摘要:

Young men pulled a plunger on mixed and multiple schedules in which periods of variable‐interval monetary reinforcement alternated irregularly with periods of extinction (Experiment 1), or in which reinforcement was contingent on different degrees of effort in the two alternating components (Experiment 2). In the baseline conditions, the pair of stimuli correlated with the schedule components could be obtained intermittently by pressing either of two observing keys. In the main conditions, pressing one of the keys continued to produce both discriminative stimuli as appropriate. Pressing the other key produced only the stimulus correlated with variable‐interval reinforcement or reduced effort; presses on this key were ineffective during periods of extinction or increased effort. In both experiments, key presses producing both stimuli occurred at higher rates than key presses producing only one, demonstrating enhancement of observing behavior by a stimulus correlated with the less favorable of two contingencies. A control experiment showed that stimulus change alone was not an important factor in the maintenance of the behavior. These findings suggest that negative as well as positive stimuli may play a role in the conditioned reinforcement of human behav

ISSN:0022-5002    

DOI:10.1901/jeab.1980.34-239

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Pigeons received variable‐interval reinforcement for key pecking during presentations of horizontal and vertical line‐orientation stimuli, while pecks during five intermediate orientations were extinguished. Lowest peck rates were observed during presentations of negative stimuli adjacent to the positive orientations while peck rate during 45 degrees (the intermediate negative orientation) was relatively high, i.e., there were negative contrast shoulders. When peck rates were manipulated in the positive orientations, peck rate in neighboring orientations changed in the opposite direction. Contrast shoulders faded after prolonged training. A second type of contrast, local contrast, was correlated with similarity of preceding stimulus and different average peck rates during different stages of the discrimination process. The data suggest that sequential local contrast accompanying the formation of a discrimination contributes to the form of generalization gradients. Blough's model of stimulus control predicts the changes in gradient form described here, but may not accurately depict the underlying processes responsible for gradient f

ISSN:0022-5002    

DOI:10.1901/jeab.1980.34-263

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Six pigeons were trained to detect differences between two white stimuli, S1and S2differing in duration and arranged probabilistically on the center key of a three‐key chamber. Detection performance was measured at two levels of discriminability. At one level, S1was five seconds and S2was thirty seconds. At the other level, S1was twenty seconds and S2was thirty seconds. The procedure was a standard signal‐detection yes‐no design in which stimulus‐presentation probability was varied from .1 to .9 at both discriminability levels. On completion of the center‐key stimulus, a peck on the center key darkened the center‐key light and turned on the two red side keys. A left‐key response was “correct” on S1trials, and a right‐key response was “correct” on S2trials. Correct responses produced food reinforcement on a variable‐ratio 1.3 schedule. Incorrect responses produced three second blackout. Discriminability was higher for the five‐second versus thirty‐second conditions than for the twenty‐second versus thirty‐second conditions, but there were no differences in sensitivity of behavior to reinforcement variation for the two stimulus pairs. Response bias was a function of the relative reinforcement

ISSN:0022-5002    

DOI:10.1901/jeab.1980.34-273

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Pigeons' key pecks were reinforced with food on a fixed‐interval schedule. Food also was available at variable time periods either independently of responding or for not key pecking (a differential‐reinforcement‐of‐other‐behavior schedule). The latter condition arranged reinforcement following the first pause oftseconds after it became available according to a variable‐time schedule. This schedule allowed separation of the effects of pause requirements ≤ five‐seconds and reinforcement frequency. The time spent pausing increased as the duration of the pause required for reinforcement increased from 0 to 30 seconds and as the frequency of reinforcement for pausing increased from 0 to 2 reinforcers per minute. Key pecking was more evenly distributed within each fixed interval with shorter required pauses and with more frequent reinforcement for pausing. The results complement those obtained with other concurrent schedules in which the same operant response was reinforced in

ISSN:0022-5002    

DOI:10.1901/jeab.1980.34-285

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

The problem of maintaining independence between response rates and reinforcement probabilities when determining the effect of varying the response‐reinforcement contingency upon free‐operant behavior was solved by programming local reinforcement probabilities for response and no response on a second‐by‐second basis. Fifty‐seven rats were trained to lever‐press on schedules of water reinforcement involving different values of contingency. All rats were first trained on a high positive contingency and then shifted to less positive, zero, or negative contingencies. Under these conditions, rate of lever‐pressing declined appropriately when the contingency between response and reinforcement decreased or was made negative. The decline in rate produced by a zero contingency cannot be attributed to extinction, since the probability of reinforcement given the occurrence of a response was the same as for the positive contingency from which the shift to zero was made. That is, there was no change in the opportunity for response‐reinforcement contiguity. It was concluded that the technique of programming local reinforcement probabilities offers promise for more critical examinations of the effects of contingency upon free

ISSN:0022-5002    

DOI:10.1901/jeab.1980.34-297

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

In Experiment 1, pigeons were exposed either to paired or to unpaired presentations of a tone and grain, and then to paired presentations of a keylight with the tone. Substantial second‐order conditioned pecking to the keylight was produced in the birds that had received paired presentations of tone and grain. In Experiment 2, second‐order pecking to the keylight increased in probability across four groups that had received, respectively, 20, 80, 140, or 200 paired presentations of tone and grain. In Experiment 3, the amount of pecking directed towards a keylight which predicted the first‐order, tone CS was as substantial in birds without a prior history of key pecking as in birds with such a history. A further experiment failed to discover any significant differences in the levels of second‐order pecking to a keylight paired with a first‐order tone CS or with a first‐order keylight CS. Thus, an auditory signal that does not itself support pecking may enable a localized visual stimulus to evoke

ISSN:0022-5002    

DOI:10.1901/jeab.1980.34-305

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Pigeons were trained to peck a key under a multiple fixed‐ratio 25 fixed‐ratio 175 schedule of food presentation. In the first condition, either a mirror or the opportunity to produce a 30‐second timeout were available. In a second condition, mirror and timeout availability were reversed for the two groups. Following a return to the initial condition, mirror and timeout keys were presented together for all birds. Mirror and timeout responses occurred predominantly in the pause in the larger fixed‐ratio component, regardless of whether the opportunities for the two responses were available singly or together. Mirror responding occurred in a greater proportion of the pauses than did timeouts. When the opportunities for both mirror pecking and timeout were available concurrently, they occurred with probabilities similar to those under the single conditions. Within the pause itself, mirror responses most frequently occurred immediately after reinforcement. Timeouts occurred most frequently toward the end of the pause, and some timeouts occurred in the early part of the run. Longer preratio pausing occurred in the larger fixed‐ratio component in the conditions in which the mirror was present, whether or not any mirror pecks were

ISSN:0022-5002    

DOI:10.1901/jeab.1980.34-319

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY

摘要:

Three pigeons were studied on concurrent, unsignaled, avoidance schedules in a two‐key procedure. Shock‐shock intervals were two seconds in both schedules. The response‐shock interval on one key was always 22 seconds, while the response‐shock interval associated with the other key was varied from 7 to 52 seconds in different experimental conditions. Response rates on the key associated with the varied schedule tended to decrease when the response‐shock interval length was increased. Responding on the key associated with the constant schedule was not systematically

ISSN:0022-5002    

DOI:10.1901/jeab.1980.34-329

出版商:Blackwell Publishing Ltd    

年代:1980

数据来源: WILEY