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The Tragedy of the Commons The tragedy of the commons refers to how free access and unrestricted demand for a finite resource ultimately structurally dooms the resource through over-exploitation. This occurs because the benefits of exploitation accrue to individuals or groups, each of whom is motivated to maximize use of the resource, while the costs of the exploitation are distributed among all those to whom the resource is available (which may be a wider class of individuals than that which is exploiting it). The concept was popularized by Garrett Hardin’s essay in 1968 called the “Tragedy of the Commons”; however, the concept has been around since the time of Aristotle who said “that which is common to the greatest number has the least care bestowed upon it”. In his essay, Hardin develops this theory with the use of a hypothetical common 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. Crucially, the division of these costs and benefits are 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 weighing these, the rational course of action is to add an extra animal, and another, and another. However, since all herders reach the same rational conclusion, overgrazing and degradation of the pasture is its long-term fate. Hardin draws links with this hypothetical situation to that of the Earth’s resources being a general commons, such as the atmosphere, oceans, rivers and fish stocks, which is being exploited by the ever increasing human population who are each individually seeking to maximize their gains. The Game: Concept: Students are introduced the idea of carrying capacity and the tragedy of the commons. In this simulation, students desiring to draw renewable resources from a common pool experience, by trial and error, how a shared resource can be depleted, and not all individuals benefit equally, and ways in which individuals can maximize their gains without depleting the common resources. Materials: Tokens (such as Popsicle sticks) – 10 per student Candies of other rewards Stopwatch or watch with a second hand CD or tape player CD of tape of lively music (at least 8 minutes worth) Procedure: Count out ten tokens for each student playing the game. Put one-fourth of them in a separate pile. Seat the students in a circle In the center of the circle, place the pile comprising one-fourth of all the chips (for example, if you have 4 students, you use 40 tokens, and begin with 10 in the center. If you have 10 students, you use 100 tokens and begin with 25, and so on). Read the following rules carefully to students. Allow time for questions and answers to make sure students understand the rules of the game thoroughly. Rules: 1. The tokens belong to all of you, to the group. 2. Music will be played, and while it is playing, each of you may take tokens out of the pool of tokens in the center. 3. You may no put tokens back into the pool once you have taken them out. 4. Each of you may trade in 10 chips for a piece of candy. 5. As soon as the music stops, I will double the number of tokens left in the pool at that time, and then continue the game. 6. There will never, however, be more tokens in the pool than there are at the start of the game. This is the maximum number of tokens the pool can hold. 7. You may not talk to anyone during the game. Notes to the leader: Do not explain the significance of the tokens before playing the game. The rules are the only instructions the players get. The players will most likely completely empty the pool almost instantly the first time the game is played. Point out that, as it’s impossible to double zero, the game is over. Ask if they’d like to try again. Each student must return all of their tokens to the pool. Continue to play the game for several rounds without giving the students time to communicate with one another in between. When doubling the tokens in the pool, remember there can “never be more tokens in the pool than there are at the start of the game, this is the maximum number of tokens the pool can hold.” Think if the tokens in the pool as fish, in a pond that only has enough room and food to support as many fish (or tokens) as there were in the pool at the start of the game. That number is the pool’s carrying capacity for tokens, and the pool is the commons. After that, ask students how they feel about the way the game worked out. As a group, help the students think of ways they could cooperate to allow more of them to get their 10 tokens without depleting the pool of resources. Play again using these strategies developed by students. Discussion Questions: 1. What do the tokens represent? Renewable resources, such as fish or trees. (Coal, gasoline, oil, iron, are examples of non renewable resources, and therefore aren’t applicable in this exercise.) 2. Can we draw any parallels between the way the group treated the tokens and the way individuals, and society as a whole, uses or overuses renewable resources? DEFORESTATION: cutting trees down without planting replacements or at a rate at which newly planted trees are not given time to grow to maturity before they too are harvested; or cutting down old growth or tropical rainforests which can never be replaced. OVERFISHING: taking so many fish that not enough are left to reproduce and replenish the stocks for the next year. OVERFARMING: depleting the soil of nutrients without giving it time to regenerate (Conversely, we overwhelm nature by producing too much the rate at which we produce carbon dioxide and other forms of pollution far outpaces the time required by air and water to clean themselves). 3. How many tokens were taken out of the pool by each player in the different game variations? How many candies did this generate? How did it make you feel about other members of the group? This discussion question can be done after a few rounds of playing without talking, where only a select few will have received candies, and the others have received none of the benefits from the common pool of tokens. Have those who received candies explain to those that did not why it was OK for them to have candies at the others expense and vice versa to show how the tragedy of the commons can maximize the gains of a few at the expense of the group. 4. How did talking about the game make you play differently? After discussing the strategies, did it seem differing attitudes were behind the ways in which you played the game? Why did some participants take as many tokens as they could reach and others leave some behind? How did this make you feel? 5. Have you experienced a similar situation at home, with friends, in your community? How in the long run, can more benefit if individuals refrain from taking too much? What sort of attitude do we need to have as individuals to achieve the goal of the greatest benefit for all? This game is based on an activity developed by Kurt and Ursula Frischknecht and Karen Zimbelman in Thinking Globally and Acting Locally: Environmental Education Teaching Activities by Lori D. Mann and William B Stapp, ERIC/SMEAC, 1982.