No description available.

No description available.

No description available.

When discriminated IRT procedures have been used to determine preference relations among temporally extended operants, deviations from predictions of the matching law have been found (Hawkes and Shimp, 1974). Using a yoked-control procedure, the present study shows that keypecking in the discriminated IRT procedure has two sources of strength, that arising from the stimulus-reinforcer contingency and that arising from the response-reinforcer contingency Three out of four yoked birds autoshaped to the keylight, and all lead birds showed evidence of control by the keylight under some conditions. As any control of keypecking by the keylight, either discriminated or autoshaped, contributes to deviations from matching, the discriminated IRT procedure does not permit one to draw strong conclusions about preference relations among IRTs.

No description available.

This study addressed the question of whether or not a stimulus paired with the termination of shock would acquire a positive conditioned reinforcing function. Previous investigators have suggested that a stimulus paired with shock termination must increase the frequency of a response upon which it is made contingent. This test for conditioned reinforcement is incomplete because multiple stimulus functions will be established during conditioning trials that can influence the rate of responding. The solution to this multiple stimulus control problem involved the effects of reinforcement upon events antecedent to the criterion response. Reinforcement results in the establishment of discriminative stimulus control. The test for conditioned reinforcement from shock termination, therefore, would involve using the presumed conditioned reinforcer to establish discriminative control for a response. Subjects were four male albino rats of the Wistar strain. The experimental procedure was divided into three phases. The initial phase involved consecutive trials in which a tone was paired with shock offset. The next phase continued tone/shock offset pairings and, in addition, the tone alone was presented sometimes for establishment of a lever press. In the third phase an attempt was made to bring the lever press under the discriminative stimulus control of a light. A successful response shaping effect was obtained for two of the four rats. There was no establishment of discriminative stimulus control for level pressing for the two rats who proceeded to the discrimination test for conditioned reinforcement. Conditioned reinforcement from shock termination was not revealed in this study. The establishment of stable discriminative control over the criterion response would require a strong reinforcer relative to the other established stimulus functions. Future research should concentrate on developing procedures to maximize the conditioned reinforcing properties while minimizing the control from competing stimulus functions.

In this study, six educationally disadvantaged children were taught beginning letter sounds under two teaching conditions. After a baseline of no intervention, a single subject alternating treatments design was used to compare contingent elaborations and token reinforcement within children. Performance between treatments was analyzed in terms of cumulative number of letter sounds learned, total number of letter sounds learned, and maintenance of learning. Token probes were implemented to ascertain whether tokens remained functionally reinforcing over the course of the study. Five children responded to treatment over baseline. Three of these, characterized by above average Wepman auditory discrimination scores, performed better under elaborations until the final third of the study when differential performance between treatments was less pronounced. Remaining subjects, characterized by below average auditory discrimination, showed similar learning under both treatments or, as in the case of one child, no learning. No differences in maintenance were observed. Implications for the classroom and suggestions for further research were discussed.

No description available.

Previous research has shown that variability is a reinforceable dimension of operant behavior. Additionally, it has been demonstrated that learning is facilitated when variability in responding is high. In this research, variability was observed within an operant composed of any sequence of six left and right key presses. Variability was either a requirement for point delivery (VAR conditions) or points were delivered independent of variability (ANY conditions). Two groups of college undergraduates experienced different orders of conditions. One group began the experiment under VAR conditions, and the variability requirement was later removed. The other group began the experiment under ANY conditions, and the variability requirement was later added. A concurrently reinforced target sequence (i.e., an always-reinforced sequence of left and right key presses) was introduced to both groups after these orders of conditions had been experienced. A variety of outcomes resulted. Subjects learned the target sequence when variability was both high and low with non-target points concurrently available. Other subjects learned the target sequence after all non-target point deliveries had been suspended. One subject failed to acquire the target sequence at all. These results were compared to previous findings and possible explanations for the discrepancies were suggested.

Wong Ngai Ying. / Chinese title in romanization: Zi wo jian cha you qiang hua zuo yong dui jie nan biao xian di ying xiang. / Thesis (M.A.Ed.)--Chinese University of Hong Kong, 1987. / Bibliography: leaves 89-99.