Communication and Bargaining in the Spatial Model

This paper studies collective choice by participants possessing private information about the consequences of policy decisions in policymaking institutions that involve cheap-talk communication and bargaining. The main result establishes a connection between the extent to which problems of this type posses fully-revealing equilibria that select policies in the full information majority rule core (when it is well-defined) and the extent to which a fictitious sender-receiver game possesses a fully revealing equilibria. This result allows us to extend Banks and Duggan's (2000) core equivalence results to the case of noisy policymaking environments with private information when some combination of nonexclusivity and preference alignment conditions are satisfied.

Signaling and Countersignaling: A Theory of Understatement

In signaling environments ranging from consumption to education, high quality senders often shun the standard signals that should separate them from lower quality senders. We find that allowing for additional, noisy information on sender quality permits equilibria where medium types signal to separate themselves from low types, but high types then choose to not signal or countersignal. High types not only save costs by relying on the additional information to stochastically separate them from low types, but countersignaling itself is a signal of confidence which separates high types from medium types. Experimental results confirm that subjects can learn to countersignal.signaling; countersignaling; understatement

Essays in Economic Theory: Strategic Communication and Information Design

This dissertation consists of four essays in economic theory. All of them fall under the umbrella of economics of information; we study various models of game-theoretic interaction between players who are communicating with others, and have (or are able to produce) information of some sort. There is a large emphasis on the interplay of information, incentives and beliefs. In the first chapter we study a model of communication and persuasion between a sender who is privately informed and has state independent preferences, and a receiver who has preferences that depend on the unknown state. In a model with two states of the world, over the interesting range of parameters, the equilibria can be pooling or separating, but a particular novel refinement forces the pooling to be on the most informative information structure in interesting cases. We also study two extensions - a model with more information structures as well as a model where the state of the world is non-dichotomous, and show that analogous results emerge. In the second chapter, which is coauthored with Joseph E. Stiglitz and Jungyoll Yun, we study the Rothschild-Stiglitz model of competitive insurance markets with endogenous information disclosure by both firms and consumers. We show that an equilibrium always exists, (even without the single crossing property), and characterize the unique equilibrium allocation. With two types of consumers the outcome is particularly simple, consisting of a pooling allocation which maximizes the well-being of the low risk individual (along the zero profit pooling line) plus a supplemental (undisclosed and nonexclusive) contract that brings the high risk individual to full insurance (at his own odds). We also show that this outcome is extremely robust and Pareto efficient. In the third chapter we study a game of strategic information design between a sender, who chooses state-dependent information structures, a mediator who can then garble the signals generated from these structures, and a receiver who takes an action after observing the signal generated by the first two players. Among the results is a novel (and complete, in a special case) characterization of the set of posterior beliefs that are achievable given a fixed garbling. We characterize a simple sufficient condition for the unique equilibrium to be uninformative, and provide comparative statics with regard to the mediator’s preferences, the number of mediators, and different informational arrangements. In the fourth chapter we study a novel equilibrium refinement - belief-payoff monotonicity. We introduce a definition, argue that it is reasonable since it captures an attractive intuition, relate the refinement to others in the literature and study some of the properties

Conflicts of Interest and Credible Information Provision by Specialized and One-Stop Banks

This paper is concerned with the general question of the provision of information by financial intermediaries to their customers. Specifically, it analyzes the different ways the market can be organized and its effects on pricing and the level of information investors obtain. We find that market structure depends on on the reputation costs, switching costs for customers, and the existence of market power. This provides a new justification for the presence of one-stop banks. We demonstrate these findings by embedding signaling within a model of multi-product price competition.One-stop Bank, Information Provision, Signaling

Ordinal Cheap Talk

Can comparative statements be credible even when absolute statements are not? For instance, can a professor credibly rank different students for a prospective employer even if she has an incentive to exaggerate the merits of each student? Or can an analyst credibly rank different stocks even if the client would be dubious about a recommendation to buy any one of them? We examine such problems in a multidimensional sender-receiver game where the sender has private information about multiple variables. We show that ordinal cheap talk, in which the variables are completely ordered by value or grouped into categories by value, can be credible even when interests are too opposed to support communication along any single dimension. Ordinal cheap talk is credible because it reveals both favorable and unfavorable information at the same time, thereby precluding any possibility of exaggeration. The communication gains from ordinal cheap talk can be substantial with only a couple of dimensions, and the payoffs from a complete ordering are asymptotically equivalent to full revelation as the number of variables becomes large. However, in various circumstances the sender can do better through a partial ordering that categorizes variables. Compared to other forms of cheap talk, ordinal cheap talk is exceedingly simple in that the sender only makes straightforward, comparative statements.cheap talk; credibility; communication

Human-Agent Decision-making: Combining Theory and Practice

Extensive work has been conducted both in game theory and logic to model strategic interaction. An important question is whether we can use these theories to design agents for interacting with people? On the one hand, they provide a formal design specification for agent strategies. On the other hand, people do not necessarily adhere to playing in accordance with these strategies, and their behavior is affected by a multitude of social and psychological factors. In this paper we will consider the question of whether strategies implied by theories of strategic behavior can be used by automated agents that interact proficiently with people. We will focus on automated agents that we built that need to interact with people in two negotiation settings: bargaining and deliberation. For bargaining we will study game-theory based equilibrium agents and for argumentation we will discuss logic-based argumentation theory. We will also consider security games and persuasion games and will discuss the benefits of using equilibrium based agents.Comment: In Proceedings TARK 2015, arXiv:1606.0729

Optimal signaling with cheap talk and money burning

We study Sender-optimal signaling equilibria with cheap talk and money-burning. Under general assumptions, the Sender never uses money-burning to reveal all states, but always wants to garble information for at least some states. With quadratic preferences and any log-concave density of the states, optimal communication is garbled for all states: money-burning, if used at all, is used to adjust pooling intervals. This is illustrated by studying in depth the well-known uniform-quadratic case. We also show how the presence of a cost of being “caught unprepared” that gives rise to a small change in a common assumption on the Receiver’s utility function makes full revelation through money-burning Sender-optimal

Essays on two-dimensional signaling games

This dissertation studies various two-dimensional signaling games. It introduces and uses equilibrium refinements to analyze such games. In Chapters 2 and 3 of the dissertation, (one-sender) two-audience costly signaling games are studied. Chapter 2 introduces two equilibrium refinements for a class of two-audience private signaling games. Chapter 3 studies a costly gift-giving game with two audiences and investigates how observability of gifts affects pro-social behavior. Chapter 4 studies a costly persuasion game with uncertain intentions of the sender and investigates how truthful information sharing is affected by the intentions of the sender