Stimulus control of generalized imitation in subnormal children

Generalized imitation was established in three young subnormal children by reinforcing their imitations of a limited set of modeled actions in the presence of a large ball. A discrimination was then established by training nonimitation in the presence of a small ball. Imitation was then tested for various other ball sizes. Rate of imitation decreased as the test stimuli increasingly differed in size from the large ball. Imitations that were never reinforced occurred at about the same rate as those that were reinforced when in the presence of the large ball in training.