Blizzards are a concrete example of what game theorists call the “drift problem,” a cousin of the Prisoner’s Dilemma that offers clues about why we choose to cooperate.
By Joseph Howlett edited by Clara Moskowitz
Kate Wieser/Getty Images
A blizzard is a true test of the social contract. Nature uniformly dumps 12 to 18 inches of nuisance throughout an entire community and leaves it to you and your neighbors to sort out the mess. Who cleans the streets or sidewalks? What about the “sneckdowns“?! Every storm leaves behind a maze of common responsibilities that we must resolve and not always without conflict.
Why and how social creatures like us choose to cooperate remains a largely open mystery. Game theorists, computer scientists, anthropologists, and behavioral economists have all approached the problem from different angles. There is even a scientific version of the blizzard riddle called the “drift problem.”
It is a variation of the prisoner’s dilemmawhere two accomplices in a theft are separated and asked to denounce each other. Everyone must decide whether to betray their partner to free themselves or to remain silent in the hope that both will escape. (If both swing, they both go to jail.) The snowdrift problem poses a related question: Who should shovel in a selfish world?
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Imagine waking up in the middle of a snowstorm and needing to get to work. You manage to dig out your car and drive halfway until a huge snowdrift blocks the road. There’s another car coming from the other direction that’s also stuck, and you both have a shovel.
Both drivers must choose whether to cooperate or not. The game awards points for each of four possible outcomes. You earn the most points if you can convince the other person to do all the work. The payment is moderate if both agree to shovel: everyone gets to work within a minimum of time. And even if your opponent chooses to stay warm in the car, it’s better to shovel. It’s not fair, but at least you’ll (eventually) get where you’re going.
Game theorists typically divide the decision into several rounds, as if the two drivers are renegotiating after a few minutes of shoveling. Compared to the apparent consequences of the Prisoner’s Dilemma, getting cheated in the Snowdrift Problem scenario is not as disastrous. (Any delay on work is worth years in prison.) But in both games, theorists say, it’s generally better to fool your opponent if you can. This result raises a question: why do humans cooperate as much as we do?
Studies show that the Blizzard version of the game leads to more cooperation than the prisoner’s dilemma. And many sociologists believe the former is a better indicator of real-world cooperative challenges, where betrayal often hurts oneself as well as others.
The snowdrift problem and its variants remain active areas of study. Recently, scientists have used graph theory to evaluate a new strategywhich they call “poor-defective-rich cooperation.” This roughly translates into the following advice: check to see if your neighbors are cooperating; if their walkways appear clear, then you should decide to participate in them as well.
Scientists turn to these very simplistic models because cooperation is a true wonder of the natural world. Natural selection seems to prescribe selfishness in most situations, and yet everywhere in the animal kingdom we see the fruits of collaboration. Games like the Snowdrift Problem are a way to explore this puzzle using simple mathematics, with the goal of understanding how a group of selfish individuals add up to form a cohesive society.
Now stop procrastinating and go shovel that walkway.
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