Advances in Behavioral Economics contains influential second-generation contributions to behavioral economics. Building on the seminal work by Kahnemann, Strotz, Thaler, Tversky, and others, these contributions have established behavioral economics as an important field of study in economics. In this essay, I discuss aspects of the research strategy and methodology of behavioral economics, as exemplified by the contributions to Advances.

A model of fashion cycles is developed in which designs are used as a signaling device in a "dating game." A monopolist periodically creates a new design. Over time the price of the design falls as it spreads across the population. Once sufficiently many consumers own the design it is profitable to create a new design and thereby render the old design obsolete. The paper gives conditions under which all consumers would be better off by banning the use of fashion. Competition among designers may lead to less frequent changes in fashion and to higher prices than monopoly.

A collective choice problem specifies a finite set of alternatives from which a group of expected utility maximizers must choose. We associate a collective pseudo market with every collective choice problem and establish the existence and efficiency of pseudo Lindahl equilibrium (PLE) allocations. We also associate a cooperative bargaining problem with every collective choice problem and define a set-valued solution concept, the ω-weighted Nash bargaining set where ω is a vector of welfare weights. We provide axioms that characterize the ω-weighted Nash bargaining set. Our main result shows that ω-weighted Nash bargaining set payoffs are also the PLE payoffs of the corresponding collective pseudo market with the same utility functions and incomes ω. We define a pseudo core for collective pseudo markets and show that pseudo Lindahl equilibria are in the pseudo core. We characterize the set of PLE outcomes of discrete allocation problems and show that they contain the set of pseudo Walrasian equilibrium outcomes.

We analyse political contests (campaigns) between two parties with opposing interests. Parties provide costly information to voters who choose a policy. The information flow is continuous and stops when both parties quit. Parties' actions are strategic substitutes: increasing one party's cost makes that party provide more and its opponent provide less information. For voters, parties' actions are complements and hence raising the advantaged party's cost may be beneficial. Asymmetric information adds a signalling component resulting in a belief threshold at which the informed party's decision to continue campaigning offsets other unfavourable information.

We construct an infinite horizon model of harmful addiction. Consumption is compulsive if it differs from what the individual would have chosen had commitment been available. A good is addictive if its consumption leads to more compulsive consumption of the same good. We analyse the welfare implications of drug policies and find that taxes on drugs decrease welfare while prohibitive policies may increase welfare. We also analyse the agent's demand for voluntary commitment (“rehab”). For appropriate parameters, the model predicts a cycle of addiction where the agent periodically checks into rehab. Between these visits his drug consumption increases each period.

We analyse preferences over finite decision problems in order to model decision-makers with “changing tastes”. we provide conditions on these preferences that identify the Strotz model of consistent planning. building on an example given by Peleg and Yaari (1973), we show that for problems with infinitely many choices, Strotz's representation of preferences may not be well defined. For that case, we propose a well-defined approximation which is empirically indistinguishable from the Strotz preference that is being approximated.

We consider a market in which an expert must exert costly but unobservable effort to identify the service that meets the consumer's need. In our model, experts offer competing contracts and the consumer may gather multiple opinions. We explore the incentives that a competitive sampling of prices and opinions provides for experts to exert effort and find that there is a tension between price competition and the equilibrium effort. In particular, the equilibrium fails to realize the second best welfare optimum. An intervention, that limits price competition via price control, increases welfare.

We introduce and analyze expected uncertain utility theory (EUU). A prior and an interval utility characterize an EUU decision maker. The decision maker transforms each uncertain prospect into an interval-valued prospect that assigns an interval of prizes to each state. She then ranks prospects according to their expected interval utilities. We define uncertainty aversion for EUU, use the EUU model to address the Ellsberg Paradox and other ambiguity evidence, and relate EUU theory to existing models.

We develop and analyze a model of random choice and random expected utility. A decision problem is a finite set of lotteries that describe the feasible choices. A random choice rule associates with each decision problem a probability measure over choices. A random utility function is a probability measure over von Neumann–Morgenstern utility functions. We show that a random choice rule maximizes some random utility function if and only if it is mixture continuous, monotone (the probability that a lottery is chosen does not increase when other lotteries are added to the decision problem), extreme (lotteries that are not extreme points of the decision problem are chosen with probability 0), and linear (satisfies the independence axiom).

To study the behavior of agents who are susceptible to temptation in infinite horizon consumption problems under uncertainty, we define and characterize dynamic self-control (DSC) preferences. DSC preferences are recursive and separable. In economies with DSC agents, equilibria exist but may be inefficient; in such equilibria, steady state consumption is independent of initial endowments and increases in self-control. Increasing the preference for commitment while keeping self-control constant increases the equity premium.