In a previous issue of "The Behavior Analyst," the authors discussed the ambiguities that surround the distinction between positive and negative reinforcement. Seven distinguished behavior analysts commented on their article. The authors believe that this dialogue represented a constructive step toward clarification of an important concept within…

Michael (1975) reviewed efforts to classify reinforcing events in terms of whether stimuli are added (positive reinforcement) or removed (negative reinforcement). He concluded that distinctions in these terms are confusing and ambiguous. Of necessity, adding a stimulus requires its previous absence and removing a stimulus its previous presence.…