Being uncertain about what? Procedural fairness effects as a function of general uncertainty and belongingness uncertainty

Do different forms of uncertainty account for different procedural fairness effects? We hypothesized that general uncertainty accounts for fairness judgments, whereas belongingness uncertainty accounts for group identification. Experiment 1 manipulated general versus belongingness uncertainty. Participants in the general uncertainty condition regarded the procedures as fairer when they were granted than denied voice, whereas participants in the belongingness uncertainty condition showed stronger group identification when they were granted than denied voice. Experiment 2 split the belongingness uncertainty condition into family and stranger uncertainty. Only participants in the family-belongingness uncertainty condition identified with their group when they were granted than denied voice. The findings have implications for the construct of uncertainty, models of procedural fairness, and group membership.