Philosophy, Politics and Economics
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University of Pennsylvania
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I Cannot Cheat on You after We Talk (joint with C. Bicchieri) in The Prisoner’s Dilemma, ed. M. Peterson. Cambridge University Press, 2015.

(This is part of a collection of research papers on social dilemmas from different perspectives. The list of contributors to this volume includes K. Binmore, G. Bonanno, C. Holt, etc.)

Experimental evidence on pre-play communication supports a “focusing function of communication” hypothesis. Relevant communication facilitates cooperative, pro-social behavior because it causes a shift in individuals’ focus towards strategies dictated by some salient social norm. After reviewing the formal foundations for a general theory of conformity to social norms, we provide an original application illustrating how a framework that allows for different conjectures about norms is able to capture the focusing function of communication and to explain experimental results.




Self-Serving Conformism (joint with G. Charness and M. Naef). We examine a novel class of conformist preferences that is within the realm of belief-dependent motivations, in that the peers’ expectations about others’ behavior may affect every group-member’s welfare. Similar social-preference motivations (such as guilt-aversion) have been inferred from evidence of a belief-behavior correlation, but the issue of causality has been called into question. In examining conformism, we propose a design that verifies the presence of the relevant causality direction while ruling out alternative social-preference motivations. Our data reveal “self-servingly conformist” behavior in that subjects choose to match their strategy to the peers’ expectations when it is in their material interest to do so.




A Notion of Prominence for Strategic Games (joint with S. Bhatia). Identifying the best course of action in games with multiple equilibria is a long-standing unresolved issue in strategic interaction. The concept of prominence as a criterion for equilibrium selection has been suggested, but has remained for the most part an informal notion, without a psychologically grounded characterization. In this paper we propose one such characterization: by drawing on existing theories of human memory, language, and decision making we define prominence in terms of frequency of exposure. In particular, we consider games where strategies are denoted by natural language labels, and we measure the prominence of each strategy by how often its label occurs in natural language corpora. Our specification of prominence yields sharp quantitative predictions about behavior in coordination and discoordination problems. Here we present three studies designed to test such predictions, and show that individuals do select strategies that fulfill our definition of prominence and they furthermore do so in a (boundedly) rational manner.




A Dynamic Model of Belief-Dependent Conformity to Social Norms. Human conduct is often guided by “conformist preferences”, which thrive on behavioral expectations within a society, with conformity being the act of changing one’s behavior to match the purported beliefs of others. Despite a growing research line considering preferences for a fair outcome allocation, economic theories do not explain the fundamental conditions for some social norm – whether of fairness or not – to be followed. Inspired by Bicchieri’s account of norms (C.Bicchieri, The Grammar of Society. CambridgeUP [2006]),  I develop a behavioral theory of norm conformity building on the Battigalli-Dufwenberg “psychological” framework (P.Battigalli and M.Dufwenberg, Dynamic Psychological Games, J.Econ.Theory, 144:1-35 [2009]).




A Model of Conventions with Incompletely-Aware Players. Behavioral regularities in situations where there are several ways agents may coordinate their actions – for mutual benefit – are widely documented. In everyday language such regularities are often referred to as conventions. David Lewis [1969] defined conventions as a regular pattern of behavior that is a strict Nash equilibrium in a coordination game with multiple strict Nash equilibria, while Thomas Schelling [1960] drew attention to the importance of contextual cues in coordination problems: players solve coordination games by resorting to apparently insignificant factors that make one of the feasible strategies salient. Consistently with the intuitions of Lewis and Schelling, this essay proposes a theoretical framework for the player’s own perception of the game so as to show that a convention is in place whenever members of a social group use, and expect others to use, similar conceptual schemes: this is done by implementing a system of multiple state spaces ordered by expressive power, and a notion of the players’ (un)awareness, in such a way as to provide a precise link between the players’ perception of the game and the associated strategy labels. Further, in order to capture the different degrees of salience that players may attach to their labeled strategies, this paper introduces a binary relation allowing the salience comparison of pairs of alternatives. To sum up, conventions arise as the result of a four-step procedure: (i) perception; (ii) labellings; (iii) salience comparison; (iv) expected utility-maximization. Examples are given.

Escher - Belvedere

M. C. Escher: Belvedere