Ethnic markers and the emergence of group-specific norms

Observable social traits influence social interactions even in globalized societies. A popular hypothesis posits that such traits (ethnic markers) help promote cooperation, but an alternative explanation is that they facilitate coordination. The paper explores this latter possibility by presenting a model that investigates ethnic markers in coordination games, testing reinforcement learning as the microscopic mechanism agents use to update strategies. Across wide parameter ranges, a collective equilibrium emerges in which markers assort interactions; however, if individuals are too conformist (low aspiration) or too greedy (high aspiration), markers fail to shape interactions. These results extend prior imitation-based work and show reinforcement learning is a strong candidate to explain instances where ethnic markers influence coordination.