Abstract
The early functional value of behavior in the emergency of adjunctive behavior. From the Falk's works (1961) about adjunctive behavior, the fact that some behavioral problems in humans, -especially the compulsive behavior-, could be explained by this kind of behavior is considered. The works that study the emergency of adjunctive behavior in humans has been focused mainly in studying this behavior as á function of the topography of the response and the interreinforcement interval lenght. In this paper, an experimental work based on group desing that researchs the role that plays the early functional value that a behavior has had in the subject's behavioral story in the emergency of that behavior as adjunctive behavior is presented.