Illegitimate group membership and inter‐group differentiation

Those who gain membership of a group by deceit, evading the norms, rules or laws which mark the group boundary, are illegitimate group members. The impact of illegitimate membership upon the tendency to engage in inter‐group differentiation was examined. It was predicted that subjects experiencing incompatibility between the internal and the external criteria of group membership, generated by their illegal entry, would in their attempts at resolution, engage in a redefinition of group structures and inter‐group relations ‐ evidenced primarily in the accentuation of discrimination against the outgroup on all dimensions of differentiation available even when these dimensions are irrelevant to the original groupings. These predictions were confirmed.