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There has been growing interest in teaching sign language to autistic children who have failed to develop speech. However, controlled experimentation in this area is nonexistent. In the present study, four nonverbal autistic children were taught expressive sign labels for common objects, using a training procedure that consisted of prompting, fading, and stimulus rotation. The efficacy of the procedure was demonstrated in a multiple-baseline design across objects. The results were reliable, replicable across children, and generalizable across therapists. A stimulus control analysis demonstrated that, for three of the children, correct signing was controlled solely by the visual cues associated with the presentation of a given object and was independent of respect to the known perceptual and linguistic deficits of autistic children.

This study sought to identify some of the variables controlling the severely aggressive behavior of two retarded children. In Experiment 1, each child was presented with several demand and nondemand situations. Aggression was frequent in the demand situations and rare in the nondemand situations. When a stimulus correlated with the termination of demands was introduced, aggression fell to a near zero level. In Experiment 2, for one child, a variety of preferred reinforcers was introduced into the demand situation contingent on correct responding. Aggression abruptly decreased to a low level. Experiments 3 and 4 involved the second child. In Experiment 3, this child was permitted, in one condition, to leave the demand situation if he emitted a nonaggressive response. Aggression decreased to a low level. In Experiment 4, he was prevented, in one condition, from leaving the demand situation in spite of high levels of aggression. Aggression fell to a near zero level. In Experiments 3 and 4, he was permitted, in several conditions, to leave the demand situation following aggressive behavior. Aggression increased to a high level. The results suggested that: (1) aggression can sometimes function as an escape response; and (2) escape-motivated aggression can be controlled by: (a) introducing strongly preferred reinforcers to attenuate the aversiveness of the demand situation; (b) strengthening an alternative, nonaggressive escape response; or (c) using an escape-extinction procedure.