Signaling and Tacit Collusion in an Infinitely Repeated Prisoners' Dilemma

In the context of an infinitely repeated Prisoners.Dilemma, we explore how cooperation is initiated when players signal and coordinate through their actions. There are two types of players - patient and impatient - and a player's type is private information. An impatient type is incapable of cooperative play, while if both players are patient types - and this is common knowledge - then they can cooperate with a grim trigger strategy. We find that the longer that players have gone without cooperating, the lower is the probability that they'll cooperate in the next period. While the probability of cooperation emerging is always positive, there is a positive probability that cooperation never occurs.

Quality-Ensuring Profits

In the reputation model of Klein and Leffler (1981) firms refrain from cutting quality or price because if they did they would forfeit future profits. Something similar can happen even in a static setting. First, if there exist some discerning consumers who can observe quality, firms wish to retain their purchases. Second, if all consumers can sometimes but not always spot flaws, firms do not want to lose the business of those who would spot them on a given visit. Third, if the law provides a penalty for fraud, but not one so high as to to make fraud unprofitable, firms may prefer selling high quality at high prices to low quality at high prices plus some chance of punishment.reputation, product quality, moral hazard, quality-guaranteeing price

A tree formulation for signaling games

We provide a detailed presentation and complete analysis of the sender/receiver Lewis signaling game using a game theory extensive form, decision tree formulation. The analysis employs well established game theory ideas and concepts. We establish the existence of four perfect Bayesian equilibria in this game. We explain which equilibrium is the most likely to prevail. Our explanation provides an essential step for understanding the formation of a language convention. Further, we discuss the informational content of such signals and calibrate a more detailed definition of a true (“correct”) signal in terms of the payoffs of the sender and the receiver

Signaling and Tacit Collusion in an Infinitely Repeated Prisoners' Dilemma

In the context of an infinitely repeated Prisoners' Dilemma, we explore how cooperation is initiated when players signal and coordinate through their actions. There are two types of players - patient and impatient - and a player's type is private information. An impatient type is incapable of cooperative play, while if both players are patient types - and this is common knowledge - then they can cooperate with a grim trigger strategy. We find that the longer that players have gone without cooperating, the lower is the probability that they'll cooperate in the next period. While the probability of cooperation emerging is always positive, there is a positive probability that cooperation never occurs.

Private Monitoring in Auctions

We study collusion in repeated first-price auctions under the condition of minimal information release by the auctioneer. In each auction a bidder only learns whether or not he won the object. Bidders do not observe other bidders’ bids, who participates or who wins in case they are not the winner. We show that for large enough discount factors collusion can nevertheless be supported in the infinitely repeated game. While there is a unique Nash equilibrium in public strategies, in which bidders bid competitively in every period, there are simple Nash equilibria in private strategies that support bid rotation. Equilibria that either improve on bid rotation or satisfy the requirement of Bayesian perfection, but not both, are only slightly more complex. Our main result is the construction of perfect Bayesian equilibria that improve on bid rotation. These equilibria require complicated inferences off the equilibrium path. A deviator may not know who has observed his deviation and consequently may have an incentive to use strategic experimentation to learn about the bidding behavior of his rivals. ZUSAMMENFASSUNG - (Privates Monitoring in Auktionen) Der Beitrag untersucht, inwieweit Bieter Kollusion, bzw. stillschweigende Abkommen, in wiederholten Erstpreisauktionen aufrecht erhalten können, in welchen der Auktionator alle Informationen zurückhält. Nach jeder Auktion lernt ein Bieter nur, ob er das Objekt gewonnen hat oder nicht. Ein Bieter kann weder die Gebote der anderen Bieter beobachten, noch kann er beobachten, welche Bieter an der Auktion teilgenommen haben und wer gewonnen hat - solange er nicht selbst das Objekt erhält. Wir zeigen, dass in dem unendlich wiederholten Spiel für hinreichend geduldige Bieter Kollusion möglich ist. Es existiert zwar ein eindeutiges Gleichgewicht in öffentlichen Strategien, in welchem die Bieter in jeder Periode kompetitiv bieten, aber es gibt einfache Nash-Gleichgewichte in privaten Strategien, die Bieterrotation durchsetzen. Wir zeigen auch, dass Bieterrotation das Ergebnis eines perfekt bayesianischen Gleichgewichtes sein kann. Nash-Gleichgewichte, die höhere erwartete Gewinne als Bieterrotation erzielen, sind nur ein wenig komplexer. Das Hauptergebnis ist die Konstruktion von (essentiell) perfekt bayesianischen Gleichgewichten, welche höhere Gewinne als Bieterrotation erzielen. Nach Abweichungen vom Gleichgewichtspfad, müssen die Bieter in diesen Gleichgewichten komplizierte Rückschlüsse auf das Verhalten Ihrer Wettbewerber ziehen. So weiß ein Bieter nach bestimmten Abweichungen nicht, ob diese von seinen Mitspielern beobachtet wurden, und hat ein Interesse daran, durch strategisches experimentieren das Bietverhalten seiner Rivalen kennenzulernen.Itacit collusion, repeated auctions, supergames, contagion, bid-rotation, trigger strategies.

The Implications of Pricing on Social Learning

We study the implications of endogenous pricing for learning and welfare in the classic herding model . When prices are determined exogenously, it is known that learning occurs if and only if signals are unbounded. By contrast, we show that learning can occur when signals are bounded as long as non-conformism among consumers is scarce. More formally, learning happens if and only if signals exhibit the vanishing likelihood property introduced bellow. We discuss the implications of our results for potential market failure in the context of Schumpeterian growth with uncertainty over the value of innovations