ABSTRACT
The dominant approaches to development covered a broad range of theoretical possibilities, but scarcely ever referred to the specific details of behavioral development in real animals. The essential model presupposed a passive organism whose development was shaped by the interdependent relations between stimuli, responses, and reinforcements, which were thought of as the critical elements producing behavioral change. The model views development from the standpoint of two major adaptive problems or ”tasks, ” that the developing primate confronts, each characterized by a distinct developmental trend. One task is to make an effective adjustment to the maternal niche, and the other is to respond effectively to the demands and opportunities of the nonmaternal environment The trends relating to each of these tasks appear early in ontogeny, follow different developmental trajectories, and are present throughout life. They lay down the principal functional dimensions along which preadult psychological development proceeds.
