Leeuwen, E. van

group identification effect performance fication identi member psychology identi fication participant merger identity ingroup bias study group members ingroup expectation interaction condition contribution prosocial journal representation cooperation hypothesis research personality dilemmas proself group identity group goal cremer other level manipulation sense analysis continuation goal-transformation hypothesis knippenberg value orientation outcome van vugt orientation relationship group identi fication value measure identi fication manipulation turner brewer erasmus univ rotterdam people identi fication effect group identification result process van knippenberg goal-transformation women group performance behavior dilemma superordinate theory effort leeuwen situation interest point change identification manipulation self-interest perception van dijk identification effect decision group identities university gender