Case-Based Reasoning, Social Dilemmas, and a New Equilibrium Concept

RePEc: Research Papers in Economics, 2011

The game-theoretic assumption of 'common knowledge of rationality' leads to paradoxes when rationality is represented in a Bayesian framework as cautious expected utility maximisation with independent beliefs (ICEU). We diagnose and resolve these paradoxes by presenting a new class of formal models of players' reasoning, inspired by David Lewis's account of common knowledge, in which the analogue of common knowledge is derivability in common reason. We show that such models can consistently incorporate any of a wide range of standards of decision-theoretic practical rationality. We investigate the implications arising when the standard of decision-theoretic rationality so assumed is ICEU. Short title Common reasoning in games Keywords Common reasoning; common knowledge; common knowledge of rationality; David Lewis; Bayesian models of games.

Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 2012

LIST OF FIGURES Agraïments A la meua família, pel seu suport incondicional, paciència,ànims i comprensió. Per haverse esforçat sempre en donar-me l'oportunitat de poder arribar fins ací, en tots els sentits. Als amics, amigues, companys i companyes, pels bons moments d'humor, de compartir experiències, sentiments i suport mutu. Als companys i companyes del GTI-IA, per ajudar-me sempre que ho he necessitat i pel bon ambient de treball. A Stella, per haver compartit els seus coneixements i les seues investigacions amb mi. Pels llargs dies de treball i discussions on he aprés molt. I per la seua inestimable ajuda en tot el meu treball. A Vicente, per confiar en mi i donar-me l'oportunitat de treballar amb ell. Per compartir la seua experiència i dirigir-me correctament. Pel seu suport, comprensió i ajuda en aquest i altres treballs. Moltes gràcies a tots, sense vosaltres res no tindria sentit. Recently, the ASPIC project 1 [Amgoud et al., 2006] made an effort to consolidate the work done in argumentation languages and protocols, argument visualisation and editing tools and, generally, in argumentation frameworks for MAS. However, the argumentation infrastructure proposed in this project does not offer support for agent societies and their

ArXiv, 2021

It has been argued that one role of social constructs, such as institutions, trust and norms, is to coordinate the expectations of autonomous entities in order to resolve collective action situations (such as collective risk dilemmas) through the coordination of behaviour. While much work has addressed the formal representation of these social constructs, in this paper we focus specifically on the formal representation of, and associated reasoning with, the expectations themselves. In particular, we investigate how explicit reasoning about expectations can be used to encode both traditional game theory solution concepts and social mechanisms for the social dilemma situation. We use the Collective Action Simulation Platform (CASP) to model a collective risk dilemma based on a flood plain scenario and show how using expectations in the reasoning mechanisms of the agents making decisions supports the choice of cooperative behaviour.

Archive for Mathematical Logic, 2021

In strategic situations, agents base actions on knowledge and beliefs. This includes knowledge about others' strategies and preferences over strategy profiles, but also about other external factors. Bernheim and Pearce in 1984 independently defined the game theoretic solution concept of rationalizability, which is built on the premise that rational agents will only take actions that are the best response to some situation that they consider possible. This accounts for other agents' rationality as well, limiting the strategies to which a particular agent must respond, enabling further elimination until the strategies stabilize. We seek to generalize rationalizability to account not only for actions, but knowledge of the world as well. This will enable us to examine the interplay between action based and knowledge based rationality. We give an account of what it means for an action to be rational relative to a particular state of affairs, and in turn relative to a state of knowledge. We present a class of games, Epistemic Messaging Games (EMG), with a communication stage that clarifies the epistemic state among the players prior to the players' actions. We use a history based model, which frames individual knowledge in terms of local projections of a global history. With this framework, we give an account of rationalizability for subclasses of EMG.

SSRN Electronic Journal, 2000

The implausibility of the extreme rationality assumptions of Nash equilibrium has been attested by numerous experimental studies with human players. In particular, the fundamental social dilemmas such as the Traveler's dilemma, the Prisoner's dilemma, and the Public Goods game demonstrate high rates of deviation from the unique Nash equilibrium, dependent on the game parameters or the environment in which the game is played. These results inspired several attempts to develop suitable solution concepts to more accurately explain human behaviour. In this line, the recently proposed notion of cooperative equilibrium, [5], [6], based on the idea that players have a natural attitude to cooperation, has shown promising results for single-shot games. In this paper, we extend this approach to iterated settings. Specifically, we define the Iterated Cooperative Equilibrium (ICE) and show it makes statistically precise predictions of population average behaviour in the aforementioned domains. Importantly, the definition of ICE does not involve any free parameters, and so it is fully predictive.

Economics of Governance, 2001

Why is rent-seeking so endemic in societies? Might it not be possible to design a Pareto-improving social decision rule that sidesteps the inefficient waste of resources resulting from conflict? We study this question for a multiplayer contest. We assume that a benevolent planner knows the winning payoffs, the effectiveness of each rent-seeker, that the cost of expending resources is isoelastic, and that it is the same across all players. But she does not know the precise value of this elasticity. We show that this minimal lack of information leads to the impossibility of a Pareto-improving social decision rule, as long as there are at least four agents.

Standard game theory cannot explain the selection of payoff-dominant outcomes that are best for all players in common-interest games. Theories of team reasoning can explain why such mutualistic cooperation is rational. They propose that teams can be agents and that individuals in teams can adopt a distinctive mode of reasoning that enables them to do their part in achieving Pareto-dominant outcomes. We show that it can be rational to play payoff-dominant outcomes, given that an agent group identifies. We compare team reasoning to other theories that have been proposed to explain how people can achieve payoff-dominant outcomes, especially with respect to rationality. Some authors have hoped that it would be possible to develop an argument that it is rational to group identify. We identify some large-probably insuperable-problems with this project and sketch some more promising approaches, whereby the normativity of group identification rests on morality.

Psychological Inquiry, 2012

Economica, 2011

Acta Psychologica, 2008

The experiments reported in our target article provide strong evidence of collective utility maximization, and the findings suggest that team reasoning should now be included among the social value orientations used in cognitive and social psychology. Evidential decision theory offers a possible alternative explanation for our results but fails to predict intuitively compelling strategy choices in simple games with asymmetric team-reasoning outcomes. Although many of our experimental participants evidently used team reasoning, some appear to have ignored the other players' expected strategy choices and used lowerlevel, nonstrategic forms of reasoning. Standard payoff transformations cannot explain the experimental findings, nor team reasoning in general, without an unrealistic assumption that players invariably reason nonstrategically.