In this article, I review recent work from comparative psychology, highlighting several conceptual and methodological insights drawn from comparative research and exploring their value to an ecological approach to behavioral development. In particular, I consider examples of a major focus of comparative psychology, the search for developmental mechanisms and processes underlying the expression of species-typical behavior. This focus has provided several insights regarding behavioral development that have supported an ecological approach and provided a richness and depth of perspective on behavior complementary to that found in ecological psychology. Specifically, I review the related notions of probabilism, equifinality, nonlinearity, and distributed control and discuss their applicability to and support of ecological theory.Although the importance of context or milieu has been acknowledged in the behavioral sciences for many years (e.g, Brunswik, 1952;Kuo, 1967;Lewin, 1931;Schneirla, 1957;Werner, 1957), a concerted effort to include contextual factors in analytic studies of behavioral development is a relatively recent direction in psychological sciences (see Michel & Moore, 1995). This effort is part and parcel of the growing influence of an ecological approach to behavioral organization. As recently reviewed by Reed (1996), an ecological approach to behavior is a powerful addition to traditional psychological inquiry, in that it expands the scope of investigation and directs research attention beyond the boundary of the organism. In particular, an ecological approach views the relation between the organism and its environment, rather than the nature of the organism itself, as the appropriate object of study of psychology (J. or milieu is a major shift in research emphasis, as the science of psychology has tended to reduce the habitats or contexts of animals to "stimuli," making little attempt to examine the complex places and events within which normal behavioral development takes place (Reed, 1996). In contrast, an ecological approach views behavioral development as situated and stresses the fundamental connectedness of the organism to its surroundings. From this view, an organism's functional environment is structured, organized, and specific to the organism, and the task of defining the relevant features of an organism's context becomes an empirical problem that requires systematic description and analysis (Johnston, 1981(Johnston, , 1985.Approaching behavioral development as a process that is situated highlights the need to specify in detail the variety of physical, biological, and social factors that the organism encounters as it develops over time. Of course, as an organism develops, its relation to the external world also changes, so that its effective environment changes as well (Johnston, 1985). One of the strengths of an ecological approach to behavioral development is its explicit attempt to elaborate an appropriately dynamic view of the changing relationship between the developing organism and its ...