Hiroto Okouchi

RESPONSE ACQUISITION BY HUMANS WITH DELAYED REINFORCEMENT

The present experiment examined whether a response class was acquired by humans with delayed reinforcement. Eight white circles were presented on a computer touch screen. If the undergraduates touched two of the eight circles in a specified sequence (i.e., touching first the upper-left circle then the bottom-left circle), then the touches initiated an unsignaled resetting delay culminating in point delivery. Participants experienced one of three different delays (0 s, 10 s, or 30 s). Rates of the target two-response sequence were higher with delayed reinforcement than with no reinforcement. Terminal rates of the target sequence decreased and postreinforcement pauses increased as a function of delay duration. Other undergraduates exposed to yoked schedules of response-independent point deliveries failed to acquire the sequence. The results demonstrate that a response class was acquired with delayed reinforcement, extending the generality of this phenomenon found with nonhuman animals to humans.

An Exploration of Remote History Effects in Humans.

One group of undergraduates responded under a fixedratio (FR) 25 schedule and a second group responded under a differential-reinforcement-of-low-rate (DRL) 5-s schedule (first history phase). Both groups of subjects were then exposed to a differential-reinforcement-of-other-behavior (DRO) 5-s schedule (second history phase), and finally to fixed-interval (FI) 5-s (Experiment 1), variable-interval (VI) 5-s (Experiment 2), extinction, FR, and DRL (Experiment 3) schedules (history testing phase). Response rates under the extinction and the FR schedule in the history-testing phase were higher for subjects with a history of the FR schedule than for subjects with a DRL history. Such a systematic difference by remote histories was not observed when the FI, VI, and DRL schedules were in effect during testing.

Some Determinants of Remote Behavioral History Effects in Humans

Undergraduates were exposed to a series of reinforcement schedules: first, to a fixed-ratio (FR) schedule in the presence of one stimulus and to a differential-reinforcement-of-low-rate (DRL) schedule in the presence of another (multiple FR DRL training), then to a fixed-interval (FI) schedule in the presence of a third stimulus (FI baseline), next to the FI schedule under the stimuli previously correlated with the FR and DRL schedules (multiple FI FI testing), and, finally, to a single session of the multiple FR DRL schedule again (multiple FR DRL testing). Response rates during the multiple FI FI schedule were higher under the former FR stimulus than under the former DRL stimulus. This effect of remote histories was prolonged when either the number of FI-baseline sessions was small or zero, or the time interval between the multiple FR DRL training and the multiple FI FI testing was short. Response rates under these two stimuli converged with continued exposure to the multiple FI FI schedule in most cases, but quickly differentiated when the schedule returned to the multiple FR DRL.

An Experimental Analysis of Another Privacy

The present article discusses how events outside a subject’s skin and not accessible to another subject but to an experimenter may contribute to experimental analyses of private events. Of 16 undergraduates, 8, referred to as instructors, first learned conditional discriminations (i.e., 81 C1, 82C2, 83C3, and 84C4) in a standard matching-to-sample (MTS) task with the stimuli 8s as the samples and the stimuli Cs as the correct comparisons. Then the other 8 subjects, learners, were exposed to modified MTS trials in which responses of the learnElrs were reinforced or punished not by the experimenter but by the instructors. Conditional discriminations to be established were A 1 C1, A2C2, A3C3, and A4C4, in which the sample stimuli As were presented simultaneously with the stimuli 8s so that the instructors could not see the As but only the 8s. For 2 of the 8 pairs, the learners learned the AC conditional discriminations from the instructors who were not accessible to the stimuli As. Functionally, private events have been defined by their accessibility rather than their structure (e.g., Skinner, 1953). In this context, therefore, the stimuli As may be characterized as a kind of private events within the present 2 pairs of instructors and learners.

Differential Reinforcement of Human Self-Reports about Schedule Performances

A report to have responded slowly was reinforced after a fixed-ratio schedule, whereas a report to have responded rapidly was reinforced after a differential-reinforcement-of-Iow-rate schedule. All 5 undergraduates reported they had responded slowly when the last interresponse time during the preceding schedule had been short, and had responded rapidly when the last interresponse time had been long. This referent-report relation was not observed when every report was reinforced nondifferentially. The results demonstrate that the self-reports were affected by the differential reinforcement when schedule performances were their referent.

An Exploration of Remote History Effects in Humans: II. The Effects under Fixed-Interval, Variable-Interval, and Fixed-Ratio Schedules.

Five undergraduates responded under a fixed-ratio (FR) 145 schedule, and 5 others responded under a differential-reinforcement-of-low-rate (DRL) 20-s schedule. Both groups were then exposed to a differential-reinforcement-of- rates-with-pacing 1 s < interresponse time (IRT) ≤ 2 s schedule. Following this, probe sessions under fixed-interval (FI) 20-s, variable-interval (VI) 20-s, and Fr 145 schedules were interspersed among baseline sessions of the 1 s < IRT ≤ 2 s schedule. Response rates under the FI and VI schedules were higher for participants with a history of the FR schedule than for those with a DRL history. Under the FR schedule, such a systematic difference by remote histories was observed only during the first of the 3 probe sessions.

A Revised Procedure for Analyzing Private Events.

One member of each pair of 52 undergraduates, referred to as a learner, was trained BC conditional discriminations, with B stimuli as the samples and C stimuli as the correct comparisons. Responses of the learner were either reinforced or punished by another member of each pair, an instructor, who had previously mastered AC conditional discriminations, with A stimuli as the samples. The B sample stimuli were presented simultaneously with the A stimuli so that only the instructor could see the latter. Each learner mastered the BC conditional discriminations from his or her instructor, regardless of whether the learner saw the instructor in advance or not. Performance was less accurate when the B stimuli corresponded 83.3% with the A stimuli than when they corresponded 100%. These results extend previous findings on private events obtained from only two of eight pairs when the stimuli always corresponded.

Stimulus control and generalization of remote behavioral history.

Two experiments were conducted to assess stimulus control and generalization of remote behavioral history effects with humans. Undergraduates first responded frequently under a fixed-ratio (FR) schedule in the presence of one line length (16 mm or 31 mm) and infrequently on a tandem FR 1 differential-reinforcement-of-low-rate (DRL) schedule when a second line length (31 mm or 16 mm) was present. Next, an FR 1 schedule in effect in the presence of either stimulus produced comparable response rates between the stimuli. Finally, a tandem FR 1 fixed-interval (FI) schedule was in effect under those same stimuli (Experiment 1) or under 12 line lengths ranging from 7 to 40 mm (Experiment 2). In both experiments, responses under the tandem FR 1 FI schedule were frequent in the presence of stimuli previously correlated with the FR schedule and infrequent in the presence of stimuli previously correlated with the tandem FR 1 DRL schedule. Short-lived but systematic generalization gradients were obtained in Experiment 2. These results show that previously established rates of behavior that disappear when the establishing contingencies are changed can subsequently not only reappear when the contingencies change, but are controlled by and generalize across antecedent stimuli.