Strategic Behavior of Moralists and Altruists,

Does altruism and morality lead to socially better outcomes in strategic interactions than selfishness? We shed some light on this complex and non-trivial issue by examining a few canonical strategic interactions played by egoists, altruists and moralists. By altruists we mean people who do not only care about their own material payoffs but also about those to others, and by a moralist we mean someone who cares about own material payoff and also about what would be his or her material payoff if others were to act like himself or herself. It turns out that both altruism and morality may improve or worsen equilibrium outcomes, depending on the nature of the game. Not surprisingly, both altruism and morality improve the outcomes in standard public goods games. In infinitely repeated games, however, both altruism and morality may diminish the prospects of cooperation, and to different degrees. In coordination games, morality can eliminate socially inefficient equilibria while altruism cannot

The Evolution of Collaboration in Symmetric 2x2-Games with Imperfect Recognition of Types

A recent series of papers has introduced a fresh perspective on the problem of the evolution of human cooperation by suggesting an amendment to the concept of cooperation itself: instead of thinking of cooperation as playing a particular strategy in a given game, usually C in the prisoner's dilemma, we could also think of cooperation as collaboration, i.e. as coalitional strategy choice, such as jointly switching from (D;D) to (C;C). The present paper complements previous work on collaboration by expanding on its genericity while relaxing the assumption that collaborators are able to perfectly identify their own kind. Conditions for the evolutionary viability of such collaboration under fairly undemanding assumptions about population and interaction structure are derived. Doing so, this paper shows that collaboration is an adaptive principle of strategy choice in a broad range of niches, i.e., stochastic mixtures of games

Estimating Social Preferences and Kantian Morality in Strategic Interactions

Recent theoretical work suggests that a form of Kantian morality has evolutionary foundations. To investigate the relative importance of Kantian morality and social preferences, we run laboratory experiments on strategic interaction in social dilemmas. Using a structural model, we estimate social preferences and morality concerns both at the individual level and the aggregate level. We observe considerable heterogeneity in social preferences and Kantian morality. A finite mixture analysis shows that the subject pool is well described as consisting of two types. One exhibits a combination of inequity aversion and Kantian morality, while the other combines spite and Kantian morality

Essais dans les situations de contract avec préférences prosociales

Le résumé en français n'a pas été communiqué par l'auteur.Le résumé en anglais n'a pas été communiqué par l'auteur

Estimating Social Preferences and Kantian Morality in Strategic Interactions

Recent theoretical work suggests that a form of Kantian morality has evolutionary foundations. To investigate the relative importance of Kantian morality and social preferences, we run laboratory experiments on strategic interaction in social dilemmas. Using a structural model, we estimate social preferences and morality concerns both at the individual level and the aggregate level. We observe considerable heterogeneity in social preferences and Kantian morality. A finite mixture analysis shows that the subject pool is well described as consisting of two types. One exhibits a combination of inequity aversion and Kantian morality, while the other combines spite and Kantian morality

Exploring the diversity of social preferences: Is a heterogeneous population evolutionarily stable under assortative matching?

Why do individuals make different decisions when confronted with similar choices? This paper investigates whether the answer lies in an evolutionary process. Our analysis builds on recent work in evolutionary game theory showing the superiority of a given type of preferences, homo moralis, in fitness games with assortative matching. We adapt the classical definition of evolutionary stability to the case where individuals with distinct preferences in a population coexist. This approach allows us to establish the characteristics of an evolutionarily stable population. Then, introducing an assortment matrix for assortatively matched interactions, we prove the existence of a heterogeneous evolutionarily stable population in 2x2 symmetric fitness games under constant assortment, and we identify the conditions for its existence. Conversely to the classical setting, we find that the favored preferences in a heterogeneous evolutionarily stable population are context-dependent. As an illustration, we discuss when and how an evolutionarily stable population made of both selfish and moral individuals exists in a prisoner's dilemma. These findings offer a theoretical foundation for the empirically observed diversity of preferences among individuals

Three essays on social institutions and individual behavior

This thesis studies the interactions between individual behavior and social institutions. The first chapter proposes a model of equilibrium switching in games with mul tiple strict Nash equilibria such as the evolution of social conventions. In our model, players are forward-looking but use level-k reasoning about their peers’ choices. We find that equilibrium switching is deterministic and gradual, with higher k players switching first. In some cases, the final equilibrium is reached only after several other equilibria are visited, where each step is Pareto improving. We completely characterize the switching paths for all games with finite strict Nash equilibria, and a large class of level-k populations. The model provides a unified explanation for puzzling equilibrium switching results reported in recent experimental studies, including the direction of transition, asynchronous participation, and alternations between strict Nash equilibria. The second chapter empirically tests a theory of equilibrium transition among strict Nash equilibria, the sampling best response dynamic that predicts equilibrium transitions under inexact (inaccurate but unbiased) information of opponents’ behaviors. We design a quasi-continuous-time experiment in which a group of subjects plays a coordination game recurrently under either more or less accurate information. We observe that more accurate information facilitates efficiency-improving transitions among strict Nash equilibria than less accurate information, which is in contrast with the evolutionary theory but supports the models of strategic teaching. More accurate information about opponents’ behaviors induces more subjects to engage in persistent strategic deviations from inefficient Nash equilibria that can induce more subjects to deviate in the future, resulting in efficiency-improving equilibrium transitions. When information is less accurate, subjects’ choices are less responsive to changes in the information received. The slow response to the information either blocks or delays efficiency-improving equilibrium transitions. The third chapter investigates the optimal fertility strategy and its impact on the fertility rate and parental investment under patriarchal institutions. We show that the optimal fertility strategy is a one-stage look-ahead strategy and represents a son-preferring stopping rule if there is a patriarchal institution in favor of sons over daughters. We further characterize the resulting demographic distribution of the possible sex combinations of children in a family. It suggests that, under the optimal fertility strategy, females are disproportionately born into larger families, and therefore receive lower average investment than males. In addition, both under and over-reproduction exist in a patriarchal society, but the average fertility rate can be lower than in a gender-neutral society

Strategic Behavior of Moralists and Altruists

Does altruism and morality lead to socially better outcomes in strategic interactions than selfishness? We shed some light on this complex and non-trivial issue by examining a few canonical strategic interactions played by egoists, altruists and moralists. By altruists, we mean people who do not only care about their own material payoffs but also about those to others, and, by a moralist, we mean someone who cares about own material payoff and also about what would be his or her material payoff if others were to act like himself or herself. It turns out that both altruism and morality may improve or worsen equilibrium outcomes, depending on the nature of the game. Not surprisingly, both altruism and morality improve the outcomes in standard public goods games. In infinitely repeated games, however, both altruism and morality may diminish the prospects of cooperation, and to different degrees. In coordination games, morality can eliminate socially inefficient equilibria while altruism cannot