Stimulus preference assessments for individuals with developmental disabilities typically involve offering choices among stimuli and providing immediate access to the chosen stimuli. Several researchers have explored the utility of presenting choices verbally, thereby obviating the need to present the choices in tangible form and deliver access to…

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.…

Reinforcers lose their effectiveness when they are presented repeatedly. Early researchers labeled this loss of effectiveness as "satiation" without conducting an experimental analysis. When such an analysis is conducted, "habituation" provides a more precise and empirically accurate label for the changes in reinforcer effectiveness. This paper…