tragedy of the commons.

Beyond making a somewhat cool song title, this is an interesting concept introduced in an influential article written by an ecologist named Garrett Hardin and first published in the journal Science in 1968. The article describes a dilemma in which multiple individuals acting independently in their own self-interest can ultimately destroy a shared limited resource even when it is clear that it is not in anyone's long-term interest for this to happen.

Central to Hardin's article is a metaphor of herders sharing a common parcel of land (the commons), on which they are all entitled to let their cows graze. In Hardin's view, it is in each herder's personal interest to put as many cows as possible onto the land in order to maximize their own profits, even if the commons are damaged as a result. The herder receives all of the benefits from the additional cows, while the damage to the commons is shared by the entire group. The catch is of course that if all herders make this individually (and therefore seemingly) rational decision, however, the commons are destroyed and all herders suffer.

At the beginning of his essay, Hardin draws attention to problems that cannot be solved by technical means (in other words, as distinct from those with solutions that require "a change only in the techniques of the natural sciences, demanding little or nothing in the way of change in human values or ideas of morality"). Hardin contends that this class of problems includes many of those raised by human population growth and the use of the Earth's natural resources. To make the case for "no technical solutions," Hardin notes the limits placed on the availability of energy (and material resources) on Earth, and also the consequences of these limits for "quality of life." To maximize population, one needs to minimize resources spent on anything other than simple survival, and vice versa. Consequently, he concludes that there is no foreseeable technical solution to increasing both human populations and their standard of living on a finite planet.

From this point, Hardin switches to non-technical management solutions to population and resource problems. As a means of illustrating these, he uses the hypothetical example of a pasture shared by local herders. The herders are assumed to wish to maximize their yield, and so will increase their herd size whenever possible. The utility of each additional animal has both a positive and negative component:

Positive: the herder receives all of the proceeds from each additional animal.
Negative: the pasture is slightly degraded by each additional animal.

The crucial piece here of course is the division of these costs and benefits is unequal: the individual herder gains all of the advantage, but the disadvantage is shared among all herders using the pasture. Consequently, for an individual herder the rational course of action is to continue to add additional animals to his or her herd. However, since all herders reach the same rational conclusion, overgrazing and degradation of the pasture is its long-term fate. Nonetheless, the rational response for an individual remains the same at every stage, since the gain is always greater to each herder than the individual share of the distributed cost.

Because this sequence of events follows predictably from the behaviour of the individuals concerned, Hardin describes it as a "tragedy." In the course of his essay, Hardin develops the theme, drawing in examples of latter day "commons," such as the atmosphere, oceans, rivers, wildlife, national parks and advertising. A major theme running throughout the essay is the growth of human populations, with the Earth's resources being a general commons.

In the context of avoiding over-exploitation of common resources, Hardin concludes by restating "liberty is the recognition of want." He suggests that "liberty" completes the tragedy of the commons. By recognizing resources as commons in the first place, and by recognizing that, as such, they require management, Hardin believes that humans "can preserve and nurture other and more precious freedoms." Aside from its subject matter (resource use), the essay is notable (at least in modern scientific circles) for explicitly dealing with issues of morality. In fact, the subtitle for the essay is "The population problem has no technical solution; it requires a fundamental extension in morality."

As a metaphor, the tragedy of the commons should not be taken too literally. The phrase is shorthand for a structural relationship and the consequences of that relationship, not a precise description of it. The "tragedy" should not be seen as tragic in the conventional sense, nor should it be taken as condemnation of the processes that are ascribed to it. Similarly, Hardin's use of "commons" has frequently been misunderstood, leading him to later say that he should have titled his work "The Tragedy of the Unregulated Commons."

As it relates to social evolution, a tragedy of the commons is brought about by selfish individuals whose genes for selfish behaviour come to predominate, so the metaphor cannot necessarily explain how altruism arises. This question is addressed instead by models of possible mechanisms that can give rise to "reciprocal altruism," leading to ideas like the quid pro quo rule of reciprocation (or the Brass Rule from an earlier – also quite lengthy – post). These models freed evolutionary theory from the limitations imposed by the concept of "inclusive fitness," a previous explanation for altruism, which proposed that organisms help others only to the extent that by doing so they increase the probability of passing shared genes to the next generation (as it turns out, we help one another because it makes us feel good).

The commons is a specific class of social dilemma in which people's short-term selfish interests are at odds with long-term group interests and the common good. In academia, a range of related terminology has also been used as a kind of shorthand for the theory behind it, including resource dilemma, "take-some" dilemma and common pool resource. Commons dilemma researchers have studied conditions under which groups and communities are likely to under- or over-harvest shared resources in both the lab and the field. Research programs have concentrated on a number of motivational, strategic and structural factors that might be conducive to commons management. And finally, in game theory, which constructs mathematical models for individuals' behavior in strategic situations (like the Prisoner's Dilemma), the corresponding "game," developed by Hardin himself, is known as the Commonize Costs — Privatize Profits Game (CC–PP game), which definitely does not have as good a ring to it as the aforementioned game.

Breaking this down some more, we can examine some of those factors that have been considered. First, when looking at motivational factors, research shows that some people are more motivated than others to manage the common resource responsibly. Using the commons dilemma game, researchers found that people with "prosocial" value orientations harvest less from a resource during a period of scarcity. These same individuals are also more inclined to engage in sustainable environmental behaviours such as taking public transport, conserving energy and water, and explaining their decisions in terms of environmental impact. Motivation to conserve a common resource is also promoted by people’s group ties – when people identify with their group, they are more likely to exercise personal restraint. Similarly, something that was noticed in the field was that strongly-knit communities are usually better at managing resource shortages than communities with weak social ties. Something else that was realized was that resource uncertainty seemed to further contribute to over-harvesting. In commons dilemmas, this tends to increase individual "harvesting" (of those resources) and expectations about how much other people harvest. When there is uncertainty, people overestimate the size of the resource and perceive greater variability in how much other people take.

Further studies looked at how real-world communities manage communal resources, such as fisheries, land irrigation systems and farmlands, and they identified a number of factors conducive to successful resource management. One factor is the resource itself – resources with definable boundaries like land can be preserved much more easily. A second factor is resource dependence – there must be a perceptible threat of resource depletion, and it must be difficult to find substitutes (um, think oil). The third is the presence of a community – small and stable populations with a thick social network and social norms promoting conservation seem to do better (think of native tribes or – on a larger scale – Europe, which does not suffer from suburbia and the disconnection that produces nearly to the extent as does the United States). A final condition is that there are appropriate community-based rules and procedures in place with built-in incentives for responsible use and punishments for overuse (do not think of the United States – at least not currently).

This seems all quite relevant today in the predicaments we find ourselves and those last results seem quite obvious. It is frustrating to hear about "tragedies" like that played out by AIG (where they are clearly not concerning themselves with the commons), and of course the many varied "tragedies" we have endowed upon ourselves when it comes to the environment. The question circles back to the studies already carried out and being undertaken that deal with how we can view the common thread that connects us all? Will we succeed or will we fail?

Regardless, it is inherently impossible that some of us will succeed while others fail; we will either – all as one common species – succeed or we will similarly all fail. I tend to hold onto my optimistic point that someway, somehow we will indeed find our way.