Guest essay by Eric Worrall
What would you think of a Psychology lecturer who every year plays a real life version Prisoner’s Dilemma with undergraduates, awarding course credits based on the outcome of a climate cooperation game?
What a Simple Psychological Test Reveals About Climate Change
If everyone’s success depended on it, would you share—or be selfish?
By Dylan Selterman
I teach undergraduate psychology courses at the University of Maryland, and my classes draw students with diverse interests. But every one of them perks up when I pose this question: Do you want two extra-credit points on your term paper, or six points?
I tell my students that the extra-credit offer is part of an exercise illustrating the interconnectedness of choices individuals make in communities. I explain that the exercise was inspired by an ecologist named Garrett Hardin and an address that he delivered 50 years ago this summer, describing what he called “the tragedy of the commons.” Hardin said that when many individuals act in their own self-interest without regard for society, the effects can be catastrophic. Hardin used the 19th-century convention of “the commons”—a cattle-grazing pasture that villagers shared—to warn against the overexploitation of communal resources.
A possible solution seems simple: If everyone just moderated their consumption, we’d have sustainability. As many of my students say, “If everyone chooses two points, we’ll all get the points.” And yet, for the first eight years I used this exercise, only one class—of the dozens I taught—stayed under the 10 percent threshold. All the other classes failed.
This exercise was developed more than 25 years ago. Professor Steve Drigotas of Johns Hopkins University had been using it for some time when he administered it to me and my classmates in 2005. My class failed too—and I, who had chosen two points, was incredibly frustrated with my peers who had chosen six.
In 2015 one of my students tweeted about the exercise—“WHAT KIND OF PROFESSOR DOES THIS”—and his lament went viral. People around the globe weighed in: Does so many people choosing six points mean it’s human nature to be greedy and selfish?
In 2016 I decided to change things up. In hopes of finding a way to increase cooperation, I drew from the scientific literature on social groups and introduced a third option: Students could choose two points, six points—or zero points. That’s right. Zero. Why would anyone do that? Well, for each student who chose zero points, one of the six-point choosers (selected randomly) would lose everything, reducing the total number of six-point choosers by one.
Prisoner’s dilemma is an interesting intellectual concept – unless you are one of the prisoners, or in this case students. In which case being one of the prisoners in a game of Prisoner’s Dilemma might be a nasty and humiliating experience, especially for a student who is struggling, a student who really needs those precious additional course credit points.
To be fair, in 2016 Lecturer Dylan Selterman improved the odds of at least some students winning additional class credits, by offering self sacrifice option, allowing students to deliberately choose zero class credits for themselves in return for pulling down one of their more ambitious fellows.