mean that hoping for spontaneous global action on climate change might be unrealistic. Arguably, some kind of rules and trust must be established to cooperate when incentives constantly lure people and states to follow their own self-interest … toward collective planetary ruin. In this chapter, we address this persistent and vexing problem: How, if at all, can rules and norms of global behavior be fashioned to encourage shared costs and collective benefits? At what scale is cooperation possible?
The Prisoner’s Dilemma
Such questions are of universal concern since problems of this sort are ubiquitous. There are countless examples from our own daily ecologies as well as those around the globe.
Neighbors, for example, need to pull weeds from their lawns to keep them from spreading across property lines. By failing to do so, any one non-cooperating neighbor enjoys some benefits from their neighbors’ sweaty work (fewer dandelions in their yard), but simultaneously provides an ongoing seed source for dandelions that might spread to the lawns of others.
It is tempting for someone to spill the small quantity of paint left over from renovating a bathroom into a storm drain rather than take the time to dispose of it legally at an approved dump site. Should a single household be the only one to behave in this way, it enjoys a lower labor burden and benefits from the healthy environment resulting from the majority of hard-working cooperative neighbors who do not dump paint into public waterways. But since such temptation exists to all, the incidence of paint dumping is far higher than anyone individually desires.
Nor is the situation of a homeowner in urban America or Europe entirely different from that of a villager in rural India. There, the benefits from a community forest include the ability to graze livestock in the shade of trees and the availability of seeds and pods that fall from trees, among other resources. These collectively enjoyed benefits are only available if the trees of the forest are not cut down for fuel or construction timber. It is inviting for any individual household to cut down a tree or two for their own purposes, making only an incremental change in the density and health of the village forest. As long as others refrain from doing the same, these minimal costs are spread across the village and the benefits to the household, which may need to go great distances to collect fuelwood otherwise, are obvious. But again, since the incentive to break the rules is shared by all, and in anticipation of the fact that others may well “cheat” and cut trees, householders might well be tempted to cut trees as soon and as quickly as they can, in an effort to gain resources before their neighbors do.
In all of these cases, cooperation is necessary for the best outcome, but an incentive exists to take a “free ride” and let others invest time or money or restrain their behavior while we do not. Since the incentive exists for everyone, the possibility of total failure always looms.
Prisoner’s Dilemma An allegorical description of a game-theoretical situation in which multiple individuals making decisions in pursuit of their own interests tend to create collective outcomes that are non-optimal for everyone
A popular metaphor for situations such as these is the story of the Prisoner’s Dilemma. In this tale, so often replayed on contemporary television crime dramas, you are asked to imagine two people charged with a crime, perhaps something like burglary, in which the best evidence that the police have (though not the only evidence) would be the testimony of one of the burglars against the other. Both suspects are taken into custody by the police and interrogated individually. Each is separately told that if they testify against the other person, they will go free or have a greatly reduced sentence. The logical decision in a perfect world is for both of the suspects to keep their mouths shut. With no one talking, they might each serve a short jail term, if any term at all. The problem stems from the fact that each knows that the other might well “rat” him out. If one chooses not to talk while the other “rats,” the reticent one will do hard time while the other one goes free. Since no one wants to be a “sucker” and suffer at the hands of the other, the predictable outcome is that both testify against the other, leading to the worst possible mutual outcome, one in which both do hard time. Trying to anticipate and avoid the punitive “defection” of the other person, the two partners act in service of the police. Such a situation not only invites each person to “rat” out the other, it actually makes it rational to do so, even though the outcome is inevitably bad for everyone, something no rational person would choose if they could control the behaviors of both parties.
Game Theory A form of applied mathematics used to model and predict people’s behavior in strategic situations where people’s choices are predicated on predicting the behavior of others
These sorts of fascinating dilemmas are the province of game theory, adopted by thinkers who employ a form of mathematical analysis of decision-making, examining those sorts of situations that might be expressed in game terms. For game theorists, certain games provide models for how people think and behave. Of most interest are games where the crux of the problem is anticipating what the other player might choose to do, where bluffing and second-guessing are paramount. Such is the case of our two prisoners, who individually reach what is ultimately a bad mutual decision because they are trying to anticipate what the other prisoner might decide to do. Along these lines, and as established by the refugee scientist John von Neumann after World War II, game theory understands a “game” to be “a conflict situation where one must make a choice knowing that others are making choices too, and the outcome of the conflict will be determined in a prescribed way by all the choices made” (Poundstone 1992, p. 6).
In game theory, as in the Prisoner’s Dilemma, the best outcomes are typically achieved by cooperating, while individual incentives tend to lead to a reason not to cooperate. The problem of our two suspects might be expressed in abstract terms by game theorists as in Figure 4.1. These games can be made ever more complicated by introducing quantitative cash rewards and punishments and making the decisions more complex, involving, for example, investment in a public good versus a private bank, and so on. Complex mathematics can be used to predict behaviors, including retaliations, mutual learning, and system collapse.
Figure 4.1 The Prisoner’s Dilemma in game-theoretical terms. The best outcome, in the upper left, is also the least likely, since each player prefers to avoid the worst individual outcomes, in the upper right and lower left corners, leading to the worst collective outcome, in the lower right.
The Tragedy of the Commons
The first applications of game theory mathematics were directed to the Cold War logic of mutual nuclear annihilation. Funded by the RAND Corporation and the US Pentagon in the 1950s, game theorists asked the unthinkable: Is it rational to strike first with nuclear weapons, not knowing whether and when the enemy might do so? Is it rational to drop the bomb?!
But what might any of this have to do with environment and society? Applying this kind of thinking to our interactions with the natural world leads to some potentially grim and tragic conclusions. For while there is a possibility of cooperation around environmental conservation, there is a potentially overriding incentive to “defect,” in the language of game theory, leading to a general inability to manage or control our consumption and use of the environment, and so to environmental destruction.
Thinking along these lines, Garrett Hardin presented one of the most compelling, persistent, and in some ways problematic arguments linking environment to society through the commons. In his article “The Tragedy of the Commons,” published in Science in 1968 (where von Neumann is prominently cited), he directed this logic to the problem of overpopulation. He argued that while the advantages for any individual
