In an experiment on resource use, green stars (tokens) represent resources; the circles represent the players. Tokens grow fastest in cells with four occupied neighbors. Tokens cannot “grow” in occupied cells, or in cells lacking neighboring tokens. Players use arrow keys to move; the space bar captures a token.
The “tragedy of the commons” is an old problem in ecology: if all the villagers can graze their cows on the village commons, they are likely destroy it by over-grazing.
Ironically, maximizing individual income harms everybody in the long run. Fisheries and irrigation supplies are also prone to the tragedy of the commons, and that raises a question: What conditions are most likely to prevent the tragedy and maximize production?
For a new study, Marco Janssen, a assistant professor of human evolution and social change at Arizona State University, and colleagues built a video game designed to mimic a natural productive system.
Video shows five players who do not communicate collecting tokens from a common resource. In front of your eyes, players reenact the tragedy of the commons.
In nature, plants and animals can reproduce to fill “ecological niches” – but only if the niches are open and close to existing plants and animals. The same rules pertained in the game: tokens “grow” the fastest when open squares touch several occupied squares.
Rules of the road
Video shows that players who communicated harvest the common resource with more care — and collect more resources, even though the rules of the game itself were the same as in the above video. Notice that players tend to stay in the areas they chose during the text-chats?
To determine what circumstances would allow the players to capture the most tokens and get the highest return, the researchers varied the rules governing player behavior. In some trials, players could communicate with each other via text message. In other trials, players could punish others who misbehaved by charging them one token. In some trials, players could both communicate and punish; in other trials they could do neither.
Without changing the rules controlling token growth, the researchers then measured how much of the resource the players could capture during six, four-minute trials with different rules on player behavior.
Simply vacuuming up all the tokens as fast as possible produced the smallest harvests, because there was no place for new tokens to grow. Yet in the absence of communication, vacuuming was the ideal strategy for each player, even though they all participated in a tragedy of the commons.
Videos courtesy Marco Janssen and Allen Lee, Arizona State University
When the participants could communicate before each trial, they often discussed strategy. “Typically they decided, ‘We should not harvest immediately, we should let the resource grow a little bit,'” Janssen says. “Most groups decided to split the resource into individual areas, and, 30 seconds before the end, to take as much as they could; it’s best for earnings to end up with nothing on the board.”
[quicktime width=”582″ height=”590″ vspace=”5″]http://whyfiles.org/wp-content/uploads/2010/04/after-communication.mp4[/quicktime]
The most productive strategies all involved communication, which helped the players “understand the setting better, develop a group feeling, and develop some rules,” Janssen says. “I hope this will stimulate people to look at what make communications effective. There has not been much study on that” in research on using resources.
Punishment, typically used to retaliate for misbehavior, caused mistrust and reduced both cooperation and total harvest. But punishment was tricky, even when combined with communication, Janssen found. “It might be good to have communication with an option to punish, but if you actually use punishment, it may reduce mutual trust. But if you cannot use the stick, people may not cooperate. You have to be very careful when you use force.”