Abstract
The concepts of field dependence and psychological differentiation have provided an extremely valuable link between theories of personality and psychopathology and laboratory research on perception and cognition. However, confusion between test and construct and failure to control adequately for intelligence have made it difficult to assess the limits of the concept of differentiation. Further, basic understanding of the nature of the individual differences observed has been hampered by insufficient efforts to distinguish between personality differences stemming from differences in ability and those stemming from differences in adaptive choices and strategies. The present paper examines these issues as they are reflected in the current literature and attempts to point toward a more comprehensive approach to research in this area.