This study investigated the role of one factor in the dramatic conformity reduction produced by a partner who agrees with S in the face of group pressure--the independent assessment of social and physical reality provided by the partner. Two social support conditions, varying only in S's perception of the partner's adequacy as a valid reference for making judgments, were created. A unanimous group was also included to provide a conformity baseline. Results indicated that conformity was significantly reduced in both social support conditions; moreover, the valid social supporter produced a significantly greater decrease in conformity than did the invalid partner. The data support the hypothesis that independent assessment of reality provided by a partner is crucial to the efficacy of social support in reducing conformity. (Author)