The relationship between personality and overt behavior, particularly as it applies to social interaction, is of considerable significance in personality theory, social psychology, and in the application of group psychotherapy. Despite the importance of this relationship, the fields of group therapy and group dynamics have until now largely ignored this issue. Leadership, conformity behavior, sociometric choice, and problem solving in groups have been the main themes of research carried out in the area of group dynamics. These studies have generally concentrated on situational variables rather than on personality differences and have dealt with experimenter manipulated groups rather than with free-flowing or nonsystematically-manipulated groups. In group psychotherapy experimentally defined studies have been sparse; the majority of them have dwelled on changes during the course of therapy in which a variety of procedures have been employed to evaluate the personality of group members.4,9,11,18 These studies, however, have