Tragedy of the Commons Game
By Marissa T. Isaak, Graduate Student, UA School of Geography and Development, and Frank Van Weert, U.N. International Groundwater Resources Assessment Centre (IGRAC)
“Uncharacteristically cooperative” was how Frank Van Weert described the 14 students who attended the “Tragedy of the Commons” simulation that took place at the Water Resources Research Center on Oct 31, 2011. The purpose of the simulation was to allow students to learn from one another how to manage a common pool resource, in this case, an area of shared groundwater. “Tragedy of the Commons,” first articulated by Garret Hardin in 1968, is the idea that when commonly shared resources are used by a group of profit-maximizing individuals, the common resource will be destroyed or depleted by over-use. This depletion is not good for any of the users, but will happen because of inherent competition between the users. The idea is often mobilized by those who advocate for the privatization a public good, under the argument that in a privatization regime, motivations will align with protection of the resource for its long-term viability.
In the simulation Van Weert divided the students in 10 “families” wherein each one had to make a decision about how much land, out of a possible 100 hectares (247 acres), to bring under production in a fictional agricultural community. More land would mean more revenue generated. However, if each family produced their full 100 hectares, they would collectively draw down the groundwater so as to starve the nearby lake of the necessary water levels. In this case, there would be no fish for the families and each would have to pay a health cost of nutrition deficiency. Moreover, if the groundwater table dropped, then the families would have to pay additional pumping costs, eating up their earned revenue. A few additional features entered the game: Students could agree to an enforceable rule regarding how much land to bring under production, but the rulemaking would be accompanied by a transaction cost and only becomes effective when supported by a majority. Also family teams individually could decide to invest in water-saving technologies for their farms, such as drip irrigation, which would allow them to farm more with less groundwater drawdown. Finally, there were some unexpected events that could impact the farmers, such as climatic changes and pest invasions. With all this information, the 10 families began to farm.
In the first round, most farmers attempted rather aggressive farming, most choosing either 100 hectares or close to that much. This resulted in considerable drawdown of the lake and no fish for any of the community members. The group discussed the matter after the round and, finding this an unsatisfactory outcome, encouraged one another to farm fewer acres. In the subsequent rounds, pressure from the group pushed most of the farmers to both invest in water-saving technologies at considerable cost and to farm significantly fewer hectares.
There were, however, some outlier farms. One farm chose to continue to free-ride off the generosity of others - he continued to farm near his maximum 100 hectares despite the public pressure. This particular farm’s groundwater never dropped too low because the surrounding farms voluntarily agreed to reduce their amount of production. Another farm chose to bring only the minimal number of hectares under production, oftentimes failing to turn a profit. On this farm, the rationale was that they did not choose to profit-maximize like the others, and instead chose to work less so as to devote time to other leisure time pursuits. Despite these outliers, most of the farms voluntarily agreed to the reduction in land production in order to ensure the health of the lake and all the people within the community.
Van Weert was impressed with the students’ ability to discuss their situation and cooperate without implementing any sort of formal rule. He told the group that in the 12 times that he has run the simulation, it has never been so amicable. Usually he sees much more free-riding and competition between the farms. Was all this harmonious behavior the result of good training and awareness-building on water resources scarcity at the University of Arizona? Or did it have something to do with the friendly interaction of the students who hailed from Geography, Hydrology, Law, Political Science and SWES?
Van Weert questions whether the students would play as cooperatively when the stakes would be higher for them. Often in game theoretic experiments the players are being paid. What if, for example, the 5 lowest ranking students (in terms of accumulated capital in the game simulations) would need to pay a fee to the 5 highest ranking students. Or what if the game would be part of an official exam and the students would only pass when they accumulate a certain threshold value of capital in the game.
The game successfully illustrated some of the tradeoffs in a classic “Tragedy of the Commons” situation. But at times, the students had to suspend their true understanding of ecology in order to play the game. This simulation represented an over-simplified version of reality. For example, between simulations, the lake supposedly returned to total health. In the real world, if farmers were to draw down the groundwater in an area so as to decimate a nearby lake, it might not be revivable without considerable cost. Also, the simulation implied that all farmers lived equally with one another. In the real world, there are considerable differences between neighbor farms’ land entitlements, ability to invest in technology and their relative socio-political capital to influence decisionmaking.
Despite the simplified aspects of the game, the simulation gave students a taste of some of the real world decisionmaking calculations that irrigators must entertain as they manage their land both for profit and for protection of a common resource.