Bounded Rationality In Macroeconomics

How do people behave in new situations in which previous experience is not useful? The recent changes in Eastern Europe, for example, are unprecedented and there is not an available model on which to base the mechanisms that will govern the economics in this region. The concept of "bounded (orlimited) rationality" is being developed to analyze behavior in such situations. In this book Thomas Sargent describes and interprets the recent work in the area, especially in statistics, econometrics, networks and artificial intelligence. He focuses on examples designed to illustrate the issuesinvolved and the kinds of questions that are being asked and answered in this research. He points to further potential positive developments of the theory as well as some of its limitations.

This book challenges the generally accepted theories of classical economics, explaining why the expected utility theory, even if it were true, fails to be of much help in solving economic controversies.

The form of bounded rationality characterizing the representative agent is key in the choice of the optimal monetary policy regime. While inflation targeting prevails for myopia that distorts agents' inflation expectations, price level targeting emerges as the optimal policy under myopia regarding the output gap, revenue, or interest rate. To the extent that bygones are not bygones under price level targeting, rational inflation expectations is a minimal condition for optimality in a behavioral world. Instrument rules implementation of this optimal policy is shown to be infeasible, questioning the ability of simple rules à la Taylor (1993) to assist the conduct of monetary policy. Bounded rationality is not necessarily associated with welfare losses.

The concept of rational expectations has played a hugely important role in economics over the years. Dealing with the origins and development of modern approaches to expectations in micro and macroeconomics, this book makes use of primary sources and previously unpublished material from such figures as Hicks, Hawtrey and Hart. The accounts of the 'founding fathers' of the models themselves are also presented here for the first time. The authors trace the development of different approaches to expectations from the likes of Hayek, Morgenstern, and Coase right up to more modern theorists such as Friedman, Patinkin, Phelps and Lucas. The startling conclusion that there was no 'Rational Expectations Revolution' is articulated, supported and defended with impressive clarity and authority. A necessity for economists across the world, this book will deserve its place upon many an academic bookshelf.

This short book introduces the field of bounded rationality to a beginning readership in economics. It is intended to be a tour of the key concepts involved in the modelling of bounded rationality, the approaches that have been adopted and some of the most revealing, and at times surprising, findings that have been generated. The book explores how bounded rationality has been used in economic models to shed light on real life behaviour and how doing so has led to specific policy implications that would otherwise have gone unappreciated. The exposition is intended to be non-technical and free from any mathematical expressions and workings and the focus throughout is primarily on the behaviour of individuals or organisations within given situations rather than on macroeconomic concerns. How the field has evolved since the 1950s and the strengths and weaknesses of its current research programme, including its relationship with behavioural economics, are assessed.

The purpose of this book is to publish the ideas of the late Herbert Simon and sympathetic economists, on the subject of bounded rationality, economics, cognitive science and related disciplines, and to reprint some of Professor Simon's classic papers which have appeared in journals not widely read by economists. Not only on account of his Nobel Prize in Economics, but also because of the widespread applications of his ideas and theories, it is especially valuable to readers to have a book of this kind at the present time. Currently in this whole field, there is increasing emphasis on computer-related theory building. Herbert Simon, beginning from the time when microcomputers did not exist, was a pioneer of this approach. The book begins with an edited transcript of a colloquium, held between Herbert Simon and a group of Italian economists in Italy in 1988. It continues with the reprinted Simon papers and papers by three scholars, Raymond Boudon, Massimo Egidi and Riccardo Viale coming from different disciplines but holding a common interest in bounded rationality and ends with a response by a sympathetic economist, Robin Marris.

Motivated by recent developments in the bounded rationality and strategic complementarity literatures, we examine an intentionally simple and stylized aggregative economic model, when the assumptions of fully rational expectations and no strategic interactions are relaxed. We show that small deviations from rational expectations, taken alone, lead only to small deviations from classical policy- ineffectiveness, but that the situation can change dramatically when strategic complementarity is introduced. Strategic complementarity magnifies the effects of even small departures from rational expectations, producing equilibria with policy effectiveness, output persistence and multiplier effects.