The Role of Interpersonal Uncertainty in Prosocial Behavior

Abstract

In prosocial decisions, decision-makers face interpersonal uncertainty–uncertainty about how their choices impact others’ utility. We show theoretically and demonstrate empirically how interpersonal uncertainty shapes behavior across key paradigms in the social preference literature. We hypothesize a two-part mechanism: individuals are averse to interpersonal uncertainty, and they experience different interpersonal uncertainty for different people. We use three approaches to show how this mechanism influences prosocial behavior. First, we compare standard allocation decisions, such as dictator games, with decisions where we remove social consequences but retain uncertainty, revealing strikingly similar patterns. Second, we experimentally vary interpersonal uncertainty to disentangle and quantify its contribution relative to social preferences in prosocial decisions, which we estimate to be of similar importance. Finally, we show that self-reported interpersonal uncertainty systematically predicts behavior across individuals, allocation patterns, and interventions that increase charitable giving.