Effects of increased response effort on self-injury and object manipulation as competing responses

We evaluated the effects of a response-effort intervention on the occurrenc e of self-injurious hand mouthing and a competing response (object manipula tion) with 4 individuals who had profound developmental disabilities. Durin g Phase 1, results of functional analyses showed that all participants enga ged in high levels of hand mouthing in the absence of social contingencies, suggesting that the behavior was maintained by automatic reinforcement. In Phase 2, preferred leisure items were identified for participants during a ssessments in which duration of leisure item manipulation was used as the i ndex of preference: In Phase 3, participants were observed to engage in hig h levels of hand mouthing and in varying levels of object manipulation when they had free access to their most preferred leisure items during baseline . The effects of increased response effort on hand mouthing and object mani pulation were then evaluated in mixed multiple baseline and reversal design s. The response-effort condition was identical to baseline, except: that pa rticipants wore soft, flexible sleeves that increased resistance for elbow flexion but still enabled participants to engage in hand mouthing. Results showed consistent decreases in SIE and increases in object manipulation dur ing the response-effort condition for all participants. These results sugge sted that a less preferred reinforcer (produced by object manipulation) may substitute for a more highly preferred reinforcer (produced by hand mouthi ng) when response effort for hand mouthing was increased.