Assessing stimulus preferences and testing stimuli as reinforcers for children and adults with profound mental retardation and multiple disabilities

It is essential in the development of a successful training program for persons with profound mental retardation and multiple disabilities (PMD) to use effective reinforcers. During several experiments, a single-stimulus (SS) preference assessment has been used to identify preferred stimuli that might be reinforcers with individuals with PMD. With this method, the activities or stimuli that are being assessed are presented individually to a client. The client has a limited period of time in which to respond, and an appropriate response is followed by the opportunity to interact with the stimulus for a short time. Each stimulus is typically presented a certain number of times (e.g., 10 trials), and a high preference (HP) item is defined as a stimulus that the client responded to on 80% or more of the trials. However, there have been some discrepancies in the literature about how the SS procedure has been conducted. Some researchers have defined the preference response as a physical approach toward a presented stimulus, while others have accepted either an approach response or happiness indicators. As well, some researchers allow a participant 5 s after the stimulus has been presented to indicate a preference, while others have allowed 30 s. Each of these variations in the SS procedure may lead to different results in identifying preferred stimuli and reinforcers for these individuals. My research investigated these methodological variations to determine which was the most effective method to identify highly preferred non-edible stimuli and reinforcers for individuals with PMD. Also, I compared the SS preference assessment method for identifying preferred stimuli and reinforcers to the opinions of experienced teachers or caregivers who were familiar with each of the participants.; In Experiment 1, I studied eight participants with PMD, and investigated which preference assessment response (approach behaviors versus approach and/or happiness behaviors) was the most sensitive in identifying preferred stimuli and reinforcers. The design was an ABAB design. The A phases were an SS preference assessment in which the preference response was defined as an approach behavior, in order to determine which of six stimuli was the most highly preferred. The HP stimulus was then tested for its reinforcing value in maintaining the pressing of a micro-switch. The B phases were the same as the A phases, except that the preference response was defined as approach and/or happiness behaviors. For some of the participants, the phases were reversed (BABA). The two response definitions were approximately equal in identifying HP stimuli and reinforcers.; In Experiment 2 I studied 8 participants with PMD (3 of whom were new, and 5 of whom had previously participated in Experiment 1) and investigated which response interval (5 s versus 30 s) was the most effective in identifying preferred stimuli and reinforcers. The approach only preference response from Experiment 1 was used. Like Experiment 1, the design was an ABAB design, in which half of the participants received the conditions in the reverse order (BABA). During the A phases, the SS preference assessment allowed each participant 5 s to emit the preference response. The B phases were the same as the A phases, except that the participant was allowed 30 s to emit the preference response. The HP stimuli were then tested for their reinforcing value. The 30 s response interval was superior to the 5 s interval in identifying reinforcers. In both experiments, there was no correlation between caregivers' rankings of the stimuli and whether they were reinforcers for the participants. Identifying the most effective preference assessment method is important, because it allows us to identify reinforcers for teaching programs, and to increase the quality of life for individuals with PMD.