Belief Formation and Evolution in Public Good Games.

We analyze first-order beliefs in a variation of the Public Good Game. We show that (1) the role that belief elicitation plays in the experiment affects both the contribution behavior and beliefs, and (2) framing influences stated beliefs, as much as contribution behavior. In the second part of the paper, we study the role of heterogeneity in the formation of initial beliefs, and provide an empirical model of the belief up-dating process. Subjects use the past experience, stressing the role of experience that comes from situations similar to the current ones.Beliefs, Public Good, Framing, Experiment, (Belief) Learning

Social Preferences - Literature Survey

This paper surveys the theories of social preferences. Social preferences are based on that people not only care about their own well-being, but they have a certain concern with payoffs and/or actions of others. We classify two approaches: distributional and intention-based models, and later discuss models that combine both theories. In order to provide a better illustration of the discussed models, we derive predictions of these models for two classic experimental protocols: ultimatum game and public good game with punishment. These predictions are compared with the stylized facts of these two games.

Giving it now or later: altruism and discounting

We experimentally study the e¤ect of time on altruism. By postponing payments in a standard Dictator game, subjects allocate a future payment between themselves and others. Since both the payoffs of the Dictator and the Receiver are delayed until the same time, standard intertemporal utility maximization would predict that waiting time should not affect the Dictator's choice. In this respect, we observe that Dictators' decisions are not affected, as long as the time interval between the decision and payment is not large. On the other hand, for large time gaps, subjectsbecome more self-interested.Altruism, Discounting, Dictator game, Intertemporal choice.

Social Preferences - Literature Survey

This paper surveys the theories of social preferences. Social preferences are based on that people not only care about their own well-being, but they have a certain concern with payoffs and/or actions of others. We classify two approaches: distributional and intention-based models, and later discuss models that combine both theories. In order to provide a better illustration of the discussed models, we derive predictions of these models for two classic experimental protocols: ultimatum game and public good game with punishment. These predictions are compared with the stylized facts of these two games.Financial support from the Spanish Ministry of Education and Science (AP-2004-1893) is greatfully acknowledged

Strategic Interaction and Conventions

The scope of the paper is the literature that employs coordination games to study social norms and conventions from the viewpoint of game theory and cognitive psychology. We claim that those two alternative approaches are complementary, as they provide different insights to explain how people converge to a unique system of self-fulfilling expectations in presence of multiple, equally viable, conventions. While game theory explains the emergence of conventions relying on efficiency and risk considerations, the psychological view is more concerned with frame and labeling effects. The interaction between these alternative (and, sometimes, competing) effects leads to the result that coordination failures may well occur and, even when coordination takes place, there is no guarantee that the convention eventually established will be the most efficient.conventions, social norms, behavioral game theory

Fixed priced plus rationing: An experiment

This paper theoretically and experimentally explores a fixed price mechanism inwhich, if aggregate demand exceeds supply, bidders are proportionally rationed. Ifdemand is uncertain, in equilibrium bidders overstate their true demand in order toalleviate the effects of being rationed. This effect is the more intense the lower theprice, and bids reach their upper limit for sufficiently low prices. In the experiment weobserve a significant proportion of equilibrium play. However, subjects tend to overbidthe equilibrium strategy when prices are low and underbid when prices are high. Weexplain the experimental evidence by a simple model in which the probability of adeviation is decreasing in the expected loss associated with itFixed price mechanism, rationing, experimental economics

Limited memory can be beneficial for the evolution of cooperation

We study a dynamic process where agents in a network interact in a Prisoner’s Dilemma. The network not only mediates interactions, but also information: agents learn from their own experience and that of their neighbors in the network about the past behavior of others. Each agent can only memorize the last h periods. Evolution selects among three preference types: altruists, defectors and conditional cooperators. We show - relying on simulation techniques - that the probability of reaching a cooperative state does not relate monotonically to the size of memory h. In fact it turns out to be optimal from a population viewpoint that there is a finite bound on agents’ memory capacities. We also show that it is the interplay of local interactions, direct and indirect reputation and memory constraints that is crucial for the emergence of cooperation. Taken by itself, none of these mechanisms is sufficient to yield cooperation.evolution, reputation, bounded memory, cooperation.

Learning in Network Games

We report the findings of an experiment designed to study how people learn and make decisions in network games. Network games offer new opportunities to identify learning rules, since on networks (compared to e.g. random matching) more rules differ in terms of their information requirements. Our experimental design enables us to observe both which actions participants choose and which information they consult before making their choices. We use this information to estimate learning types using maximum likelihood methods. There is substantial heterogeneity in learning types. However, the vast majority of our participants' decisions are best characterized by reinforcement learning or (myopic) best-response learning. The distribution of learning types seems fairly stable across contexts. Neither network topology nor the position of a player in the network seem to substantially affect the estimated distribution of learning types.Basque Government (IT-223-07) and the Spanish Ministry of Science and Innovation (ECO2009-09120) for financial support.Dutch Science Foundation (NWO, VENI grant 016.125.040

(Anti-) Coordination in Networks

We study (anti-) coordination problems in networks in a laboratory experiment. Participants interact with their neighbours in a fixed network to play a bilateral (anti-) coordination game. Our main treatment variable is the extent to which players are heterogeneous in thenumber of connections (neighbors) they have. Other network characteristics are held constant across treatments. We find the following results. Heterogeneity in the number of connections dramatically improves the rate of succesful coordination. In addition, even though there is a multiplicity of Nash equilibria theoretically, a very sharp selection is observed empiricaly: the most connected player can impose her preferred Nash equilibrium almost always and observed Nash equilibria are such that all links are coordinated. As a second treatment variation we let agents decide endogenously on the amount of information they would like to have and find that local (endogenous) information is equally efficient in ensuring succesful coordination as full information. We provide an intuitive explanation of these facts which is supported by our data.microeconomics ;

Strategic Interaction and Conventions

The scope of the paper is the literature that employs coordination games to study social norms and conventions from the viewpoint of game theory and cognitive psychology. We claim that those two alternative approaches are complementary, as they provide different insights to explain how people converge to a unique system of self-fulfilling expectations in presence of multiple, equally viable, conventions. While game theory explains the emergence of conventions relying on efficiency and risk considerations, the psychological view is more concerned with frame and labeling effects. The interaction between these alternative (and, sometimes, competing) effects leads to the result that coordination failures may well occur and, even when coordination takes place, there is no guarantee that the convention eventually established will be the most efficient.Financial support from MICINN (ECO2009-09120), MEC (SEJ 2007-62656 and Consolider-Ingenio 2010, CSD2006-00016), MIUR (PRIN 2007MCKEYA), Gobierno Vasco (DEUI, IT-313-07), Generalitat Valenciana (Research Group 03/086) and Instituto Valenciano de Investigaciones Económicas (IVIE) is gratefully acknowledged