Date of Award


Degree Type


Degree Name

Doctor of Philosophy


Behavior modification research has shown that commonly employed prompting procedures may not be the most effective means of facilitating acquisition of visual discrimination skills in retarded children. Researchers have identified stimulus shaping as a successful procedure for teaching such skills. In this procedure, the topographical stimulus configuration of a task is gradually changed over trials. The initial discrimination is made easy, and then gradually becomes more difficult as training progresses. It is presently unclear whether or not a stimulus shaping procedure might be effective in enhancing learning on visual-motor tasks. The purpose of this thesis was to compare the relative effectiveness of a stimulus shaping procedure with a common prompting procedure for training these skills to retarded children.;Three experiments were conducted to assess the relative effectiveness of these two procedures. Each experiment used different training tasks. In each experiment, six low functioning retarded children were studied. Each subject received concurrent training on two tasks. One task was trained with a stimulus shaping procedure and the second task was trained with a common prompting procedure. The therapist provided successive prompts, as necessary, to insure correct performance of the target response on each training trial. The types of prompts delivered, in sequence, were: (a) verbal instructions (VI) only, (b) VI + pointing, (c) VI + modelling, (d) VI + physical contact, and (e) VI + physical guidance. The number of errors produced and the types of prompts delivered were recorded as dependent measures. The training time to criterion was estimated as a function of the number of verbal instructions delivered. Interobserver reliability of the dependent measures was assessed.;The results indicated that, in general, training with the stimulus shaping procedure (a) required less training time to criterion (in two experiments only), (2) always resulted in fewer errors, (3) always required fewer, and milder types of, therapist's prompts, and (4) always resulted in more reinforcement, relative to training with the common prompting procedure.;These results were discussed in terms of the applied value of employing stimulus shaping training strategies in the clinical domain. Procedural issues and implications for future research were also discussed.



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