“…Conceptual differentiation in categorizing can be conceived of as an aspect of cognitive complexity. It is therefore necessary to consider relations between this dimension of individual consistencies and that inferred from responses to the role construct repertory tests developed on the basis of Kelly's (1955) work and used by a number of investigators to assess cognitive "complexity-simplicity" (see, e.g., Bieri, 1955;Bieri & Blacker, 1956a, 1956bBieri & Messerley, 1957;Dopp, 1960;Leventhal, McGaughran, & Moran, 1959;Lundy & Berkowitz, 1957). Kelly (1955) emphasizes the importance of contrast in concept formation.…”