Game theory has proved itself countless times over as a powerful means for achieving success—from winning military battles to staging political campaigns. Until now, though, no one had applied it to the challenges of parenting. So Raeburn, an award-winning science writer and parent, and Zollman, a game theorist, set out to explore what would happen if you applied classic strategies from game theory to everyday negotiations with your kids. As they explained to Scientific American MIND senior editor, Kristin Ozelli, “We thought that something that has worked so well in so many human relationships and business dealings should work well with children. And we’ve shown that it does work well, and it can help solve many parenting problems.”

[An edited transcript of the interview follows.]

How many of your own children were involved in testing the ideas in this book?
Raeburn and Zollman: Paul has three grown children, whom he somehow managed to raise without using game theory. In the end, they all turned out to be wonderful adults, despite Paul’s stumbling but well-intentioned efforts. He also has two young children with whom he’s tried many of the ideas in The Game Theorist’s Guide to Parenting, with considerable success.

Here’s the trick: It’s essential to be consistent and to jump all the way in. Trying to solve parenting problems with a dash of game theory, a dollop of psychology and a neighbor’s over-the-fence observation won’t work. Stick with game theory, which is proved to work.

Kevin doesn’t have children, so we tested some of our advice with him. Paul is happy to report that Kevin behaved properly most of the time.

You describe several types of auctions in the book. Why is an auction fairer than flipping a coin?
Flipping a coin to settle a dispute seems fair to many of us because it gives each party an equal chance to get what she wants. Yet equal chances might not always be fair. Suppose that it's a Friday night and both Tori and Donny want to use the family car to hang out with different groups of friends. (They certainly aren't going to hang out together.) Who gets the car, and who's getting stuck with a bus pass?

You could flip a coin. That would be fine if Donny and Tori both have equally exciting (or equally dull) nights planned. But what if Tori finally got the courage to ask out her crush and Donny is only going sit around and watch TV? If you give Donny the car, he'll have fun, no doubt, but Tori will be devastated. On the other hand if you give Tori the car, Donny will be a little grumpy but he'll get over it.

In the book, we recommend you use a “chore auction” to solve problems such as Tori v. Donny. A chore auction is like a regular auction, except the kids “pay” by doing chores. Tori might be willing to clean the whole house in order to use the car for her date whereas Donny would be willing to do only a few dishes. This ensures that the child who wants the car more will get it—fair and “profitable”!

Why isn’t “rock, paper, scissors” a good method for deciding who wins a family argument—say, where to go for dinner or what movie to watch?
Finger-pointing games such as rock, paper, scissors have been used to settle disputes for millennia. It takes some real gall to argue against that much history, but we'll do it anyway. Game theory endorses the common sense way of playing this game: choose from among your three options at random. When you and your opponent both take this tactic, rock, paper, scissors works like flipping a coin; both players get an equal chance to win. As we've already mentioned, flipping a coin has its problems. But there's another wrinkle: it's surprisingly hard to actually choose each option with equal probability. We humans are terrible at being actually random! We tend to get in our own way. Consciously or unconsciously you say to yourself, “last time I played rock, so I'd better play paper or scissors this time.” That means we don't actually choose randomly, we tend to alternate too much.

Because of this, if you want to beat someone at rock, paper, scissors (maybe your kids?), you should agree to play best two out of three. Play rock on the first round and then play what would have lost to your opponent on the last round. (If they played rock last time, you should play scissors next time.) You'll win a surprising amount of time!

The strategies you describe all hinge on different flavors of fair. At what age do kids really get the idea of fairness? At what age will game theory start to work as a parenting tool?
Most of what we prescribe should work by the time children are five or six years old. That’s when they become exquisitely aware, for example, of any unfair division of Skittles. If your daughter gets a bigger handful than your son, he will let you know in the most insistent way that the division“wasn’t fair!”But he won’t be concerned at all if he got the bigger handful. Then the refrain becomes, “So I got more—tough noogies!”

By age seven or eight, however, kids become aware of unfair splits in their favor, and they become uncomfortable. Playing a move or two ahead, like a beginning chess student, they might realize that if they grab the bigger share now, they are likely to get no cooperation—and the smaller share—the next time. Siblings who think they’ve been cheated are not inclined to let it happen a second time.

Tell me about the “rotten-kid theorem.”
The economist Gary Becker surprised the world by proposing that even completely selfish (“rotten”) kids should act to help out their parents. Becker offered a very compelling mathematical argument in favor of this counterintuitive conclusion. Scholars were astonished, because it seemed to say that there wouldn't be conflicts within the family—at least not economic ones. Becker's mathematical argument was given the name “the rotten-kid theorem.”

Parents reading this are probably already snorting with derision, “If game theory says I won't have conflict with my kids, so much the worse for game theory.” Thankfully, game theorists are way ahead of you. Although the mathematical argument isn't wrong, per se, it relies on a number of assumptions that probably aren't true in real-life families. Ted Bergstrom, a game theorist at the University of [California,] Santa Barbara, developed more sophisticated models of the family and confirmed that conflict can often arise between parents and children.

In our book we go through a number of sources of this conflict and how game theorists suggest approaching them.

Why is this more likely to succeed in gaining your kids’ cooperation than standard parental manipulation or authoritative dictates?
Parents quickly learn that “because I said so” rarely succeeds. For better or worse, kids are their own human beings who control what they do. Whether you threaten them, bribe them or cajole them, you have to find a way to get your kids to choose the right thing.

Game theory says that if you want someone to behave differently, you have to change their incentives. This can be achieved through threats of punishment and promises of rewards. In the book we discuss some reasons why reward might work better than punishment but you will probably end up using both as parents.

Another way to alter a child's incentives is to help her understand the consequences of her actions better; help her to see why it is really in her interest to do what you ask. Kids often don't think about the long term in the same way that we do. (We adults have trouble with this sometimes, too.) We suggest a number of strategies from psychology and behavioral economics that can help kids to think more long-term.

What do you think may be the most useful—or widely applicable—single insight for moms and dads in practice?
We start the book with a very famous game theory example called the “cake-cutting problem”. Scholars use cutting up a cake as an analogy for distributing any number of resources, whether they are cookies divided between two kids, assets allocated to divorcing spouses or territory split among warring countries. One of the central insights in game theory is that you should try and strive for a way of cutting the cake that is envy free, where no child envies the piece the other child has. This forestalls the all-too-familiar cry, “That’s not faaaiiiirr!”

It's easier to get envy-free distributions when you find ways to let your kids divide among themselves. Game theorists have proved that the old standby, “I cut and you choose,” will guarantee good outcomes when there are only two kids. Also, if your kids need to think about what the other likes, outcomes will improve by letting them divide the cake themselves.

We show how these strategies can be put to work to divide not only cake but toys, books and time on a coveted device.

And if game theory fails?
We’re promising that it won’t! Alas, however, game theory will not make us perfect parents. We can show you decades of science demonstrating why parents must be consistent in their dealings with their children. Set limits and stick to them. But some nights even the most adept game-theorist parent is going to say, “Sure, you can have an extra half hour with Nintendo. Just give me some time to clean up the kitchen before I collapse!”

But look—if game theory eases arguments, keeps you and the kids happier and helps divide the Skittles, then you’ve made progress. If you can’t manage to follow every suggestion we’ve made, we’ll give you a break.

Oh, and can you pass the Skittles?


Read an excerpt from Raeburn and Zollman’s book, The Game Theorist's Guide to Parenting.

The Game Theorist's Guide to Parenting: How the Science of Strategic Thinking Can Help You Deal with the Toughest Negotiators You Know—Your Kids. Paul Raeburn and Kevin Zollman. Scientific American/Farrar, Straus and Giroux, 2016.