AbstractA multitude of scientific disciplines study the development of behavior. Their use of different methodological and conceptual approaches makes integration of findings difficult. In a symposium at the 38th Annual Meeting of the International Society for Developmental Psychobiology in Washington DC, the question was discussed if a general theory of development could unify the field. The three participants explain their views and discuss the possibility of a theoretical framework for development. © 2006 Wiley Periodicals, Inc. Dev Psychobiol 49: 77–86, 2007.