This study is the first to attempt to isolate a relationship between cognitive activity and equilibration to a Nash Equilibrium. Subjects, while undergoing fMRI scans of brain activity, participated in second price auctions against a single competitor following predetermined strategy that was unknown to the subject. For this auction there is a unique strategy that will maximize the subjects’ earnings, which is also a Nash equilibrium of the associated game theoretic model of the auction. As is the case with all games, the bidding strategies of subjects participating in second price auctions most often do not reflect the equilibrium bidding strategy at first but with experience, typically exhibit a process of equilibration, or convergence toward the equilibrium. This research is focused on the process of convergence.

In the data reported here subjects participated in sixteen auctions, after which all subjects were told the strategy that will maximize their revenues, the theoretical equilibrium. Following that announcement, sixteen more auctions were performed. The question posed by the research concerns the mental activity that might accompany equilibration as it is observed in the bidding behavior. Does brain activation differ between being equilibrated and non-equilibrated in the sense of a bidding strategy? If so, are their differences in the location of activation during and after equilibration? We found significant activation in the frontal pole especially in Brodmann's area 10, the anterior cingulate cortex, the amygdala and the basal forebrain. There was significantly more activation in the basal forebrain and the anterior cingulate cortex during the first sixteen auctions than in the second sixteen. The activity in the amygdala shifted from the right side to the left after the solution was given.

This study reports experiments that examine outcomes when agents choose between a payment scheme that rewards based on absolute performance (i.e., piece rate) and a scheme that rewards based on relative performance (i.e., a tournament). Holding total payments in the tournament constant, performance is higher when the tournament option is winner-take-all compared to a graduated tournament (i.e., second and third-place performers also receive a payment). Performance is higher in the winner-take all tournaments even among participants that choose the piece-rate option. While there is a modest amount of overcrowding, there are no significant differences in overcrowding across conditions. Entry rates into the tournament and the relative ability of tournament entrants (compared to non-entrants in the same condition) are higher in the graduated tournament condition than the winner-take-all conditions. Consequently, the winner-take-all tournament is more efficient than the graduated tournament (incentive effects are stronger and the overcrowding is about the same), but the graduated tournament provides a more effective mechanism to identify the most capable performer in a talent pool.

The paper considers what can be inferred about experimental subjects’ time preferences for consumption from responses to laboratory tasks involving tradeoffs between sums of money at different dates, if subjects can reschedule consumption spending relative to income in external capital markets. It distinguishes three approaches identifiable in the literature: the straightforward view; the separation view; and the censored data view. It shows that none of these is fully satisfactory and discusses the resulting implications for intertemporal decision-making experiments.

This paper reports new data from both selling and buying versions of the Becker-DeGroot-Marschak (BDM) procedure. First, when using the selling version of BDM, the cross-sectional mean of CRRA risk preference parameter estimates shifts from a value consistent with “as if” risk-seeking behavior in the early baseline to a value closer to “as if” risk neutrality in the late baseline. Second, when using the buying version of BDM, the cross-sectional mean of CRRA risk preference parameter estimates does not appear to change over time in a statistically significant manner. The cross-sectional mean from the late baseline of the buying version of BDM is closer to “as if” risk neutrality and to the late baseline estimates from the selling version of BDM than it is to either early baseline estimates from the selling version of BDM or typical estimates from the first price auction. Use of dominated offers is correlated with deviations from “as if” risk neutrality; this suggests the possibility that the early deviations from “as if” risk neutrality reflect errors.

Recently, there has been a Renaissance for multi-level selection models to explain the persistence of unselfish behavior in social dilemmas, in which assortative/correlated matching plays an important role. In the current study of a multi-round prisoners’ dilemma experiment, we introduce two correlated matching procedures that match subjects with similar action histories together. We discover significant treatment effects, compared to the control procedure of random matching. Particularly with the weighted history matching procedure we find bifurcations regarding group outcomes. Some groups converge to the all-defection equilibrium even more pronouncedly than the control groups do, while other groups generate much higher rate of cooperation, which is also associated with higher relative reward for a typical cooperative action. All in all, the data show that cooperation does have a much better chance to persist in a correlated/assortative-matching environment, as predicted in the literature.

This paper reports an experiment designed to detect the influence of strategic uncertainty on behavior in order statistic coordination games, which arise when a player's best response is an order statistic of the cohort's action combination. Unlike previous experiments using order statistic coordination games, the new experiment holds the payoff function constant and only changes cohort size and order statistic.

We experimentally investigate if free information disadvantages a player relative to when information is unavailable. We study an Ultimatum game where the Proposer, before making an offer, can obtain free information about the Responder's minimum acceptable offer. Theoretically, the Proposer should obtain the information and play a best reply to the Responder's minimum acceptable offer. Thus the Responder should get the largest share of the surplus. We find that an increasing number of Proposers become informed over time. Moreover, the proportion of Proposers who use the information to maximize money earnings increases over time. The majority of information-acquiring Proposers, however, refuse to offer more than one-half and play a best reply only to Responders who accept offers of one-half or less. This, together with a substantial proportion of Proposers who choose to remain uninformed, means that the availability of free information backfires for Proposers only by a little.

We perform an experiment on a pure coordination game with uncertainty about the payoffs. Our game is closely related to models that have been used in many macroeconomic and financial applications to solve problems of equilibrium indeterminacy. In our experiment, each subject receives a noisy signal about the true payoffs. This game (inspired by the “global” games of Carlsson and van Damme, Econometrica, 61, 989-1018, 1993) has a unique strategy profile that survives the iterative deletion of strictly dominated strategies (thus a unique Nash equilibrium). The equilibrium outcome coincides, on average, with the risk-dominant equilibrium outcome of the underlying coordination game. In the baseline game, the behavior of the subjects converges to the theoretical prediction after enough experience has been gained. The data (and the comments) suggest that this behavior can be explained by learning. To test this hypothesis, we use a different game with incomplete information, related to a complete information game where learning and prior experiments suggest a different behavior. Indeed, in the second treatment, the behavior did not converge to equilibrium within 50 periods in some of the sessions. We also run both games under complete information. The results are sufficiently similar between complete and incomplete information to suggest that risk-dominance is also an important part of the explanation.

We present a transfer-seeking model of political economy that links the theory of Becker (1983) with Tullock-type models of politically contestable rents. In our model the size of the transfer is determined endogenously, and over-dissipation of rents is predicted even under conditions of risk-neutrality and perfect rationality. We implement an empirical test of this model by collecting behavioral data in a laboratory experiment. We confirm the existence of behavior that leads to over-dissipation of rents in games with both symmetric and asymmetric political power. To the extent that the transfer-seeking costs are social costs, our findings imply that the total costs of running government might be greatly underestimated if the value of the rent is used as a proxy for the rent-seeking cost. We also confirm the hypotheses that lowering the political power of one player can lead to smaller rent-seeking expenditures and to larger transfers

In this paper we propose and test a contracting mechanism, Multi-Contract Cost Sharing (MCCS), for use in the management of a sequence of projects. The mechanism is intended for situations where (1) the contractor knows more about the true costs of various projects than does the contracting agency (adverse selection), and (2) unobservable effort on the part of the contractor may lead to cost reductions (moral hazard). The proposed process is evaluated in an experimental environment that includes the essential economic features of the NASA process for the acquisition of Space Science Strategic missions. The environment is complex and the optimal mechanism is unknown. The design of the MCCS mechanism is based on the optimal contract for a simpler related environment. We compare the performance of the proposed process to theoretical benchmarks and to an implementation of the current NASA ‘cost cap’ procurement process. The data indicate that the proposed MCCS process generates significantly higher value per dollar spent than using cost caps, because it allocates resources more efficiently among projects and provides greater incentives to engage in cost-reducing innovations.

Laboratory experiments are used to evaluate the extent to which players in games can coordinate investments that diminish the probability of losses due to security breaches or terrorist attacks. In this environment, economically sensible investments may be foregone if their potential benefits are negated by failures to invest in security at other sites. The result is a coordination game with a desirable high- payoff, high-security equilibrium and an undesirable low-security equilibrium that may result if players do not expect others to invest in security. One unique feature of this coordination situation is that investment in security by one player generates a positive externality such that all other players’ expected payoffs are increased, regardless of those other players’ investment decisions. Coordination failures are pervasive in a baseline experiment with simultaneous decisions, but coordination is improved if players are allowed to move in an endogenously determined sequence. In addition, coordinated security investments are observed more often when the largest single security threat to individuals is preventable by their own decisions to invest in security. The security coordination game is a “potential game,” and the success of coordination on the more secure equilibrium is related to the notion of potential function maximization and basin of attraction.

We revisit the result that, in laboratory independent private values auction, the first-price sealed bid and descending clock (or Dutch) implementations are not isomorphic. We investigate the hypothesis that this arises from framing and presentation effects. Our design focuses on a careful construction of subject interfaces that present the two environments as similarly as possible. Our sessions also consist of more auction periods to test whether any initial framing effects subsequently decrease over time. We find the difference between the implementations persists. To further investigate the difference, we report on an intermediate implementation which operates like the Dutch auction, but in which the clock continues to tick to the lowest price without informing bidders when others have bid on the object.

Economists and psychologists have long argued the origin of wealth influences individual behavior. In a previous study (Cherry et al., 2005), we found the origin of endowment did not significantly affect behavior in linear public good games with summation contribution technology. In such games, however, both Nash behavior (everybody gives nothing) and social optimal behavior (everybody gives the entire endowment) call for symmetric levels of contributions. Results from this new study indicate that the origin of wealth might matter in more asymmetric situations, such as in a best-shot public good game with heterogeneous groups.

We experimentally investigate whether individuals can reliably detect cooperators (the nice(r) people) in an anonymous decision environment involving “connected games.” Participants can condition their choices in an asymmetric prisoners’ dilemma and a trust game on past individual (their partner's donation share to a self-selected charity) and social (whether their partner belongs to a group with high or low average donations) information. Thus, the two measures of niceness are the individual donation share in the donation task, and the cooperativeness of one's choice in the two games. We find that high donors achieve a higher-than-average expected payoff by cooperating predominantly with other high donors. Group affiliation proved to be irrelevant.

z-Tree (Zurich Toolbox for Ready-made Economic Experiments) is a software for developing and conducting economic experiments. The software is stable and allows programming almost any kind of experiments in a short time. In this article, I present the guiding principles behind the software design, its features, and its limitations.

We reconsider evidence from experiments that claim to show that using “house money” in standard public goods experiments has no effect on behavior. We show that it does have an effect when one examines the data using appropriate statistical methods that consider individual-level responses and account for the error structure of the panel data.

This paper presents a laboratory collective resistance (CR) game to study how different forms of non-binding communication among responders can help coordinate their collective resistance against a leader who transgresses against them. Contrary to the predictions of analysis based on purely self-regarding preferences, we find that non-binding communication about intended resistance increases the incidence of no transgression even in the one-shot laboratory CR game. In particular, we find that the incidence of no transgression increases from 7 percent with no communication up to 25-37 percent depending on whether communication occurs before or after the leader's transgression decision. Responders’ messages are different when the leaders can observe them, and the leaders use the observed messages to target specific responders for transgression.