Intergroup discrimination in the minimal group paradigm: categorization, reciprocation, or fear?

H. Tajfel's (1970) minimal group paradigm (MGP) research suggests that social categorization is a sufficient antecedent of ingroup-favoring discrimination. Two experiments examined whether discrimination in the MGP arises from categorization or processes of outcome dependence, that is, ingroup reciprocity and outgroup fear. Experiment 1 unconfounded categorization from outcome dependence. Categorized men discriminated only when dependent on others. Categorized women discriminated regardless of the structure of dependence. Experiment 2 examined dependence on the ingroup versus the outgroup as the locus of male-initiated discrimination. Consistently with an ingroup reciprocity effect, men discriminated when dependent on ingroup, but not outgroup, members. Sex differences are discussed in regard to women's heightened ingroup dependence produced by biological or environmental constraints.