1. So Long From ECONOMICS 1040 : S TRATEGY, C ONFLICT & C OOPERATION So Long From ECONOMICS 1040 : S TRATEGY, C ONFLICT & C OOPERATION Spring 2007 W 7:35-9:35 Emerson 108 Instructor: Robert Neugeboren neugebor@fas.harvard.edu Teaching Fellow: Rajiv Shankar rshankar@fas.harvard.edu Website: http://www.courses.fas.harvard.edu/~ext21946/ Office Hours: W 3-4 51 Brattle St.

2. Unit IV: Thinking about Thinking Choice and Consequence Fair Play Learning to Cooperate Summary and Conclusions 5/9

3. Summary and Conclusions Tournament submission deadline: May 11 by 5PM Graduate Paper deadline: May 19 by 5PM. Review Class: Wed, May 16. Review Section: Tues, May 22. Final Exam: Wed, May 23.

4. Game theory was developed to “solve” simple parlor games. In the 1940s and ‘50s, it was applied to international conflict A THEORY OF WAR Schelling “reoriented” game theory to seek ways of resolving conflict as an alternative to war. In the Post-war period, attention turned to expanding trade among Western economies EXCHANGE The Prisoner’s Dilemma exposed a deep problem at the heart of game theory, calling forth a new approach. Finally, analysis of repeated games offered a way to understand today’s global problems COOPERATION The Evolution of Game Theory

5. 192819441950 19601984 1994 19491989 ZEROSUM GAMESNONZEROSUM GAMESREPEATED GAMES MINIMAX THEOREMNASH EQUILIBRIUMFOLK THEOREM PRISONER’S DILEMMA WAR EXCHANGECOOPERATION PARLOR GAMESNUCLEAR TRADE SUSTAINABLE ARMS RACE DEVELOPENT Theory of Games Strategy & ConflictThe Evolution & Economic Behavior of Cooperation Soviet A-TestThe End of the Cold War Nobel: Harsanyi, Selten & Nash The Evolution of Game Theory

6. “And here it becomes emphatically clear that the intellectual processes of choosing a strategy in pure conflict and choosing a strategy of coordination are of wholly different sorts …. In the pure-coordination game, the player’s objective is to make contact with the other player through some imaginative process of introspection, of searching for shared clues; in the minimax strategy of a zero-sum game … -- one’s whole objective is to avoid any meetings of the mind, even an inadvertent one” Schelling, 1960, p. 96. The Evolution of Game Theory

7. Once we move to nonzero-sum games, however, the status of game theory grows ambiguous: Coordination Games Bargaining Games Repeated Games Public Goods Games PLAY BEST RESPONSE STRATEGY? There may be more than one, and the “right” one will depend on what the other/s choose\s. PLAY DOMINANT STRATEGY (when it exists)? PD! Multiple and/or inefficient equilibria

8. 192819441950 19601984 1994 19491989 ZEROSUM GAMESNONZEROSUM GAMESREPEATED GAMES MINIMAX THEOREMNASH EQUILIBRIUMFOLK THEOREM PRISONER’S DILEMMA WAR EXCHANGECOOPERATION PARLOR GAMESNUCLEAR TRADE SUSTAINABLE ARMS RACE DEVELOPENT Theory of Games Strategy & ConflictThe Evolution & Economic Behavior of Cooperation Soviet A-TestThe End of the Cold War Nobel: Harsanyi, Selten & Nash The Evolution of Game Theory A fourth paradigm? EVOLUTIONARY GAMES ?? ESS

9. Summary & Conclusion [W]here trust and good faith do not exist and cannot be made to by our acting as though they did, we may wish to solicit advice from the underworld, or from ancient despotism, on how to make agreements when trust and good faith are lacking and there is no legal recourse for breach on contract. The ancient exchanged hostages, drank from the same glass to demonstrate the absence of poison, met in public places (…) and even deliberately exchanged spies to facilitate transmittal of authentic information. It seems likely that a well-developed theory of strategy could (…) discover modern equivalents that, though offensive to our taste, may be desperately needed in the regulation of conflict. – Schelling,1960, p. 20

10. For Further Interest Binmore, K.Game Theory & the Social Contract, II (1998). Gintis, H.Game Theory Evolving (2000). Kreps, D.Game Theory and Economic Modelling (1994). Raiffa, H.The Art and Science of Negotiation (1982).

11. Preliminary Tournament Results

16. So Long From ECONOMICS 1040 : S TRATEGY, C ONFLICT & C OOPERATION So Long From ECONOMICS 1040 : S TRATEGY, C ONFLICT & C OOPERATION Spring 2007 W 7:35-9:35 Emerson 108 Instructor: Robert Neugeboren neugebor@fas.harvard.edu Teaching Fellow: Rajiv Shankar rshankar@fas.harvard.edu Website: http://www.courses.fas.harvard.edu/~ext21946/ Office Hours: W 3-4 51 Brattle St.