| Abstract: | A multielement design was used to evaluate the effects of three reinforcement conditions on the free-operant and challenging responses of two individuals with severe disabilities. Preference assessments identified three stimuli that could function as reinforcers for each participant. Reinforcers were delivered on a variable ratio schedule for a free-operant response. In the participant-selected condition, each reinforcer delivery consisted of placing an array of three different stimuli in front of the participant, who was allowed to select one. In the constant condition, each reinforcer delivery consisted of placing an array of three identical stimuli in front of the participant. Within each session the three stimuli were held constant, but varied across sessions. In the experimenter-selected condition, each reinforcer delivery consisted of an array of three identical stimuli being placed in front of the participant. Within each session, the three stimuli were presented in an order predetermined by the experimenter such that, on average, each stimulus was available every third reinforcer delivery. For both individuals, the participant-selected condition resulted in lower average rates of challenging responses and slightly higher average free-operant response rates. No differences in responding were noted between the constant condition and the experimenter-selected condition. © 1998 John Wiley & Sons, Ltd. |
