Hiroto Okouchi

Abstract Three pigeon dyads were exposed to a two‐component multiple schedule comprised of two tandem variable‐interval 30‐s interresponse time (IRT) > 3‐s schedules in the presence of different stimuli. Pecks to keys by both pigeons of a dyad occurring within 500 ms of one another were required for reinforcement under one tandem schedule (the coordination component), and such coordinated responses were not required under the other (the control component). The terminal link of each schedule ensured that the reinforced coordination response was an IRT > 3 s. Rates of coordinated IRTs > 3 s and total rates of coordinated responses (composed of IRTs > 3 s and IRTs ≤ 3 s) were higher in the coordination components than in either of two different control components in which coordination was not required for reinforcement. This difference in coordinated responses in the presence and absence of the coordination requirement under stimulus control transitorily deteriorated and then was reestablished when the relation between the stimulus and the coordination contingency or its absence was reversed. The results show coordinated responding to function as a discriminated social operant.

Abstract Although hypothetical rewards have been used almost exclusively in human discounting studies, investigations of their validity are limited. The present experiment compared the discounting of monetary reward value by probability across conditions in which the rewards were real, potentially real, and hypothetical. Twenty‐four undergraduates choose between an uncertain large reward and a certain small reward 60 times (trials). In the real and hypothetical reward conditions, the participants made choices with real and hypothetical money, respectively, in every trial. In the potentially real condition, they did so with real money in randomly selected three of the 60 trials and with hypothetical money in the remainder. The log₁₀‐transformed h values of a hyperbolic probability‐discount function and the values of the area under the curve with an ordinal transformation of odds against were higher and lower, respectively, in the potentially real and in the hypothetical reward conditions than in the real reward condition, demonstrating that the probability discounting of hypothetical monetary rewards was larger than that of real rewards. These results suggest that future studies are required to identify why the hypothetical reward procedure overestimates the discounting rates of real rewards.

Study objective: Effects of naming training and comparison-as-node training on the establishment of stimulus equivalence were examined. Design: Group comparison and within-subject comparison designs were used. Participants: 13 undergraduates participated. Intervention: In Phase 1, all participants experienced matching-to-sample training under the linear-series training structure, followed by a test examining whether three 5-member equivalent classes had been established. In Phase 2, the participants experienced the same matching-to-sample training and equivalent class test as Phase 1, but with different stimulus sets. Prior to this, participants were given naming training, comparison-as-node training, or no additional training. Measures: Percentage of correct responses and response latency. Results: No participant established stimulus equivalence in Phase 1. In Phase 2, participants who had received naming training or comparison-as-node training established stimulus equivalence, whereas participants without such additional training did not. Conclusion: Prior training on comparison-as-node, as well as on naming, contributed to the establishment of stimulus equivalence.

Study objective: The present study examined effects of a remote history of a DRL schedule on interresponse times (IRTs) under a VI schedule with human subjects. Design: Double-history, single-history, and no history conditions were compared across subjects. Setting: The experiment was conducted individually in a room. Subjects: Two male and eleven female undergraduates with no experience of reinforcement experiments, 19 to 22 years old, participated. Procedure: In the doublehistory condition, DRL 1-s with LH 1-s, DRL 5-s with LH 5-s, and VI 5-s schedules were in effect in that order. The single-history subjects were exposed only to the last two schedules, whereas the no-history subjects experienced only the VI 5-s schedule. Results: For all subjects in the double-history condition, IRTs longer than 1s and equal to or shorter than 2s, which had been reinforced differentially under the DRL 1-s with LH 1-s, emitted more frequently during the last five VI 5-s sessions than during the first five. Such a systematic difference was not observed in the single-history and no-history conditions. Conclusion: These results suggest that a schedule history affected remotely on the VI responding, and that the IRT was a useful measure for examining the remote history effects.