A teaching procedure in which a trainer completes all but the last behavior in a chain, which is performed by the learner, who then receives reinforcement for completing the chain. When the learner shows competence in performing the final step in the chain, the trainer performs all but the last two behaviors in the chain, the learner emits the final two steps to complete the chain, and reinforcement is delivered. This sequence is continued until the learner completes the entire chain independently.