Improving and Facilitating the Use of Demanding : From the Stimulus Equivalence Point of View

The present study examined how to facilitate the frequency of appropriate verbal demands by a child with autism. Although this child had made spontaneous demands, his expression was apt to be out of context. That is, he emitted 2 different demand words (R1, R2) under both of 2 different antecedent events (A1, A2), although A1 was the antecedent in the presence of which R1 should be emitted, and A2, R2. Thus, prior to the experiment, A1 and A2, as discriminative stimuli, were considered to have the same function for his demand words R1 and R2. Experiment I attempted to give each antecedent a specific function, so that R1 would be emitted in the presence of A1 (and not A2), and R2, A2 (and not A1). In the training, two picture cards (P1, P2) used as stimuli were matched to A1 and A2 respectively. That is, P1 and P2 were experimentally equivalent as discriminative stimuli for labeling to A1 and A2 respectively. A previous study had reported that when a stimulus took on a new function, the same kind of stimulus as the one just trained also acquired the new function. On that basis, it was hypothesized that A1 and A2 would take on the same discriminative function as P1 and P2 for the responses R1 and R2. In the training, the trainer presented one of the picture cards, and then modeled the appropriate word orally. For example, in the case of P1, the trainer modeled R1. Verbal approval was given contingent on the child's correct imitation. The trainer's model was gradually faded. The results showed that P1 and P2 acquired discriminative stimulus function for R1 and R2 respectively. Appropriate use of R1 and R2 in daily settings improved without further training. It was proposed that symmetric relations, under the conditions of discriminative stimuli for R1 and R2, might emerge between the picture cards and the antecedents on daily settings. Experiment 2 was conducted to examine whether symmetry between two stimuli would emerge if they controlled the same word. A new card, P3, was matched with R2, using the same procedure as in Experiment 1. Symmetry between P2 and P3 (P2/P3, P3/P2) was tested using a two-choice arbitrary matching-to-sample task. P1 from Experiment 1 was used as a distractor stimulus. Although P2/P3 performance occurred, P3/P2 performance did not. That is, the child often chose P1 for P3. After this incorrect choice, the child emitted R1 for P3. These results did not permit a clear conclusion on the hypothesis, so further research is needed. In Experiment 2, after the additional training on R2 for P3, the child became able to use R2 in daily settings in which P3 was the antecedent stimulus and where the child had never before emitted R2. This result suggested that the stimulus equivalence paradigm was applicable for facilitating the generalization of demanding.