Decision and Rationality seminar

The Decision and Rationality seminar is a joint seminar between the IHPST and GREHEC laboratories, which aims to bring together researchers in decision theory, economics, philosophy of social science and psychology who are interested in the theme of rational choice. The organisers are Mikael Cozic (Paris 12 & IHPST), Brian Hill (HEC Paris & IHPST) and Olivier L'Haridon (GREGHEC & Paris 4).

Le séminaire "Décision et rationalité" est organisé par l'Institut d'Histoire et de Philosophie des sciences et des Techniques (IHPST) et le Groupement de Recherche et des Etudes en Gestion à HEC (GREGHEC). Il a pour vocation de rassembler, autour de la théorie du choix rationnel, des chercheurs issus de la théorie de la décision, de l'économie, de la philosophie des sciences sociales et de la psychologie. Ce séminaire est sous la responsabilité de Mikael Cozic (Paris 12 & IHPST), Brian Hill (HEC Paris & IHPST) et Olivier L'Haridon (GREGHEC & Paris 4).

Program 2010-2011

• 12 November. Jonathan ZVESPER (Oxford). Complete Belief Models.
  
  Session: 16h, salle Weil, ENS Ulm (45 rue d'Ulm, 75005 Paris)
  
  Abstract: In Interactive Epistemology, we can formalise a notion of epistemic "cautiousness", that one agent does not exclude any possibility for the other agent -- that she takes every possibility for his `type' into account. This notion of cautiousness, relevant to the epistemic foundation of some solution concepts in game theory, leads to two limitative results [bk06, bfk08] that we will present in some detail. The first of these is in effect a two-person or interactive version of Russell's paradox. Once it is summarised, we will present our own positive possibility result reported in [zp08] and then delve into the logic of the impossibility argument. We then explain our work reported in [az10], giving a category-theoretic version of the impossibility result, as well as a coalgebraic way of obtaining possibility results.

  
  

• 17 January. Barry Sopher (Rutgers). Group Decision Making with Uncertainty: An Experimental Examination of Information Aggregation over Communication Networks.
  
  Session: 16h, IHPST 13 rue du Four, 75006 Paris, Métro Mabillon (2ème étage)
  
  Abstract: We study small group decision making in an environment where decision makers receive independent and private signals about the probability of payoff-relevant states of the world. Two policies, one risky and one safe, are available for adoption. We use laboratory experimental methods. Subjects are assigned randomly to groups of five decision makers in each of 12 rounds of play. In later rounds subjects are given individual payoff biases favoring or disfavoring one of the policies. Subjects communicate over given network architectures and then vote to determine which policy to adopt. We study connected and unconnected networks. Communication is free-form, via computer chat boxes. Subjects know the payoff biases of other subjects to whom they are connected. We find that connected networks are best at promoting full information aggregation, and also lead more often to the socially best policy being adopted. In rounds without payoff biases communication is generally truthful (in reporting own signals), while in rounds with payoff biases the truthfulness of communication is about 80% overall. Without biases a full network in which all agents are connected performs best. With biases, a more hierarchical “star” network performs better, in terms of revealing truthful information Insight into this appears to lie in how self-reported beliefs depend (or not) upon others biases.

  
  

• 18 January. Atelier Agrégation des jugements
  
  Session: Université Paris Descartes, 45, rue des Saints Pères – Paris 6ème (Salle J237, Bâtiment Jacob, 2ème étage).
  
  Gabriella Pigozzi (LAMSADE, Université Paris-Dauphine). Sur l’Agrégation de jugements dans un système d’argumentation.
  
  Sébastien Konieczny (CRIL, Université d’Artois). Fusion de croyances et théorème du jury.
  
  Lewis Kornhauser (New York University & Sciences Po Paris). Legal deliberation and the theory of collective choice.
  
  Franz Dietrich (London School of Economics). Epistemic democracy with defensible premises.
  
  

  
  

Previous Years

Information on the program for 2009-2010 to be found here.

Information on the program for 2008-2009 to be found here.

Information on the program for 2007-2008 to be found here.