Models of Reasoning

Abstract

Esta tesis estudia la aplicación de modelos de racionamiento humano en la área de la economía. El objetivo del análisis es observar el efecto que tienen distintos modelos de adaptación y aprendizaje sobre el resultado final de varios juegos.<br/>En los tres trabajos que forman la tesis se analizan distintos juegos. <br/>En el primero el juego es el Dilema del Prisionero y el objetivo es estudiar la influencia del aprendizaje social e individual o imitación sobre el resultado del juego. Los resultados demuestran que la elección de uno de estos modelos determina el resultado final.<br/>El segundo trabajo se dedica a crear en modelo dinámico de formación de coaliciones en el que los individuos no saben el valor que tiene cada coalición para ellos. El modelo crea un proceso de Markov no estacionario. Nuestros resultados demuestran que los puntos fijos del sistema se pueden aproximar por una secuencia de dinámicas perturbadas en los que los jugadores saben el valor de las coaliciones.<br/>En el ultimo trabajo analizamos la dinámica de un mercado usando un modelo computacional. El enfoque del trabajo es la influencia de los hábitos de los consumidores sobre la estructura del mercado. Los resultados demuestran que algunas de las características del comportamiento de los consumidores pueden sostener la diversidad en calidades y tamaño de las empresas en el mercado.

This thesis focuses on studying the way in which individuals' adaptation mechanizms influence their behavior and the outcomes in different games. In all the models presented here the emphasis is put on the adaptation process and its elements, rather than on the equilibrium behavior of the players. <br/>The thesis consists of three papers.<br/>The first one focuses on the importance of the way the information is exchanged in the context of Repeated Prisoner's Dilemma game. In Chapter 2 we build a simulation model imitating the structure of human reasoning in order to study how people face a Repeated Prisoner's Dilemma game. The results are ranged starting from individual learning in which case the worst result -defection- is obtained, passing through a partial imitation, where individuals could end up in cooperation or defection, and reaching the other extreme of social learning, where mutual cooperation can be obtained. The influence of some particular strategies on the attainment of cooperation is also considered. Those differences in the results of the three scenarios we have constructed suggest that one should be very careful when deciding which one to choose.<br/>Chapter 3 studies the process of coalition formation when players are unsure about the true benefit of belonging to a given coalition. Under such strong incomplete information scenario, we use a Case-Based Decision Theory approach to study the underlying dynamic process. We show that such process can be modeled as a non-stationary Markov process. Our main result shows that any rest point of such dynamics can be approached by a sequence of similar "perturbed" dynamics in which players learn all the information about the value of each possible coalition<br/>In Chapter 4 we study the dynamics of an experience good market using a two-sided adaptation Agent Based Computational Economics (ACE) model. The main focus of the analysis is the influence of consumers' habits on market structure. Our results show that given characteristics of consumers' behavior might sustain the diversity in the market both in terms of quality and firms' size. We observe that the more adaptive one side of the market is, the more the market reflects its interests.