We discuss repeated games, aiming to unpack the intuition that the promise of rewards and the threat of punishment in the future of a relationship can provide incentives for good behavior today. In class, we play prisoners' dilemma twice and three times, but this fails to sustain cooperation. The problem is that, in the last stage, since there is then is future, there is no incentive to cooperate, and hence the incentives unravel from the back. We related this to the real-world problems of a lame duck leader and of maintaining incentives for those close to retirement. But it is possible to sustain good behavior in early stages of some repeated games (even if they are only played a few times) provided the stage games have two or more equilibria to be used as rewards and punishments. This may require us to play bad equilibria tomorrow. We relate this to the trade off between ex ante and ex post efficiency in the law. Finally, we play a game in which the players do not know when the game will end, and we start to consider strategies for this potentially infinitely repeated game.

1. Introduction: Five First Lessons
2. Putting Yourselves Into Other People's Shoes
3. Iterative Deletion and the Median-Voter Theorem
4. Best Responses in Soccer and Business Partnerships
5. Nash Equilibrium: Bad Fashion and Bank Runs
6. Nash Equilibrium: Dating and Cournot
7. Nash Equilibrium: Shopping, Standing and Voting on a Line
8. Nash Equilibrium: Location, Segregation and Randomization
9. Mixed Strategies in Theory and Tennis
10. Mixed Strategies in Baseball, Dating and Paying your Taxes
11. Evolutionary Stability: Cooperation, Mutation, and Equilibrium
12. Evolutionary Stability: Social Convention, Aggression, and Cycles
13. Sequential Games: Moral Hazard, Incentives, and Hungry Lions
14. Backward Induction: Commitment, Spies, and First-mover Advantages
15. Backward Induction: Chess, Strategies, and Credible Threats
16. Backward Induction: Reputation and Duels
17. Backward Induction: Ultimatums and Bargaining
18. Imperfect Information: Information Sets and Sub-game Perfection
19. Subgame Perfect Equilibrium: Matchmaking and Strategic Investments
20. Subgame Perfect Equilibrium: Wars of Attrition
21. Repeated Games: Cooperation vs. the End Game
22. Repeated Games: Cheating, Punishment, and Outsourcing
23. Asymmetric Information: Silence, Signaling and Suffering Education
24. Asymmetric Information: Auctions and the Winner's Curse

This course is an introduction to game theory and strategic thinking. Ideas such as dominance, backward induction, Nash equilibrium, evolutionary stability, commitment, credibility, asymmetric information, adverse selection, and signaling are discussed and applied to games played in class and to examples drawn from economics, politics, the movies, and elsewhere.