Bargaining and network structure: An experiment

We consider bargaining in a bipartite network of buyers and sellers, who can only trade with the limited number of people with whom they are connected. We perform an experimental test of a graph-theoretic model that yields unique predictions about equilibrium prices for the networks in our sessions. The results diverge sharply depending on how a connection is made between two separate simple networks, typically conforming to the theoretical directional predictions. Payoffs can be systematically affected even for agents who are not connected by the new link, and we find evidence of a form of social learning.     

Cooperators and reciprocators: A within-subject analysis of pro-social behavior

We perform a within-subject analysis of pro-social behavior in the public-good and gift-exchange game. We find that participants classified as cooperators in the public-good game tend to reciprocate higher wages in the gift-exchange game with higher levels of effort. Non-cooperators do not exhibit such tendency. Both types offer similar wages.     

Does truth win when teams reason strategically?

We study behavior in the race game with the aim of assessing whether teams can create synergies. The race game has the advantage that the optimal strategy depends neither on beliefs about other players nor on distributional or efficiency concerns. Our results reveal that teams not only outperform individuals but that they can also beat the “truth-wins” benchmark. In particular, varying the length of the race game we find that the team advantage increases with the complexity of the game.     

Modeling Expectation Formation Involving Several Sources of Information

Abstract. Experimental studies of expectation formation of subjects are predominantly limited to the prediction of one single time series despite the practical relevance of expectations in situations with multiple sources of information. In this paper, we report on an experiment in which subjects are given time series (indicators) as additional information for the judgemental forecast of a stationary time series. The quality and the number of these indicators are varied in three versions of a forecasting experiment. We explore the effects on forecasting accuracy and we test the average forecasts of the subjects for consistency with the rational expectations hypothesis. A simple heuristic is presented that explains the average forecasting behavior better than the rational expectations if indicators are presented to the subjects. It is demonstrated by a simulation study that this result is representative for the considered stationary stochastic processes.     

The Effect of Communication Media on Cooperation

Abstract. We examine how communication affects cooperation with the help of seven standard public goods experiments that only differ with respect to the medium of pre‐play communication. Our treatments include bidirectional and unidirectional communication via (mostly electronic) auditory and/or visual channels. The results suggest that successful cooperation is attributable to the opportunity of ‘coordinating’ behavior in the communication phase. Furthermore, both the level and the stability of cooperation significantly interact with the communication medium, even though the content of communication is remarkably similar across the communication treatments.     

Honesty in tournaments

We apply the die rolling experiment of Fischbacher and Föllmi-Heusi (2013) to a two-player tournament incentive scheme. Our treatments vary the prize spread. The data highlights that honesty is more pronounced when the prize spread is small.     

Imitation and the evolution of Walrasian behavior: Theoretically fragile but behaviorally robust

A well-known result by Vega-Redondo (1997) [18] implies that in symmetric Cournot oligopolies, imitation leads to the Walrasian outcome. We show that this result is not robust to the slightest asymmetry in costs, since every outcome where agents choose identical actions will be played some fraction of the time in the long run. We then conduct experiments to check this fragility. We obtain that, contrary to the theoretical prediction, the Walrasian outcome is a good predictor of market outcomes. Finally, we suggest a new theory based on a mix of imitation and other learning processes that explains subjects' behavior fairly well.     

Collusion as public monitoring becomes noisy: Experimental evidence

This paper uses laboratory experiments to test the implications of the theory of repeated games on equilibrium payoffs and estimate strategies in an infinitely repeated prisoners' dilemma game with imperfect public monitoring. We find that subjects' payoffs (i) decrease as noise increases, and (ii) are lower than the theoretical maximum for low noise, but exceed it for high noise. Under the assumption that the subjects' strategy uses thresholds on the public signal for transition between cooperation and punishment states, we find that the best fitting strategy simply compares the most recent public signal against a single threshold.     

The effects of costless pre-play communication: Experimental evidence from games with Pareto-ranked equilibria

Cheap talk is shown to facilitate coordination on the unique efficient equilibrium in experimental order-statistic games. This result is roughly consistent with theoretical predictions according to which cheap talk promotes efficient Nash play. The evidence concerning the mechanisms that theory appeals to is mixed: Frequent agreement of messages and actions is consistent with messages being viewed as self-committing. Risk in the underlying game and the absence of self-signaling messages may explain why message profiles are not unanimous. Time-varying message profiles can be interpreted as evidence for players trying to negotiate equilibria and/or trying to rely on secret handshakes.     

Out-of-equilibrium performance of three Lindahl mechanisms: Experimental evidence

We describe an experimental comparison of the out-of-equilibrium performance of three allocation mechanisms designed to achieve Lindahl outcomes as Nash equilibria: the mechanisms due to Walker (1981), Kim (1993), and Chen (2002). We find that Chen?s mechanism, which is supermodular, converges closest and most rapidly to its equilibrium. However, we find that the properties that move subjects toward equilibrium in Chen?s mechanism typically generate sizeable taxes and subsidies when not in equilibrium, and correspondingly large budget surpluses and deficits, which typically far outweigh the surplus created by providing the public good. The Kim mechanism, on the other hand, converges relatively close to its equilibrium and exhibits much better out-of-equilibrium efficiency properties.     

Conditional punishment

We elicit human conditional punishment types by conducting experiments. We find that their punishment decisions to an individual are on average significantly positively proportional to other members’ punishment decisions to that individual.     

Imitation—theory and experimental evidence

We introduce a generalized theoretical approach to study imitation and subject it to rigorous experimental testing. In our theoretical analysis we find that the different predictions of previous imitation models are mainly explained by different informational assumptions, and to a lesser extent by different behavioral rules. In a laboratory experiment we test the different theories by systematically varying information conditions. We find significant effects of seemingly innocent changes in information. Moreover, the generalized imitation model predicts the differences between treatments well. The data provide support for imitation on the individual level, both in terms of choice and in terms of perception. Furthermore, individuals’ propensity to imitate more successful actions is increasing in payoff differences.     

Who to punish? Individual decisions and majority rule in mitigating the free rider problem

We study a voluntary contributions mechanism in which punishment may be allowed, depending on subjects’ voted rules. We found that out of 160 group votes, even when groups had no prior experience with unrestricted punishment, no group ever voted to allow unrestricted punishment and no group ever allowed punishment of high contributors. Over a series of votes and periods of learning we found a distinct reluctance to allow any punishment at the beginning, with a gradual but clear evolution toward allowing punishment of low contributors. And groups allowing punishment of only low contributors achieved levels of cooperation and efficiency that are among the highest in the literature on social dilemmas.     

Overconfidence as a social bias: Experimental evidence

The overconfidence bias is discussed extensively in economic studies, yet fails to hold experimentally once monetary incentives and feedback are implemented. We consider overconfidence as a social bias. For a simple real effort task, we show that, individually, economic conditions effectively prevent overconfidence. By contrast, the introduction of a very basic, purely observational social setting fosters overconfident self-assessments. Additionally, observing others’ actions effectively eliminates underconfidence compared to the individual setting.     

Cooperation and framing effects in provision point mechanisms: Experimental evidence

Andreoni (1995) showed that pure framing effects may influence contribution in Voluntary Contribution Mechanisms (VCM) by comparing a standard public goods game, called the positive frame condition (giving to the public good), with a negative frame condition (taking from the public good) where the subjects' choice to purchase a private good makes the other subjects worse off. This paper aims at testing the robustness of such framing effects in the context of Provision Point Mechanisms (PPM). Our approach is original in that it combines both framing and provision point dimensions by comparing maintaining (taking from the public good) and creating (giving to the public good) contexts using Provision Point experiments. Consistent with previous findings, we find that individuals tend to be less cooperative in the maintaining frame than in the creating frame. Our results also show that the framing effects are stronger under a PPM than under a VCM and increase with the provision point level. These results may have important consequences for the management of environmental resources.     

Social status and group norms: Indirect reciprocity in a repeated helping experiment

In the economic literature, reciprocity is typically studied in situations of repeated interaction between two individuals. It refers to one individual rewarding kind acts of the other or punishing hostile acts. In contrast, this paper studies indirect reciprocity, where a cooperative action is rewarded by a third actor, not involved in the original exchange. We provide experimental evidence on indirect reciprocity. The experiment is based on the ‘repeated helping game’ developed by Nowak and Sigmund (J. Theoret. Biol. 194 (1998) 561; Nature 393 (1998) 573), involving random pairing in large groups. Pairs consist of a donor and a recipient. Donors decide whether or not to provide costly ‘help’ to the recipients they are matched with, based on information about the recipient's behavior in encounters with third parties. We observe clear evidence of indirect reciprocity. Many decision-makers respond to the information about previous decisions (whether or not to help others) of the recipients. In our experiments, this indirect reciprocity is largely based on norms about how often the recipient should have helped others in the past. We show that these norms develop similarly within groups of interacting subjects, but distinctly across groups. This leads to the emergence of group norms.     

The endowment effect and intertemporal choice: a laboratory investigation

We present a laboratory investigation of intertemporal choice (i.e., elicited discount rates) allowing for the influence of the endowment effect. Consistent with the previous literature, we hypothesize that the endowment effect in an intertemporal choice setting results in substantially higher discount rates relative to when individuals treat the resources in question as found money. Our results support this hypothesis and our experimental design provides a new protocol for conducting choice experiments wherein the endowment effect is an important determinant of behaviour.     

Optimal dynamic risk sharing when enforcement is a decision variable

Societies provide institutions that are costly to set up, but able to enforce long-run relationships. We study the optimal decision problem of using self-governance for risk sharing or governance through enforcement provided by these institutions. Third-party enforcement is modelled as a costly technology that consumes resources, but permits the punishment of agents who deviate from ex ante specified allocations. We show that it is optimal to employ the technology whenever commitment problems prevent first-best risk sharing and fixed costs are sufficiently low, but never optimal to provide incentives exclusively via this technology. Commitment problems then persist and the optimal incentive structure changes dynamically over time with third-party enforcement monotonically increasing in the relative inequality between agents.     

Heterogeneous producers facing common shocks: An overlapping-generations example

An analytically tractable model of a competitive, full-information economy is provided in which, for some parameter values, entry and exit over the course of the business cycle is concentrated among small firms. This model is intended to make the logical point that the relatively high sensitivity of small firms to business-cycle fluctuations does not necessarily indicate the presence of informational or incentive constraints in financial markets.