targeting the roots of violence and the diagnosis of what’s going on there, but it has this generic, poorly thought-through feel of, “Let’s just help Africa get richer and then there’ll be less war.” And it’s probably not true. It might be good to do that for other reasons, but it’s probably not going to reduce violence. You really have to be targeted. I think that’s the lesson from cities to nations: that you have to really think about who are the violent actors and decision-makers, and focus on them.

Rob Wiblin: Yeah, you have a section about how it seems like offering cognitive behavioral therapy to at-risk youth in that sort of context can significantly reduce the probability that they engage in murder, which is very cool. I was thinking in the great power context, can we pay Biden to go and get CBT therapy? Or how much would you have to pay Xi Jinping to go to a course? I actually think, even if you could do that, I’m not sure that it would help, because there’s the context where these decisions are not made in the heat of the moment in the same way that gang shootings are.

Chris Blattman: I think you’re right. I think a lot of CBT around violence is doing a few things. One of the things is that it’s trying to help you cope with that hot reactive violence, and that’s not the thing that we think is driving a lot of wars. Maybe personalized dictators. But the other thing it’s doing, is a lot of CBT — and this includes CBT like basic marriage counseling — [targets] all of these misperceptions; these availability bias; these projection bias; these hard, rigid, poisonous views that we have of our adversary; our tendency to interpret their actions in the worst light possible almost automatically without really having an ability to see it from their shoes or have any strategic empathy. Those are really, really, really common problems of interpersonal conflict as well, so it’s not just passions. So that is what CBT is really good at helping people get over.

What you can actually do to help

Chris Blattman: This is certainly a thing I grapple with myself. I guess I get up every day and work on this because I think it’s possible to chip away at the margin. And I wrote a whole chapter about that, because that’s the way I wanted to end the book in a concrete way. So rather than just have, “Everything’s getting better,” I was like, “OK, here’s how to operate better.”

Chris Blattman: One thing that I’m trying to do, but I think a lot of people can do, is I think it’s really important to change the conversation. I think it’s possible for individuals to shape how people think about and talk about conflict — and that can be in their city, very easily. That could be internationally. I do think a lone voice in Congress, even if it’s an aide who reminds people that this is costly and not the natural thing, or reminds people of some strategic dynamic or some psychological factor — or somebody who makes the State Department just be a little bit more accountable, a little bit more aware of biases — that would be a huge contribution.

Chris Blattman: I think individuals can do that kind of thing all the time. You can change conversations. And you can do that in any field: you can change the conversation in poverty alleviation, you can change the conversation in public health. It’s actually worrisome how easy it is to change the conversation, because I think it’s unsettled.

Chris Blattman: Then the question is, how do you get there? That’s the thing that happens in a lot of my office hours. People are like, “I want to do this. What are the concrete steps that I take?” Most people don’t really think about knocking on the doors that nobody else knocks on. If I wanted to actually change the conversation or change the mind of somebody, honestly, if I were 22 right now, I would just start emailing deputy ministers in 24 middle- and low-income countries where I could operate in the languages I know — just to be their aide, because they don’t have a lot of human capital and no nobody ever emails them. Everybody’s applying to whatever UN internship or something like that, but nobody’s reaching out to these people.

Chris Blattman: There’s dozens of cities on the planet where no one knocks on those doors, and I think you could make a real difference. If you’re a Western person, I think you’re just bringing a certain sort of style of thinking and a level of education, a level of human capital that is partly there, but not fully there. And that’s the theme through a lot of what I do. Why don’t I work in Russia? Everybody else is working in Russia. Nobody is figuring out organized crime in Colombia, as far as I can tell, so I’m going to work there. I’m going to be one of a very small group of people who are chipping away at these problems to change that conversation. And I think that’s been hugely effective.

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About the show

The 80,000 Hours Podcast features unusually in-depth conversations about the world's most pressing problems and how you can use your career to solve them. We invite guests pursuing a wide range of career paths — from academics and activists to entrepreneurs and policymakers — to analyse the case for and against working on different issues and which approaches are best for solving them.

The 80,000 Hours Podcast is produced and edited by Keiran Harris. Get in touch with feedback or guest suggestions by emailing [email protected].

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