Performance of three severely mentally retarded adults on vocational response chains during extinction

The intrachain performance patterns of three severely retarded adults were analyzed under continuous reinforcement and extinction schedules. The three subjects performed a nine-step operant chain that required the placement of eight electrical components in a circuit board blank. The time to perform the entire chain and the time taken at each step of the chain were electronically monitored. A combined multiple-baseline, ABA reversal design was used. Reinforcers were delivered following completion of the chain during A phases and withheld during the B phase. Data indicated that overall chain performance was slower during extinction, and this effect was due primarily to reduced response speed on the early steps in the chain. Implications of these data for vocational habilitation of retarded adults were discussed.