摘要:

In two experiments, the performance of rats under constant‐probability and arithmetic variable‐interval schedules respectively was compared when the concentration of a liquid reinforcer was varied within sessions; in other sessions, half of the reinforcers were randomly omitted. When the discriminative function of the reinforcer as a signal for a decrease in the probability of reinforcement was attenuated (the constant‐probability schedule) the postreinforcement pause duration was nevertheless an increasing function of reinforcer magnitude. This relationship was also present, but more marked, when the temporal discriminative function of the reinforcer was enhanced (the arithmetic schedule). These results suggested that reinforcement has an unconditioned suppressive effect on the reinforced response distinct from any discriminative function it may acquire. The reinforcement‐omission effect, where response rate accelerates following omission, was observed when the reinforcer functioned as an effective temporal discriminative stimulus, but not when such temporal control was

ISSN:0022-5002    

DOI:10.1901/jeab.1978.30-1

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Pigeons chose between an immediate 2‐second reinforcer (access to grain) and a 6‐second reinforcer delayed 6 seconds. The four pigeons in the control group were exposed to this condition initially. The four experimental subjects first received a condition where both reinforcers were delayed 6 seconds. The small reinforcer delay was then gradually reduced to zero over more than 11,000 trials. Control subjects almost never chose the large delayed reinforcer. Experimental subjects chose the large delayed reinforcer significantly more often. Two experimental subjects showed preference for the large reinforcer even when the consequences for pecking the two keys were switched. The results indicate that fading procedures can lead to increased “self‐control” in pigeons in a choice between a large delayed reinforcer and a small immediate r

ISSN:0022-5002    

DOI:10.1901/jeab.1978.30-11

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Two groups of pigeons were exposed to a simple reaction‐time procedure in which mean foreperiod duration was 5, 10, or 20 seconds. For one group, the foreperiods had an arithmetic, or rectangular, distribution; for the second group, they had a constant‐probability, or Bernoulli, distribution. Under both distributions, mean response latency was an increasing, negatively accelerated function of mean foreperiod duration. On a given trial, response latency was a function of its associated foreperiod duration: latency was a decreasing function of foreperiod duration in the arithmetic distribution, and an increasing function of foreperiod duration in the constant‐probability distribution. Examination of the distribution of latencies revealed a harmonic structure reminiscent of distributions of interresponse times under variable‐interval schedules of reinforcement. Taken together, the results confirm and extend previous findings with human subjects, and also suggest numerous similarities to behavior maintained by variable‐interval

ISSN:0022-5002    

DOI:10.1901/jeab.1978.30-19

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

The behavior of rats under concurrent variable‐interval schedules of negative reinforcement was examined. A single one‐minute variable‐interval programmer determined the availability of 30‐second timeouts from electric shock. These were assigned to one or the other of the two component schedules with a probability of 0 to 1.0. The response requirement for the component schedules was standing to the right or left of the center of the experimental chamber. With a six‐second changeover delay, the relative time spent under one component schedule varied directly and linearly with the relative number of timeouts earned under that component schedule. The absolute number of changeovers was highest when a similar number of timeouts was earned under each component schedule, and lowest when all or nearly all timeouts were earned under one component schedule. In general, these relations are similar to those reported with concurrent variable‐interval schedules of positive re

ISSN:0022-5002    

DOI:10.1901/jeab.1978.30-31

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Behavior maintained by stimulus‐reinforcer pairings was examined. Guinea pigs maintained at 85 per cent of free‐feeding weights reliably contacted a retractable lever presented before delivery of a single piece of guinea‐pig chow or a 45‐milligram guinea‐pig pellet. When animals were given free access to one food and received the second food preceded by the lever, contact responses persisted. Such responses seldom occurred when a single food was freely available and was also delivered after lever presentation. Introduction of an omission training (negative automaintenance) procedure, in which lever contacts resulted in lever retraction and prevented food delivery, strongly reduced lever contacts. Observation indicated that mouthing the food cup, instead of the lever, became the prominent behavior during the prefood stimulus under the omission training

ISSN:0022-5002    

DOI:10.1901/jeab.1978.30-37

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Three rats were trained on a fixed‐ratio escape procedure in which responding produced one of two equiprobable outcomes—a 10‐second or 60‐second shock‐free period. Before the fixed‐ratio requirement was satisfied, brief shocks were presented at irregular intervals averaging either 15 or 30 seconds. Two conditions, differing in the relationship between exteroceptive stimuli and the outcomes, were studied. In the uninformative (uncorrelated) condition, the same stimulus was presented during both outcomes. In the informative (correlated) condition, one stimulus was present during the 10‐second outcome only; another stimulus was present during the 60‐second outcome only. Subjects pressed faster in the uninformative condition than they did in the informative condition. The inadequacy of the information hypothesis in accounting for the findings is discussed, and an alternative hypoth

ISSN:0022-5002    

DOI:10.1901/jeab.1978.30-47

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Three pigeons were exposed to two‐key discrete‐trial concurrent schedules of reinforcement. Red and white key colors alternated irregularly and the assignment of reinforcers depended on key color. The red‐key schedules were held constant, with the scheduled relative frequency of reinforcement for left‐key pecks set at 0.75, while the white‐key schedules varied. When the location of white‐key reinforcement was changed from one side to the other, while its overall frequency was constant, red‐key choices shifted in the same direction as white‐key choices, an induction effect. When the overall frequency of white‐key reinforcement was changed while its location remained constant, red key choices shifted in a direction opposite to white‐key choices, a contrast effect. Both induction and contrast effects were clearer when the overall frequency of red‐key reinforcement was reduced. These data demonstrate that the allocation of responding may exhibit schedule interaction effects similar to those commonly repor

ISSN:0022-5002    

DOI:10.1901/jeab.1978.30-53

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Variability of response location was studied in monkeys performing in a six‐lever chamber. Fixed‐ratio schedules, ranging from FR 1 to FR 300, generated a high degree of stereotypy of response location. In contrast, fixed‐interval schedules of comparable reinforcement frequencies (0.06 to 4 minutes) generated much greater variability. These results failed to confirm any simple relationship between response variability and intermittence of reinforcement. Rather, variability seems to be determined by the particular characteristics of the reinforcement sch

ISSN:0022-5002    

DOI:10.1901/jeab.1978.30-63

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Three pigeons, previously trained to discriminate different numbers of responses (fixed ratios), were tested under different reinforcement contingencies (payoff matrices) at two levels of sensitivity. For one subject, relative reinforcement magnitude was varied—at first, across sessions and then, at midsession by reversing values—without exteroceptive cues. For another, relative reinforcement magnitude and/or probability was varied every 50 trials with cues by correlating different payoff matrices with different key colors. For the third subject, relative reinforcement probability was varied more frequently with cues—in the limit, at random—to demonstrate stimulus control of response bias on a trial‐by‐trial basis. A signal‐detection analysis showed that bias changed with payoffs, for as many as seven different matrices, while sensitivity remained unchanged. The obtained functions (receiver operating characteristics) were similar under different payoff conditions, which suggests that a single mechanism controls bias. However, they differed enough in slope to require a relatively complex account (e.g., the general Gaussian model of dete

ISSN:0022-5002    

DOI:10.1901/jeab.1978.30-69

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY

摘要:

Six rats received food contingent on pressing a lever on fixed‐ratio 1, fixed‐interval 30‐second, and fixed‐interval 60‐second schedules, with concurrent access to a drinking spout, a running wheel, and a block of wood. Drinking, running, and chewing were monitored automatically, and these and other activities were observed directly during selected sessions. Because all sessions ended after delivery of 60 pellets, total time available for activities other than eating increased over the three schedules. Time spent contacting the lever and visiting the food tray increased in proportion to total available time, whereas the time spent in other activities changed in a complex manner such that drinking was the dominant adjunctive behavior in the 30‐second condition, and running or chewing the dominant adjunctive behavior in five of six rats in the 60‐second condition. General activity and grooming also occupied significant amounts of time. In a subsequent part of the experiment, running and chewing were prevented, and the majority of other activities, especially drinking and grooming, increased. The results show that (a) FI schedules of food reinforcement are accompanied by a wide variety of adjunctive activities; (b) the preferred activity differs according to the schedule duration; and (c) the extent to which activities substitute for one another is limited by the tendency for different activities to occupy different parts of the interreinforce

ISSN:0022-5002    

DOI:10.1901/jeab.1978.30-83

出版商:Blackwell Publishing Ltd    

年代:1978

数据来源: WILEY