Repeated game
The same game played by the same players again and again, so that what someone does today can be answered tomorrow.
Often misread asAssuming repetition by itself produces cooperation, so a prisoner's dilemma played ten times is expected to settle into cooperation because the players get to know one another.
How to see it
The same game again, with yesterday in the room
A repeated game is one stage game played over and over by the same players, each able to see what happened before. What repetition changes is not the payoffs in any single round but the set of available strategies, because a strategy can now make today's action depend on yesterday's behaviour. That is what allows cooperation to be enforced without anyone's preferences changing.
The checkRepetition only buys cooperation when the end is not in sight; with a known final round, backward induction unpicks the whole sequence.
Try itPlay the prisoner's dilemma exactly ten times, with both players knowing it is ten. Solve the tenth round, then the ninth, then the eighth. Note that what destroys cooperation is the known endpoint, not the number of rounds.
Games that show it
Know these first
Leads on to
Easily confused with
Sources
- Friedman, J. (1971). Review of Economic Studies 38(1), 1-12.
- Mailath, G. & Samuelson, L. (2006). Oxford University Press.