WEAK LINKS, GOOD SHOTS AND OTHER PUBLIC GOOD GAMES: BUILDING ON BBV

We suggest an alternative way of analyzing the canonical Bergstrom-Blume-Varian model of non-cooperative voluntary contributions to a public good that avoids the proliferation of dimensions as the number of players is increased. We exploit this approach to analyze models in which the aggregate level of public good is determined as a more general social composition function of individual gifts – specifically, as a generalized CES form – rather than as an unweighted sum as well as the weakest-link and best-shot models suggested by Hirshleifer. In each case, we characterize the set of equilibria, in some cases establishing existence of a unique equilibrium as well as briefly pointing out some interesting comparative static properties. We also study the weakest-link and best-shot limits of the CES composition function and show how the former can be used for equilibrium selection and the latter to show that equilibria of some better-shot games are identical to those of the much simpler best-shot game.non cooperative games, public goods, weakest links, best shots

Cooperation Enforcement for Packet Forwarding Optimization in Multi-hop Ad-hoc Networks

Ad-hoc networks are independent of any infrastructure. The nodes are autonomous and make their own decisions. They also have limited energy resources. Thus, a node tends to behave selfishly when it is asked to forward the packets of other nodes. Indeed, it would rather choose to reject a forwarding request in order to save its energy. To overcome this problem, the nodes need to be motivated to cooperate. To this end, we propose a self-learning repeated game framework to enforce cooperation between the nodes of a network. This framework is inspired by the concept of "The Weakest Link" TV game. Each node has a utility function whose value depends on its cooperation in forwarding packets on a route as well as the cooperation of all the nodes that form this same route. The more these nodes cooperate the higher is their utility value. This would establish a cooperative spirit within the nodes of the networks. All the nodes will then more or less equally participate to the forwarding tasks which would then eventually guarantee a more efficient packets forwarding from sources to respective destinations. Simulations are run and the results show that the proposed framework efficiently enforces nodes to cooperate and outperforms two other self-learning repeated game frameworks which we are interested in.Comment: Published in the proceedings of the IEEE Wireless Communications and Networking Conference (WCNC 2012), Paris, France, 201

AN EXPERIMENTAL ANALYSIS OF CONDITIONAL COOPERATION

Experimental and empirical evidence identifies the existence of socialpreferences and proposes competing models of such preferences. In this paper, wefurther examine one such social preference: conditional cooperation. We run threeexperimental public goods games, the traditional voluntary contribution mechanism(VCM, also called the linear public goods game), the weak-link mechanism (WLM) andthe best-shot mechanism (BSM). We then analyze the existence and types ofconditional cooperation observed. We find that participants are responsive to the pastcontributions of others in all three games, but are most responsive to differentcontributions in each game: the median in the VCM, the minimum in the WLM and themaximum in the BSM. We conclude by discussing implications of these differences forbehavior in these three mechanisms. This paper thus refines our notions of conditionalcooperation to allow for different types of public good production functions and byextension, other contexts.experimental economics, conditional cooperation, public goods

Coordination, focal points and voting in strategic situations : a natural experiment

This paper studies coordination in a multi-stage elimination tournament with large monetary incentives and a diversified subject pool drawn from the adult British population. In the tournament, members of an ad hoc team earn money by answering general knowledge questions and then eliminate one contestant by plurality voting without prior communication. We find that in the early rounds of the tournament, contestants use a focal principle and coordinate on one of the multiple Nash equilibria in pure strategies by eliminating the weakest member of the team. However, in the later rounds, contestants switch to playing a mixed strategy Nash equilibrium

Cooperation Spillovers in Coordination Games

Motivated by problems of coordination failure observed in weak-link games, we experimentally investigate behavioral spillovers for order-statistic coordination games. Subjects play the minimum- and median-effort coordination games simultaneously and sequentially. The results show the precedent for cooperative behavior spills over from the median game to the minimum game when the games are played sequentially. Moreover, spillover occurs even when group composition changes, although the effect is not as strong. We also find that the precedent for uncooperative behavior does not spill over from the minimum game to the median game. These findings suggest guidelines for increasing cooperative behavior within organizations.coordination, order-statistic games, experiments, cooperation, minimum game, behavioral spillover

Reducing Efficiency through Communication in Competitive Coordination Games

Costless pre-play communication has been found to effectively facilitate coordination and enhance efficiency by increasing individual payoffs in games with Pareto-ranked equilibria. We report an experiment in which two groups compete in a weakest-link contest by expending costly efforts. Allowing group members to communicate before choosing efforts leads to more aggressive competition and greater coordination, but also results in substantially lower payoffs than a control treatment without communication. Our experiment thus provides evidence that communication can reduce efficiency in competitive coordination games. This contrasts sharply with experimental findings from public goods and other coordination games, where communication enhances efficiency and often leads to socially optimal outcomes.Contest; Between-group Competition; Within-group Competition; Cooperation; Coordination; Free-riding; Experiments

Efficiency Gains from Team-Based Coordination: Large-Scale Experimental Evidence

The need for efficient coordination is ubiquitous in organizations and industries. The literature on the determinants of efficient coordination has focused on individual decision-making so far. In reality, however, teams often have to coordinate with other teams. We present an experiment with 825 participants, using six different coordination games, where either individuals or teams interact with each other. We find that teams coordinate much more efficiently than individuals. This finding adds one important cornerstone to the recent literature on the conditions for successful coordination. We explain the differences between individuals and teams using the experience weighted attraction learning model.coordination games, individual decision-making, team decision-making, experience-weighted attraction learning, experiment

The Core Can Be Accessed with a Bounded Number of Blocks

We show the existence of an upper bound for the number of blocks required to get from one imputation to another provided that accessibility holds. The bound depends only on the number of players in the TU game considered. For the class of games with non-empty cores this means that the core can be reached via a bounded sequence of blocks.mathematical economics;