Iterated Prisioners Dilemma

The Prisoners Dilemma is a mathematical game in which locally optimal choices lead the players to betray each other even though all would do better if all cooperated. It predicts the collapse of society into a puddle of selfishness.

When the dilemma is iterated - that is, repeated over and over again - the prediction changes. An Iterated Prisoner's Dilemma gives the players something to gain from cooperation and trust, and a way to punish betrayers. The difference relies on players being able to identify each other, so they know when they are playing against the same opponent and can reward or punish them according to their behaviour in the previous games.

In small communities, all dilemmas are iterated. Players necessarily have the same opponents because there is simply no-one else to play against. Also, everyone gets to know everyone else. The upshot is that nobody can get away with cheating.

As the community size scales upward, players come to know each other by reputation rather than directly. Although a given player may not have played against a given opponent personally, they can have seen how the opponent behaves in other games and respond appropriately. Nobody wants the reputation of a cheat.

This again relies on players having persistent identity across games. In a large online community, most games are played with strangers. Identity is usually left unclear or totally absent. Cheats can go then unpunished. This gives rational players a local incentive to cheat, even if it leads to a less-optimal result (of community collapse) in the long run. The logic becomes, quite correctly, "If I don't, somebody else will". Even if all players are acting in good faith, trust is fragile in these circumstances.

In order to build large communities (Wiki and others) we should strive to turn Prisoners Dilemmas into IteratedPrisonersDilemmas.

Source: MeatBall:IteratedPrisionersDilemma∞

CategoryWiki