NUDGE: IMPROVING DECISIONS ABOUT HEALTH, WEALTH, AND HAPPINESS by Richard H. Thaler and Cass R. Sunstein Penguin Books, 2009, 312 pp, ISBN 978-0-14-311526-7This book is best described formally as a general explanation of and advocacy for libertarian paternalism, a term coined by the authors in earlier publications. Informally, it is about how leaders, systems, organizations, and governments can nudge people to do the things the nudgers want and need done for the betterment of the nudgees, or of society. It is paternalism in the sense that "it is legitimate for choice architects to try to influence people's behavior in order to make their lives longer, healthier, and better", (p. 5) It is libertarian in that "people should be free to do what they like - and to opt out of undesirable arrangements if they want to do so", (p. 5) The built-in possibility of opting out or making a different choice preserves freedom of choice even though people's behavior has been influenced by the nature of the presentation of the information or by the structure of the decisionmaking system. I had never heard of libertarian paternalism before reading this book, and I now find it fascinating.Written for a general audience, this book contains mostly social and behavioral science theory and models, but there is considerable discussion of structure and process that has roots in mathematical and quantitative modeling. One of the main applications of this social system is economic choice in investing, selecting and purchasing products and services, systems of taxes, banking (mortgages, borrowing, savings), and retirement systems. Other quantitative social choice systems discussed include environmental effects, health care plans, gambling, and organ donations. Softer issues that are also subject to a nudge-based approach are marriage, education, eating, drinking, smoking, influence, spread of information, and politics. There is something in this book for everyone.The basis for this libertarian paternalism concept is in the social theory called "science of choice", the study of the design and implementation of influence systems on various kinds of people. The terms Econs and Humans, are used to refer to people with either considerable or little rational decision-making talent, respectively. The various libertarian paternalism concepts and systems presented are tested and compared in light of these two types of people. Two foundational issues that this book has in common with another book, Network of Echoes: Imitation, Innovation and Invisible Leaders, that was also reviewed for this issue of the Journal are that 1 ) there are two modes of thinking (or components of the brain) - an automatic (intuitive) process and a reflective (rational) process and 2) the need for conformity and the desire for imitation are powerful forces in human behavior. …

Nudge: Improving Decisions about Health, Wealth, and Happiness

The Face of Emotion

Consider the problem of a consumer in a modern supermarket. The typical store sells more than 40,000 items, and in many product categories it offers hundreds of options (for a recent review see Simona Botti and Sheena S. Iyengar 2006). The typical consumer is also time constrained and cannot afford to spend too much time making each selection. To solve this decision problem consumers need to per? form a dynamic search over the set of feasible items under conditions of extreme time pressure and choice overload. This gives rise to several basic questions which are studied in this paper: (i) What are the computational processes deployed by consumers during the search and decision processes, and to what extent are they compatible with standard economic search models? (ii) How do the processes, and their performance, change with the number of options? (iii) Do the computational processes exhibit systematic biases that can be exploited by sellers to manipulate their choices? We study these questions by setting up an experimental version of the consumer's supermarket problem. Hungry subjects are presented with sets of 4,9, or 16 familiar snack items (e.g., Snickers candy bars and Lay's chips) and are asked to make a choice within three seconds. Items are displayed using pictures of the actual pack? ages of items. Besides choices and reaction times, the entire process of visual search is recorded using eye tracking.

https://www.rnl.caltech.edu/publications/pdf/reutskaja2011.pdf

Search Dynamics in Consumer Choice under Time Pressure: An Eye-Tracking Study

The United States is currently engulfed in the most severe financial crisis since the Great Depression. The crisis was triggered by the crash in the real estate “bubble” and amplified by the extreme concentration of risk in a highly leveraged financial sector. Conventional wisdom is that both the bubble and the risk concentration were the result of mistakes in regulatory policy: an expansionary monetary policy during the boom period of the bubble, and failure to reign in the practices of unscrupulous lenders. In this paper we argue that, while correct in some dimensions, this story misses two key structural factors behind the securitization process that supported the real estate boom and the corresponding lever age. First, over the last decade, the US has experienced large and sustained capital inflows from foreigners seeking US assets to store value (Caballero, Emmanuel Farhi, and Pierre-Olivier Gourinchas 2008 ). Second, especially after the NASDAQ/tech bubble and bust, excess world savings have looked predominantly for safe debt investments. This should not be surprising because a large amount of the capital flow into the US has been from foreign central banks and governments that are not expert investors and are merely looking for a store of value (Krishnamurthy and Annette Vissing-Jorgenson 2008). In this paper we develop a stylized model that captures the essence of this environment. The model accounts for three facts observed during the boom and bust phases of the current crisis. First, during a period of good shocks— which we interpret as the period up to the end

/pdf/global-imbalances-and-financial-fragility-6s5ipojpb1.pdf

Global Imbalances and Financial Fragility

In the economic models of old, agents had backward-looking expectations, arising from simple extrapolation or error-correction rules. Then came the rational-expectations revolution in macroeconomics, and in microeconomics the spread and increasing refinements of modern game theory. Agents were now highly sophisticated information processors, who could not be systematically fooled. This approach reigned for several decades until the pendulum swung back with the rise of behavioral economics and its emphasis on “heuristics and biases” (as in Tversky and Kahneman 1974). Overconfidence, confirmation bias, distorted probability weights, and a host of other “wired-in” cognitive mistakes are now common assumptions in many areas of economics. Over the last decade or so, the pendulum has started to swing again toward some form of adaptiveness, or at least implicit purposefulness, in human cognition. In this paper, we provide a perspective into the main ideas and findings emerging from the growing literature on motivated beliefs and reasoning. This perspective emphasizes that beliefs often fulfill important psychological and functional needs of the individual. Economically relevant examples include confidence in ones’ abilities, moral self-esteem, hope and anxiety reduction, social identity, political ideology and religious faith. People thus hold certain beliefs in part because

https://pubs.aeaweb.org/doi/pdfplus/10.1257/jep.30.3.141

Mindful Economics: The Production, Consumption, and Value of Beliefs

This paper studies, theoretically and empirically, the role of overconfidence in political behavior. Our model of overconfidence in beliefs predicts that overconfidence leads to ideological extremeness, increased voter turnout, and stronger partisan identification. The model also makes nuanced predictions about the patterns of ideology in society. These predictions are tested using unique data that measure the overconfidence and standard political characteristics of a nationwide sample of over 3,000 adults. Our numerous predictions find strong support in these data. In particular, we document that overconfidence is a substantively and statistically important predictor of ideological extremeness, voter turnout, and partisan identification. (JEL C83, D03, D72, D83)

/pdf/overconfidence-in-political-behavior-3xiv1lr40d.pdf

Overconfidence in Political Behavior

We conduct an experiment in which subjects face the same questions repeated multiple times, with repetitions of two types: (1) following the literature, the repetitions are distant from each other; (2) in a novel treatment, the repetitions are in a row, and subjects are told that the questions will be repeated. We find that a large majority of subjects exhibit stochastic choice in both cases. We discuss the implications for models of stochastic choice.

/pdf/stochastic-choice-and-preferences-for-randomization-4iq9d5jfhx.pdf

Stochastic Choice and Preferences for Randomization

This paper develops axiomatically a revealed preference theory of reference-dependent choice behavior. Instead of taking the reference for an agent as exogenously given in the description of a choice problem, we suitably relax the Weak Axiom of Revealed Preference to obtain, endogenously, the existence of reference alternatives as well as the structure of choice behavior conditional on those alternatives. We show how this model captures some well-known choice patterns such as the attraction effect. (JEL D11, D81)

Revealed (P)Reference Theory

We investigate the classical Anscombe–Aumann model of decision-making under uncertainty without the completeness axiom. We distinguish between the dual traits of “indecisiveness in beliefs” and “indecisiveness in tastes.” The former is captured by the Knightian uncertainty model, the latter by the single-prior expected multi-utility model. We characterize axiomatically the latter model. Then we show that, under independence and continuity, these two models can be jointly characterized by means of a partial completeness property.

/pdf/incomplete-preferences-under-uncertainty-indecisiveness-in-453c14k1d5.pdf

Incomplete preferences under uncertainty: Indecisiveness in beliefs versus tastes

Despite its normative appeal and widespread use, Bayes’ rule has two well-known limitations: first, it does not predict how agents should react to an information to which they assigned probability zero; second, a sizable empirical evidence documents how agents systematically deviate from its prescriptions by overreacting to information to which they assigned a positive but small probability. By replacing Dynamic Consistency with a novel axiom, Dynamic Coherence, we characterize an alternative updating rule that is not subject to these limitations, but at the same time coincides with Bayes’ rule for “normal” events. In particular, we model an agent with a utility function over consequences, a prior over priors ρ, and a threshold. In the first period she chooses the prior that maximizes the prior over priors ρ--a’ la maximum likelihood. As new information is revealed: if the chosen prior assigns to this information a probability above the threshold, she follows Bayes’ rule and updates it. Otherwise, she goes back to her prior over priors ρ, updates it using Bayes’ rule, and then chooses the new prior that maximizes the updated ρ. We also extend our analysis to the case of ambiguity aversion.

/pdf/modeling-the-change-of-paradigm-non-bayesian-reactions-to-3mbjdl084l.pdf

Pietro Ortoleva

Papers

Overconfidence in Political Behavior

Stochastic Choice and Preferences for Randomization

Revealed (P)Reference Theory

Incomplete preferences under uncertainty: Indecisiveness in beliefs versus tastes

Modeling the Change of Paradigm: Non-Bayesian Reactions to Unexpected News †