ABSTRACT
This chapter summarizes the theoretical guidelines and the empirical basis for a multifaceted research program requiring a combination of psychological and sociological procedures. The individuals studied in the research program are adolescents. From the properties of groups and heir formation, several hypotheses about member attitudes and behaviour were deduced. The major hypotheses of the research program and a string of auxiliary predictions are spelled out in Reference Groups. In social science and psychology, there are grand theories of the individual-group-society relationship. The indiscriminate use of models based on analogy with other sciences has proceeded with a singular lack of concern for the crucial question of the isomorphism between the models, and the events and actualities of which they are supposed to be models. From studies of both small and large organizations human groups have properties more complex than merely an undifferentiated state of interdependence among individuals.