ABSTRACT
The historically correct definition of epigenesis-the emergence of new structures and functions during the course of individual development-did not specify, even in a general way, how these emergent properties come into existence. Thus, there was still room for preformation-like thinking about development, which I (Gottlieb, 1970) earlier labeled the predetermined conception of epigenesis, in contrast to a probabilistic conception (see Table 13-1 for details). That epigenetic development is probabilistically determined by active interactions among its constituent parts is now so well accepted that epigenesis itself is sometimes defined as the interactionist approach to the study of individual development (e.g., Dewsbury, 1978; Johnston, 1987). That is a fitting tribute to the career-long labors of Zing-Yang Kuo (1976), T.C.Schneirla (1961), and Daniel S.Lehrman (1970), the principal champions of the interaction idea in the field of psychology, particularly as it applies to the study of behavioral and psychological development.
