[This is an updated and modified version of a post originally sent to paid subscribers only.]
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I’m going to start this post with an example from the movie Carry-On. Don’t worry—it’s not a spoiler. It happens early in the movie, and it’s in the trailer.
Ethan Kopek (played by Taron Egerton) is working at a baggage-scanning lane at LAX airport. Someone hands him an earbud, and he gets a text telling him to put it in his ear. He is then in contact with a ruthless mercenary (played against type by Jason Bateman). Ethan is told that he has to let an associate of the mercenary get a carry-on case through the scanner. If he doesn’t, Ethan’s pregnant girlfriend, who also works at the airport, will be killed.
We learn two things right away. First, what’s in the case is deadly. Second, these men are violent criminals; we (and Ethan) watch as the mercenary murders a man in the airport to protect his plan. So when they say they can kill Nora whenever they want to, you know they mean business.
Here, watch the trailer:
What would you do in Ethan’s position? Let the bag go through? Or hit the alarm, stop the bag from getting onto a plane, and save countless lives—but be responsible for the murder of the person you love the most.
Ethan was under pressure, but you’re not. Take your time.
Ready? Here’s my answer.
He should stop the bag.
This way, he will save the lives of hundreds of people. And the good thing is that there’s no cost. Nora isn’t at risk. Once the bag has been stopped and the plot has been foiled, there is no point in killing her. Nothing would be gained, and even ruthless criminals don’t murder people for no reason. (Putting aside the moral issues around taking an innocent life, killing someone inside an airport carries a lot of risk for the killer.) The mercenary is making an empty threat.
I know it’s a movie, so to make it especially cool, Ethan can look resigned as the bag passes through the scanner so that we think the mercenary has succeeded, and then, at the last second, he hits the alarm and tackles the guy with the carry-on. Then he can shout: “That’ll teach you to make an empty threat!”. The movie would last about half an hour, which is unusual, but it would make people think, and isn’t that what really matters?
Great advice, right?
A typical threat has the form “Do A, or I’ll do B.” Certain conditions must be met for this to work.
The person making the threat must want A to happen, and the person being threatened must not be planning to do A otherwise. This is just common sense; why use a threat to get an outcome that you don’t want or that would happen regardless?
The threatened person would rather do A than experience B.
The person making the threat would rather do B than have A not be done.
Here’s a simple example from any action movie. A terrorist is running away, and our protagonist points her gun at him and shouts, “STOP, or I’ll SHOOT.” The following conditions are likely to hold.
The protagonist wants the terrorist to stop, and he wasn’t planning to do so otherwise.
The terrorist prefers stopping to getting shot.
The protagonist prefers shooting the terrorist to having him get away.
The third condition is the interesting one. Sometimes, the threatener doesn’t want to carry out the threat. Suppose the protagonist has sworn to herself that she will never shoot anyone again. If so, her threat is a bluff; it can only succeed if the terrorist doesn’t know her priorities.
A more everyday example: A father shouts at his children, “Stop fighting, or I’ll turn this car around!” But maybe the father also wants to go to Disney World, and suppose the children know this. Then it’s another empty threat.
The father example differs from the example above in one crucial regard, though. In the case of the running terrorist, it’s a one-shot interaction. They’re not going to do this over and over again. But the father has to live with his kids, and so he has an extra impetus to carry out his threat, even if it’s to his detriment in the short term—if he doesn’t, he might be ignored in the future. If his children know that he worries about this, they are more likely to take him seriously. (Interestingly, then, his threat carries more weight if his children see him as insecure in his authority—in this situation, his weakness is a strength.)
The interaction in Carry-On is clearly a one-shot deal. It’s not like the mercenary is returning to the airport each week with a different bag that he has to get past Kopek. So the mercenary won’t be compelled to kill Nora to convince Ethan to take him more seriously in the future.
Put yourself in the shoes of the Bateman character now. How can you convince Kopek that you’re not making an empty threat?
An excellent introduction to these issues can be found in a chapter of Steven Pinker’s How the Mind Works called “Hotheads.” (This is where, many years ago, I read about all of this for the first time.) Drawing upon the insights of the economist Thomas Schelling, Pinker begins with the classic example of a potentially empty threat—mutually assured destruction. Imagine that it’s 1962, you are the President of the US, and the Russians have just dropped an atomic bomb on New York.
In front of you is the phone to the Pentagon, the proverbial button, with which you can retaliate by bombing Moscow.
You are about to press the button. The nation's policy is to retaliate in kind against a nuclear attack. The policy was designed to deter attackers; if you don't follow through, the deterrent would have been a sham.
On the other hand, you are thinking, the damage has been done. Killing millions of Russians will not bring millions of dead Americans back to life. The bomb will add radioactive fallout to the atmosphere, harming your own citizens. And you will go down in history as one of the worst mass murderers of all time. Retaliation now would be sheer spite.
But then, it is precisely this line of thinking that emboldened the Soviets to attack. They knew that once the bomb fell you would have nothing to gain and much to lose by retaliating.
You’ve already messed up. It’s not rational to retaliate, and the Russians were smart enough to know this. They called your bluff.
What should you have done instead?
One solution that Schelling discusses is to set up a system that takes the decision out of your hands—a doomsday machine that will automatically retaliate—and, of course, ensure that the Russians are aware that such an irreversible device is in place. Pinker gives a couple of other examples along these lines:
A hijacker who threatens to blow up a plane if anyone tries to disarm him will have a better chance of seeing Cuba if he wears explosives that go off with the slightest jostling. A good way to win the teenagers' game of chicken, in which two cars approach each other at high speed and the first driver to swerve loses face, is to conspicuously remove your own steering wheel and throw it away.
A related option is to make your adversary believe that you yourself are a doomsday machine. You are crazy, vindictive, and irrational.1 Pinker quotes Schelling here:
If a man knocks at the back door and says that he will stab himself unless you give him $10, he is more likely to get the $10 if his eyes are bloodshot.
Richard Nixon was a believer in this tactic. Here is what he told his Chief of Staff during the height of the Vietnam War.
I call it the Madman Theory, Bob. I want the North Vietnamese to believe I've reached the point where I might do anything to stop the war. We'll just slip the word to them that, "for God's sake, you know Nixon is obsessed about communism. We can't restrain him when he's angry—and he has his hand on the nuclear button" and Ho Chi Minh himself will be in Paris in two days begging for peace.
So far, we’ve described the appearance of irrationality as a deliberate tactic. But, often, people really are irrational in precisely this way. One prominent theory of the evolution of emotions, such as anger, is that they serve to motivate an adaptive form of tactical irrationality.
You don’t have to think about nuclear war to see how this could work. If you are a rational Mr. Spock, I can exploit you in all sorts of ways, confident that any retaliation you carry out will be reasonable and proportional. But, if I know you have a temper and will respond disproportionately, I must treat you with more respect.2
Talk of strategic craziness leads us to Donald Trump. In Alchemy, Rory Sutherland talks about the election eight years ago between Hillary Clinton and Donald Trump and notes that Trump had one significant advantage as a leader:
Irrational people are much more powerful than rational people, because their threats are much more convincing. … Being slightly bonkers can be a good negotiating strategy; being rational means you are predictable, and being predictable makes you weak. Hilary thinks like an economist, while Donald is a game theorist …
I thought of this when Trump threatened to impose severe tariffs on imports, including from my home country of Canada. If Kamala Harris were president, this would be an empty threat; such tariffs were seen as harmful to the US economy, so no reasonable president would impose them. But Trump? People took this threat seriously—and they were justified in doing so.
Back to Carry-On.
ETHAN: You’re making an empty threat. Once I stop your guy, it’s all over. There’s no point in killing Nora. You know it, and I know it. So screw you.
But the mercenary has read his Schelling.
MERCENARY: Yeah, but here’s the thing, Ethan. Once my guy goes through and gets safely to the gate, he’s going to send a text to the man who is planning to shoot Nora. When the shooter gets the text, he’ll walk away, and Nora will live. But if twenty minutes go by and there’s no text, he will shoot Nora dead. And you know something, Ethan? I have no way of calling this off. So follow my instructions.
That’ll work. Or how about:
MERCENARY: You think you’re smarter than me, Ethan? Are you laughing at me, Ethan? I’ll show you what happens when people laugh at me. Just try it, Ethan. I’ll fucking show you.
That’ll work, too.
As Schelling was careful to note, he was not the first to discuss the power of seeming irrational to your enemies; see here for a discussion of others who had the view before him. In 1517, for instance, Machiavelli wrote that it is sometimes "a very wise thing to simulate madness."
There’s a balance here, though. I once had a colleague with a hair-trigger temper, hyper-sensitive to any slight. I treated her with excessive care and respect; she was a Doomsday Machine with tenure. But I also avoided interacting with her, as did most other people. There’s a delicate trade-off; you want to be taken seriously, but you also want to be amenable to compromise and forgiving about minor transgressions; otherwise, nobody will hang with you.
I remember reading that if you want to win a game of chicken with a bunch of cars while crossing a busy street, the best way to do it is to wear blindfolds and earmuffs. The cars know you won't jump out of the way so they'll be forced to swerve around you. I have never tried this personally, though.
Surely the threatening agent's intelligence, competence, and belief system have roles to play? Surely these are paths by which actual, not calculated, irrationality get in?