Individuals are members of a 'generation' by virtue of the fact that they are 'in a position to experience the same events and data', especially if the experiences impinge upon a similarly 'stratified' consciousness. By similarly 'stratified' Mannheim means having had similar experiences during the course of development. There is a continuous shift in objective conditions and a continuous shift due to the appearance of new generations. New impulses originate in new organisms and are modulated by reciprocal influences with older generations. A 'generation style' may appear as a 'realization of potentialities' if triggered by the social and cultural process. 'It must be admitted that biological data constitute the most basic stratum of factors determining generation phenomena; but for this very reason, we cannot observe the effect of biological factors directly; we must, instead, see how they are reflected through the medium of social and cultural forces.'