Research

Dissertation Chapters



Recent work in behavioral economics has suggested that individuals derive utility from the beliefs that they hold. More specifically, individuals are assumed to be motivated to improve their self-image. In order to maintain a positive self-image, their behavior needs to be consistent with the beliefs they have about themselves, which leads to self-signaling. The objective of this paper is to reevaluate the idea that (i) individuals care about their self-image, and (ii) individuals self-signal. I first argue that the desired self-image is best seen as the desired reputation. Then, I defend the idea that what appears to be self-signaling in the laboratory reflects the workings of a psychology well-adapted to the social incentives of everyday life, which spillovers when individuals find themselves in new, contrived environments.


In this paper, I argue that the theory of social evolution has the necessary scope and power to provide a useful theoretical framework for human social preferences. Social evolution theory applies to any social interaction and makes sharp predictions about the kinds of social traits that can be observed in the population. It illuminates the function of our social emotions, which are context-dependent, endogenous mechanisms that modulate our social relationships with others. I discuss two mechanisms that underlie the wide variation in the expression of social preferences: social norms (or institutions) and local ecology. The wealth of findings on human social preferences supports their context-dependent nature and prompts us to investigate the incentives underlying their expression.


This paper proposes a theory of social identity adoption and expression, which ties the choice of social identity to material and social benefits present in an individual's social environment. I argue that in an environment in which receivers aim at uncovering the sender's motives and commitments, the beliefs and values adopted by an individual can serve as a signal of trustworthiness. In such an environment, individuals are expected to adopt the social identity which will provide them with the greatest amount of (social) benefits. I formalize this choice in a game-theoretic framework, embed in a broader niche selection structure. I argue that the main predictions of the model help illuminate several empirical findings, such as the malleability of beliefs and values, the resistance of beliefs and values to evidence, and the existing correlation between beliefs and values and individual-level traits such as personality.


The objective of this paper is to investigate whether positive illusions can persuade at equilibrium. In a two-player "Partner Choice" game, I show that "Low" types can pool with "High" types by adopting positive illusions. The equilibrium size of the illusion is predicted to be sensitive to the reputational costs of lying and the degree of observability of the Sender's underlying quality. In a three-player "Community" game, I show that positive illusions can remain stable provided that the equilibrium size of the lie is small enough, providing enough plausible deniability to the Sender. In both models, positive illusions are stable at equilibrium, even though Receivers correctly anticipate the average value of the Sender's type. The empirical literature on positive illusions appears to support the main predictions of both models.


The concept of Individually-Consistent-Sequential-Equilibrium broadens the concept of Sequential Equilibrium by allowing players to have different beliefs on potential deviations. This heterogeneity spontaneously gives rise to a notion of distance between beliefs. Yet, studying distance between beliefs in a strategic context reveals to be intricate. Announced beliefs may be different from revealed beliefs, and the meaning of distance depends on the role assigned to beliefs. If out-of-equilibrium beliefs help getting a larger payoff at equilibrium, then we might need to reconsider the traditional definition of sequential rationality: more than just requiring that players behave optimally at every information set given their beliefs and the strategies played by others players, we might additionally require that there does not exist another perturbation scheme that is individually-consistent and which provides higher payoffs to the players.