Few lesson from A Common Dilemma

Few lessons from A Common Dilemma

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What can be better than learning about game theory through games? During my classes on this topic at the Wroclaw University of Economics, I regularly use A Common Dilemma. Why? It is a great game that presents basic mechanisms behind ‘the tragedy of the commons’. Here is how I use the game in a classroom.

I start the classes by explaining to the students the dilemma presented in the original paper by Hardin. Next, I show them some basic values of the production function. The purpose of this introduction is to give them a clear understanding of their situation, possible actions, and their outcomes, both on individual and group level. It is also necessary to tell them how much they can earn if they work together as a community.


When I’m quite certain they understand the rules we begin the game.

Thanks to the simple interface students can easily immerse themselves in the game.

I inform them that they can’t communicate during the exercise and we play five rounds. Then I pause the game and give them an opportunity to talk. I say that for 10 minutes they can discuss their outcomes. Usually, they use this time to complain about actions of others, but in the end, they always come up with some idea about how to act to earn the most as a community. After this discussion, they play 5 rounds without any communication. Then I pause game once again and tell them that for the last five rounds of the game they can communicate freely.

The most important element of the class is the discussion after the exercise. First, we talk about their results and how they differ from the optimal outcomes. Reports created by the platform come in handy to present their decisions and outcomes. Then we go on to the part where we want to summarize lessons learned from the game. During it I want my students to realize that:


  1. Communication is crucial in CPR dilemmas.

    Usually, after the first discussion most people follow the rules that they agreed on. In most cases, communication in the last 5 rounds of the game makes them perform better as a community.

  2. Trust can easily erode.

    In every game that even if most of the people followed the established rules there were some defectors. Their actions made other also resign from following the agreement. Even few of them can destroy the cooperation. Furthermore in some games erosion of trust was so intensive that students weren’t even interested in creating any more rules when it was possible.



    Harvest decision in A Common Dilemma
    Making decisions is always difficult, especially when the level of the trust between the members of the community is low.
  3. Sanctioning and monitoring are crucial to effectively manage CPRs.

    It is interesting that in discussion students usually forget about the latter element. They really want to punish ‘wrong-doers’, players who did not follow the established rules, but they tend to forget that then also need some kind of mechanism to check who belongs to this category.

Apart from that, the discussion brings out many interesting topics connected with the environment and how the ‘tragedy of the commons‘ apply to their everyday life.

All in all, I think that A Common Dilemma is a great game that can be used in the classroom. It’s quite simple and short – the whole exercise with introduction and discussion shouldn’t take longer than 90 minutes. Still, it engages students and gives them an opportunity to get down to the bottom of this dilemma.

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