Dated from the sixties, the research field of adjunctive behavior is extensive and controversial. This review presents an analysis of the main theoretical interpretations of the phenomenon, and demonstrates that many of the features considered to be characteristic of adjunctive behavior are also present in non adjunctive behavior. Falk has interpreted adjunctive behavior as displaced activity, Staddon as schedule-induced behavior, Timberlake as a part of a pre-programmed behavioral system, and Wetherington has called into question the existence of a third class of behavior. It is concluded that all theoretical approaches appear to be incomplete due to the diversity of adjunctive behavior topographies and to their dependence on species and environmental variables, besides schedule parameters.
adjunctive behavior; polydipsia; schedule-induced behavior; non contingent stimulus