Cycling in a stochastic learning algorithm for normal form games

In this paper we study a stochastic learning model for 2×2 normal form games that are played repeatedly. The main emphasis is put on the emergence of cycles. We assume that the players have neither information about the payoff matrix of their opponent nor about their own. At every round each player can only observe his or her action and the payoff he or she receives. We prove that the learning algorithm, which is modeled by an urn scheme proposed by Arthur (1993), leads with positive probability to a cycling of strategy profiles if the game has a mixed Nash equilibrium. In case there are strict Nash equilibria, the learning process converges a.s. to the set of Nash equilibria.     

Learning,forecasting and optimizing: An experimental study

Rational Expectations (RE) models have two crucial dimensions: (i) agents on average correctly forecast future prices given all available information, and (ii) given expectations, agents solve optimization problems and these solutions in turn determine actual price realizations. Experimental tests of such models typically focus on only one of these two dimensions. In this paper we consider both forecasting and optimization decisions in an experimental cobweb economy. We report results from four main experimental treatments: (1) subjects form forecasts only, (2) subjects determine quantity only (solve an optimization problem), (3) they do both and (4) they are paired in teams and one member is assigned the forecasting role while the other is assigned the optimization task. All treatments converge to Rational Expectation Equilibrium (REE), but at different speeds. We observe that performance is the best in treatment 1 and the worst in Treatment 3. We further find that most subjects use adaptive rules to forecast prices. Given a price forecast, subjects are less likely to make conditionally optimal production decisions in Treatment 3 where the forecast is made by themselves, than in Treatment 4 where the forecast is made by the other member of their team, which suggests that “two heads are better than one” in term of the speed of finding the REE.     

Why incoherent preferences do not justify paternalism

A variety of recent arguments emerging from behavioural economics claim to undermine the credibility, and even the conceptual coherence, of the economist’s traditional rejection of paternalism. Indeed, some suggest that the incoherent nature of preferences inevitably implies a form of paternalism, since some basis for officiating between expressed preferences is required, and some preferences will be over-ridden in favour of others. This paper reviews and contests these arguments. It argues that markets operate according to a normatively defensible and non-paternalistic principle of mutual advantage, and that this principle does not require preferences to be coherent.      

Can sustainable consumption be learned? A model of cultural evolution

This paper shows how sustainable consumption patterns can spread within a population via processes of social learning even though a strong individual learning bias may favor environmentally harmful products. We present a model depicting how the biased transmission of different behaviors via individual and social learning influences agents' consumption behavior. The underlying learning biases can be traced back to evolved cognitive dispositions. Challenging the vision of a permanent transition toward sustainability, we argue that “green” consumption patterns are not self-reinforcing and cannot be “locked in” permanently.     

The partially cursed and the analogy-based expectation equilibrium

Recent literature has established a link between the fully cursed equilibrium and the analogy-based expectation equilibrium. In this note, even the partially cursed equilibrium is shown to correspond to an analogy-based expectation equilibrium.     

Towards Sustainable Consumption: Economics and Ethical Concerns for the Environment in Consumer Choices

The article examines individual action informed by ethical concerns for the environment as a strategy for moving toward more sustainable consumption. The article first employs a model of rational choice to analyze independent consumer choices among the usually assumed self- and welfare-centered consumers and then expands the model to analyze the implications of other than self- and welfare-centered motivations for consumer choice. The article next analyzes interdependent consumer choices informed by self- and welfare-centered values with the help of a simple game-theoretic model and then moves on to examine the implications of nonutilitarian environmental concerns for interdependent consumer choice in the same game-theoretic framework. The article concludes that although a strategy based on individual action may have limited promise when environmental concerns are widely shared, the case for collective action remains strong because of both efficiency and equity reasons.     

Competitive politics, simplified heuristics, and preferences for public goods

This paper examines the role of simplified heuristics in the formation of preferences for public goods. Political scientists have suggested that voters use simplified heuristics based on the positions of familiar parties to infer how a proposed policy will affect them and to cast a vote in line with their interests and values. Here, we use a two-stage field-survey experiment to investigate how knowledge of party positions affects policy choices. We followed standard procedures in developing an attribute-based choice experiment on alternative land-use policies in Switzerland. In contrast to the usual formulation, however, the hypothetical costs of the proposed policies were formulated as a percentage change in taxes. The benefit of this formulation relative to the usual absolute money amounts is that the credibility of the (hypothetical) costs for respondents does not depend on respondent income. Furthermore, the formulation allowed us to solicit party positions on the proposed policies. Six out of eight contacted parties provided their positions. We then conducted a split-sample mail survey where we included a table of the party positions with a subsample of the questionnaires. We report six main experimental results. (1) The response rate of the survey was unaffected by the party positions. (2) The proportion of no-choice answers was decreased by forty percent relative to the control. (3) The party information significantly affected the choices directly and in interaction with respondents' general attitudes towards public spending for nature and landscape conservation and thus affected the way how individuals mapped from general attitudes to preferences for specific policies. (4) The information interacted with educational level in only eight out of forty choice sets, suggesting that even the more educated relied on simplified heuristics. (5) Respondents who knew the party positions were more sensitive to the tax attribute. (6) For respondents with medium and higher tax bills, the resulting willingness-to-pay estimates were decreased by a factor of two to ten relative to the control. These findings suggest that the party information helped the respondents to articulate more consistent preferences than in the treatment without the party information.     

Economics and psychology in the twenty-first century

This paper begins by exploring four different possible formsof relationship between economics and psychology, which havedifferent connotations in terms of the relative status of thetwo disciplines. It then focuses on the future for one of these,psychological economics. After setting out the hardcore axiomsand positive and negative heuristics of a research programmein psychological economics, it explores institutional and psychologicalbarriers to the success of such a research programme in thecontext of both research and teaching.     

Adaptation and complexity in repeated games

The paper presents a learning model for two-player infinitely repeated games. In an inference step players construct minimally complex inferences of strategies based on observed play, and in an adaptation step players choose minimally complex best responses to an inference. When players randomly select an inference from a probability distribution with full support the set of steady states is a subset of the set of Nash equilibria in which only stage game Nash equilibria are played. When players make ‘cautious’ inferences the set of steady states is the subset of self-confirming equilibria with Nash outcome paths. When players use different inference rules, the set of steady states can lie between the previous two cases.     

On designing economic agents that behave like human agents

This paper explores the idea of constructing theoretical economic agents that behave like actual human agents and using them in neoclassical economic models. It does this in a repeated-choice setting by postulating artificial agents who use a learning algorithm calibrated against human learning data from psychological experiments. The resulting calibrated algorithm appears to replicate human learning behavior to a high degree and reproduces several stylized facts of learning. It can therefore be used to replace the idealized, perfectly rational agents in appropriate neoclassical models with calibrated agents that represent actual human behavior. The paper discusses the possibilities of using the algorithm to represent human learning in normal-form stage games and in more general neoclassical models in economics. It explores the likelihood of convergence to long-run optimality and to Nash behavior, and the characteristic learning time implicit in human adaptation in the economy.