时间：11月12日（周四）13:15 - 14:30

地点：北京大学经济学院302

主持老师：石凡奇（经院）；胡岠（国发院）；王子伟（光华）

参与老师：胡涛，石凡奇，周扬帆（经院）；汪浩，胡岠，邢亦青（国发院）；翁翕，刘烁，王子伟（光华）

主讲人：Peio Zuazo-Garin (Associate Professor of Economics, NYU Shanghai)

题目：Approximate Common Belief in Rationality: The Limits of Backward and Forward Induction

摘要：

We show that even the slightest doubt about others' rationality suffices for rendering dynamic reasoning static. We approximate common belief in rationality with a dynamic p-belief operator: a player is required to believe that others are rational with probability at least p whenever conditional probability cannot be applied. We apply this operator to define forward and backward induction variants of common p-belief in rationality that coincide with the standard notions for p = 1—strong and backward rationalizability, respectively. Our main result establishes that a strategy is consistent with the forward (resp. backward) induction version of common p-belief in rationality for every p < 1, if and only if it is consistent with common initial belief in rationality (Ben Porath, 1997). We show that an analogous result holds for a p-belief version of subgame perfect equilibrium and weak sequential equilibrium. The results unveil a striking discontinuity of dynamic reasoning: every static prediction becomes valid as soon as p < 1. The approach also explains sustained cooperation in Centipede games and the finitely repeated Prisoner’s Dilemma, and the empirical failure of backward and forward induction in various settings. Finally, we apply the framework to dynamic Bayesian games to reassess the classic equivalence between robustness to payoff-uncertainty (Dekel & Fudenberg, 1990) and robustness to uncertain rationality (Börgers, 1994).

主讲人介绍：

Peio Zuazo-Garin is an Associate Professor of Economics at NYU Shanghai. He is a theorist with a focus on foundational aspects of game theory and decision theory, in particular robustness and the modeling of bounded cognition. His research has been published in the Review of Economic Studies, Theoretical Economics, and Games and Economic Behavior, among others. Prior to joining NYU Shanghai, he was an Associate Professor at the International College of Economics and Finance at HSE University and an Assistant Professor at the University of the Basque Country. He has also held research positions at Universitat Pompeu Fabra and Universitat Rovira i Virgili, and has been a visitor at Northwestern University, Tel Aviv University, and the Hebrew University of Jerusalem.