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The Comedy of the Trojans

In The Tragedy of the Commons (Science vol. 162, p. 1243), Garrett Hardin discussed situations in which each individual can benefit from some action (grazing another cow on shared pasture, or having another child) which, if everyone does it (bringing the number of cows or people above some optimum), leaves everyone worse off.

Similarly, self-interest may keep individuals from taking some positive action which, if everyone did it, would provide each individual with a net benefit (i.e., more than enough to offset individual costs). These are often called "public goods problems." Similar situations involving interactions of only two individuals are known as "Prisoner's Dilemmas." Tragedies of the commons are not limited to interactions among humans.

Here are some examples:
1) Coastal cities worldwide could be destroyed by rising sea levels from melting polar ice, but even a major decrease in carbon dioxide emissions in any one country would not be enough to stop global warming.
2) Most public radio listeners would gladly send a bigger contribution to support their favorite station, if that would eliminate on-air fund-drives. But it wouldn't.
3) Shorter wheat plants produce more seeds per acre, because they waste less energy on taller stems. But natural selection favors taller plants, because they shade out shorter neighbors, which compete with them for soil resources as well as light.

Of course, I will also be discussing possible ways of reversing the tragedy of the commons. Hence the name of this blog, which has nothing to do with a play about a religious leader who reluctantly agreed that it's OK to use condoms to prevent the spread of AIDS -- only within marriage, of course! -- so long as people don't start using them for birth control.

My own research focuses on the evolution of cooperation between bacteria and plants and the implications of various tragedies of the commons (like the wheat example above) for agriculture. See my Department of Ecology Evolution and Behavior web page for recent papers and my old UC Davis web page for older ones. See also my other blog, This Week in Evolution.

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