In-group favoritism in intergroup conflicts – GROUP

Humans are group-living species. We evolved in hunter-gatherer groups for tens of thousands of years during the Paleolithic era. Today, humans belong to various groups, identified by their gender, relatedness, social class, ethnicity, religion, or nationality. Living in groups since the pre-historic times have shaped the human psyche to discriminate between people belonging to our own group – “in-group members” – and people belonging to other groups – “out-group members”. Understanding the complex linkage between group-identity, individual preferences, and behaviors toward “in-group” and “out-group” members is at the heart of this project.
A group can be defined by characteristics that can be considered structural or objective like those mentioned above for describing groups of modern societies. A group can also be defined based on more subjective aspects like identifying oneself as a member of a specific group, and be recognized as such by the others. In this respect, the social identity theory in social psychology, emphasize that people make sharp distinction between “us” and “them”, even when groups are not formed according to some intrinsic characteristics, but by random assignment. Numerous experiments in psychology, economics, or political science, are based on what is called the “minimal-group paradigm” in which participants are assigned to groups according to an artificial attribute (such as a color code). It is generally concluded that subjects behave overly cooperative within groups. Whilst experimental research on in-group favoritism in intergroup conflicts is now well developed, this is not the case for theoretical research in social sciences. A major objective of the GROUP project is therefore to study, from a theoretical point of view, the nature and evolution of social preferences reflecting a group identity in intergroup conflicts. This, in turn, may help to conduct more focused experimental studies of in-group behavior in intergroup conflict, which has been called the “problem of the century” by social psychologists. Our approach is mainly based on state-of-the-art mathematical models and evolutionary game theory used in economics and in biology, and on controlled experiments.
The project is divided in three work packages. In the first work package, we re-examine the literature on the economics of conflict between groups in the light of behavioral economics by considering that people have biased perceptions or other-regarding preferences. The next step is to determine if it is possible to rationalize the emergence and persistence of this type of preferences in inter-group conflicts. The objective of work package 2 is then to investigate the evolutionary foundations of certain class of other-regarding preferences by using the indirect evolutionary approach. That is, evolution does not play directly at the level of strategies, or behaviors, as in standard evolutionary game theory, but indirectly at the level of preferences, which determine players’ actions and, in turn, individual fitness. Finally, work package 3 is devoted to and experimental investigation of behaviors and preferences in intergroup conflicts. The first objective is to disentangle the (potentially contradictory) theoretical predictions of homo economicus behaviors and behaviors induced by evolutionarily stable preferences. Second, the evolutionary models suppose some convergence towards evolutionary stable states. Properly designed experiments on long term interactions between opposing groups, can inform us both about the dynamics of a population structured in groups, and about a possible convergence towards a steady state, for which preferences are stabilized.