Effects of imitation training on immediate and delayed imitation by severely retarded children.

Contingent reinforcement was used in training eight severely retarded children who were previously judged to be nonimitative. A yoked control group was given comparable training, but with noncontingent reinforcement. Posttests of imitation of new behavior of a reinforced model showed significant immediate and delayed (15 minutes) imitation only in the contingent-reinforcement group.