Payments or Persuasion: Common Pool Resource Management with Price and Non-price Measures

We use lab experiments to study policies that address common pool resource overuse. We look at a price mechanism, specifically a Pigouvian subsidy, and four non-price interventions. The non-price policies are information alone, information with a normative message, communication alone, and normative messages with communication allowed. In all experiment sessions, no intervention occurs in the first seven and last seven rounds, allowing us to examine the effects of introducing and taking away a policy. The subsidy leads to near-efficient extraction, but surprisingly leads groups that were not over-extracting to also reduce extraction. This over-compliance decreases efficiency, although on net the subsidy is the most efficiency-enhancing intervention. Information provision, communication, normative appeals, and normative appeals combined with communication all reduce over-extraction (though by less than the subsidy) without exacerbating over-compliance; however, the effects of information alone and communication alone are small and not robust. The non-price policies cause a decline in over-extraction of from 0.549 (information) to 11.441 % (normative appeals with communication). These effects are of the same order of magnitude as the effects seen in major field studies of conservation messaging. The subsidy has the worst persistence properties (after the intervention ceases), while normative messages with communication have the best.     

Decentralized computation procurement and computational robustness in a smart market

Summary. Several `smart market' mechanisms have recently appeared in the literature. These mechanisms combine a computer network that collects bids from agents with a central computer that selects a schedule of bids to fill based upon maximization of revenue or trading surplus. Potential problems exist when this optimization involves combinatorial difficulty sufficient to overwhelm the central computer. This paper explores the use of a computation procuring clock auction to induce human agents to approximate the solutions to discrete constrained optimization problems. Economic and computational properties of the auction are studied through a series of laboratory experiments. The experiments are designed around a potential application of the auction as a secondary institution that approximates the solution to difficult computational problems that occur within the primary `smart market', and show that the auction is effective and robust in eliciting and processing suggestions for improved schedules. Received: November 5, 1996; revised version: September 30, 1997     

Communication in games of incomplete information: Two players

We study the effect of communication in two-person games of incomplete information. We show that for any two-player game of incomplete information, any rational mediated communication mechanism outcome (satisfying a Nash domination condition) can be implemented as the perfect Bayesian equilibrium of a cheap-communication extension of the original game.     

COMMUNICATION AND MARKET SHARING: AN EXPERIMENT ON THE EXCHANGE OF SOFT AND HARD INFORMATION

We study the role of communication in collusive market sharing. In a series of Cournot oligopoly experiments with multiple markets, we vary the information that firms can exchange: hard information—verifiable information about past conduct—and soft information—unbinding information about future conduct. We find that the effect of communication on the firms' ability to collude depends on the type of information available: Whereas market prices increase only slightly with hard information, the price raise due to soft information is substantial. Our results point to the types and contents of communication that should be of particular concern to antitrust authorities.     

Misery loves company: Social regret and social interaction effects in choices under risk and uncertainty

Extensive field evidence shows individuals? decisions in settings involving uncertainty depend on their peers? decisions. One hypothesized cause of peer group effects is social interaction effects: an individual?s utility from an action is enhanced by others taking the same action. We employ a series of controlled laboratory experiments to study the causes of peer effects in choice under uncertainty. We find strong peer group effects in the laboratory. Our design allows us to rule out social learning, social norms, group affiliation, and complementarities as possible causes for the observed peer group effects, leaving social interaction effects as the likely cause. We use a combination of theory and empirical analysis to show that preferences including “social regret” are more consistent with the data than preferences including a taste for conformity. We observe spillover effects, as observing another?s choice of one risky gamble makes all risky gambles more likely to be chosen.     

The communication requirements of social choice rules and supporting budget sets

The paper examines the communication requirements of social choice rules when the (sincere) agents privately know their preferences. It shows that for a large class of choice rules, any minimally informative way to verify that a given alternative is in the choice rule is by verifying a “budget equilibrium”, i.e., that the alternative is optimal to each agent within a “budget set” given to him. Therefore, any communication mechanism realizing the choice rule must find a supporting budget equilibrium. We characterize the class of choice rules that have this property. Furthermore, for any rule from the class, we characterize the minimally informative messages (budget equilibria) verifying it. This characterization is used to identify the amount of communication needed to realize a choice rule, measured with the number of transmitted bits or real variables. Applications include efficiency in convex economies, exact or approximate surplus maximization in combinatorial auctions, the core in indivisible-good economies, and stable many-to-one matchings.     

Sequential communication with ex post participation constraints

This paper examines an informed principal-agent game with ex post participation constraints for the agent. It shows that the players do not lose by communicating in turn among themselves rather than simultaneously if and only if the principal communicates first. It then considers every Bayesian incentive compatible allocation rules that assign non-negative payoffs for one player in a bilateral asymmetric information framework. It provides necessary and sufficient conditions for sequential communication to be as efficient as simultaneous communication in implementing these allocation rules when the player with unbounded payoffs moves first.     

The communication requirements of efficient allocations and supporting prices

We show that any communication finding a value-maximizing allocation in a private-information economy must also discover supporting prices (in general personalized and nonlinear). In particular, to allocate L indivisible items between two agents, a price must be revealed for each of the 2^L-1 bundles. We prove that all monotonic prices for an agent must be used, hence exponential communication in L is needed. Furthermore, exponential communication is needed just to ensure a higher share of surplus than that realized by auctioning all items as a bundle, or even a higher expected surplus (for some probability distribution over valuations). When the utilities are submodular, efficiency still requires exponential communication (and fully polynomial approximation is impossible). When the items are identical, arbitrarily good approximation is obtained with exponentially less communication than exact efficiency.     

Comparative cheap talk

When are comparative statements credible? We show that simple complementarity conditions ensure that an expert with private information about multiple issues can credibly rank the issues for a decision maker. By restricting the expert's ability to exaggerate, multidimensional cheap talk of this form permits communication when it would not be credible in a single dimension. The communication gains can be substantial with even a couple of dimensions, and the complete ranking is asymptotically equivalent to full revelation as the number of issues becomes large. Nevertheless, partial rankings are sometimes more credible and/or more profitable for the expert than the complete ranking. Comparative cheap talk is robust to asymmetries that are not too large. Consequently, for sufficiently many independent issues, there are always some issues sufficiently symmetric to permit comparative cheap talk.     

An examination of the effect of messages on cooperation under double-blind and single-blind payoff procedures

Previous research has suggested that communication and especially promises increase cooperation in laboratory experiments. This has been taken as evidence for internal motivations such as guilt aversion or preference for promise keeping. The goal of this paper was to examine messages under a double-blind payoff procedure to test the alternative explanation that promise keeping is due to external influence and reputational concerns. Employing a 2×2 design, we find no evidence that communication increases the overall level of cooperation in our experiments with double-blind payoff procedures. However, we also find no evidence that communication impacts cooperation in our experiments with single-blind payoff procedures. Further, the payoff procedure does not appear to impact aggregate cooperation.     

Endogenous bid rotation in repeated auctions

I study collusion between two bidders in a general symmetric IPV repeated auction, without communication, side transfers, or public randomization. I construct a collusive scheme, endogenous bid rotation, that generates a payoff larger than the bid rotation payoff.     

Distributional preference in Japan

Using experiments developed by Engelmann and Strobel ( 2004 ), this study investigates distributional preference in Japan. We find that just over half the people in the study have a maximin preference, approximately 7 to 19% have an efficiency preference, approximately 8% have a self‐interest preference, and approximately 18% chose the allocation that would reduce the payoff to the rich and the poor, given that her/his payoff would remain constant. The last preference could be interpreted as what is referred to as “malice”, “deep envy” or a “feeling of vulnerability” in behavioural economics and cross‐cultural psychology.     

Deliberative voting

We analyze a model of jury decision making in which jurors deliberate before casting their votes. We consider a wide range of voting institutions and show that deliberations render these equivalent with respect to the sequential equilibrium outcomes they generate. In particular, in the context of a jury setup, all voting rules excluding the two types of unanimity rules (one requiring a unanimous consensus to acquit, one requiring a unanimous consensus to convict) induce the same set of equilibria outcomes. We show the robustness of our results with respect to several restrictions on communication protocols and jurors’ strategies. Furthermore, we demonstrate that our observations extend to practically all of the voting structures commonly studied in the voting literature. The paper suggests the importance of accounting for communication in models of collective choice.     

Communication, consensus and order. Who wants to speak first?

Parikh and Krasucki [R. Parikh, P. Krasucki, Communication, consensus and knowledge, J. Econ. Theory 52 (1990) 178-189] show that, in a group of rational agents, communication of the value of a function f leads to a consensus on the value of f, provided some conditions on the communication protocol and the function f hold. In this article, we address the issue of the influence of the protocol on the outcome of the communication process, when agents value information positively. We show that, if it is common knowledge in a group of agents that some of them disagree on two protocols, then the consensus value of f must be the same for both protocols.     

Herding effects in order driven markets: The rise and fall of gurus

We introduce an order driver market model with heterogeneous traders that imitate each other on a dynamic network structure. The communication structure evolves endogenously via a fitness mechanism based on agents performance. We assess under which assumptions imitation, among noise traders, can give rise to the emergence of gurus and their rise and fall in popularity over time. We study the wealth distribution of gurus, followers and non followers and show that traders have an incentive to imitate and a desire to be imitated since herding turns out to be profitable. The model is then used to study the effect that different competitive strategies (i.e. chartist & fundamentalist) have on agents performance. Our findings show that positive intelligence agents cannot invade a market populated by noise traders when herding is high.     

Communication via a strategic mediator

This paper investigates communication between an informed expert and an uninformed principal via a strategic mediator. We demonstrate that, for any bias in the parties' preferences, there exists a strategic mediator that provides the highest expected payoff to the principal, as if the players had communicated through an optimal non-strategic mediator.     

New experiments in industrial organisation

Experimental economics has devoted much of its relatively short life to the study of issues of industrial organisation, and has achieved notable successes, of considerable value to the development of both the theoretical and empirical aspects of the subject. The general message emerging from the market-level experiments is that the existence of, and convergence to, the (market) equilibrium of neoclassical theory is, in general, well-supported by the experimental evidence; on the other hand, the general message emerging from the individual level experiments is that the foundations of the neoclassical market theories are seriously flawed. This paper argues for new types of experiments in industrial organisation, ones that are theory-suggesting rather than theory-testing, and ones that are more ill-defined than those carried out to date. There is a need to shed some light on how people tackle extremely complicated ill-defined problems as opposed to experiments confined to testing well-defined theories of simple problems with complicated solutions.I am particularly grateful to the ESRC, the Leverhulme Trust and the Fondazione Ivo Vanzi for financing the experiments discussed in this paper. I would also like to pay tribute to Patrizia Sbriglia, who has carried out much of the work on The Combination Race, and to Cristina Pitassi, who has worked with me on the Oligopoly Experiment discussed at the end of the paper. Finally, my especial thanks to Norman Spivey, for writing the software for two of the three experiments discussed here, and to Jo Hall for typing this paper faster than I could write it.     

When mandatory disclosure hurts: Expert advice and conflicting interests

We study the quality of advice that an informed and biased expert gives to an uninformed decision maker. We compare two scenarios: mandatory disclosure of the bias and nondisclosure, where information about the bias can only be revealed through cheap-talk. We find that in many scenarios nondisclosure allows for higher welfare for both parties. Hiding the bias allows for more precise communication for the more biased type and, if different types are biased in different directions, may allow for the same for the less biased type. We identify contexts where equilibrium revelation allows but mandatory disclosure prevents meaningful communication.     

Winner's curse without overbidding

We report the results of a series of second-price auction experiments where each bidder's signal is given by a normally distributed value plus a normally distributed error. While bidders’ values differ in one treatment they are the same in another, which allows for a direct test of the “winner's curse” irrespective of confounding factors. Bidders may also fall prey to a “news curse” when they do not sufficiently take into account that signals and errors are correlated. We find that the effects of the winner's curse are mitigated by a news curse and loss or risk aversion.     

Communication and reputation in procurement auctions — Some empirical evidence

This paper studies communication and reputation in market interactions using data from online procurement auctions. Positive reputation ratings and engaging in communication increase a bidder’s probability of winning. Messages are primarily used to reduce the asymmetric information associated with transactions.