ABSTRACT
Change and, especially, developmental change is difficult to study empirically. Methods used to study developmental change are predicated on theoretical specification of the nature of development and on the assumptions one derives from theory about: (a) units of analysis (e.g., individual-psychological variables or relations between variables from different levels of analysis, (b) levels of organization involved in developmental change (e.g., genes, organism, social relationships, or culture), and (c) the role of time and temporality (history) in indexing such change (Baltes, Reese, & Nesselroade, 1977). In other words, developmental theories vary in regard to the units of analysis and the levels of organization used to study people across time. This variation is linked to differences in the approach to research taken by scholars following different theories of development. It is useful to illustrate this linkage between theory and research.
