摘要:

Monkeys were trained with food reinforcement in a chamber containing four groups of three levers. For each session the monkey's task was to learn a new four‐response chain by pressing the correct lever in each group. A stable pattern of learning resulted, and the number of errors reached a steady state from session to session. The technique was then used to determine how various durations of timeouts, following errors, affected the acquisition of new chains. With no timeout, the monkeys made a great many errors, due in large part to superstitious responses within the reinforced chain. Timeout durations ranging from 1 sec to 4 min reduced the number of errors substantially. A second experiment investigated the effects upon acquisition errors of presenting a single light (an “instruction” stimulus) over the correct lever. When this light did not influence the monkeys' responses to the three alternatives, the chains were learned as without it. When the light did control responding, the monkey pressed the appropriate sequence of levers but did not learn the sequence. Thus, when the light was removed, the monkey performed as if learning that sequence for the first

ISSN:0022-5002    

DOI:10.1901/jeab.1968.11-651

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

The relative importance of interreinforcement time and interreinforcement responses was evaluated by varying each independently. To do this, a blackout was presented after each non‐reinforced response under both fixed‐ratio and fixed‐interval schedules of reinforcement. Manipulating the blackout duration under the fixed‐ratio schedule caused interreinforcement time to vary without affecting the number of interreinforcement responses. Pigeons' post‐reinforcement and post‐blackout response latencies were found to increase linearly with interreinforcement time. Under the fixed‐interval schedule, the same blackout manipulations changed the number of interreinforcement responses without affecting interreinforcement time. Post‐reinforcement and post‐blackout response latencies under this condition were approximately constant. These results suggest that responding is controlled by interreinforcement time and is not influenced by the number of responses emitted betwe

ISSN:0022-5002    

DOI:10.1901/jeab.1968.11-661

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

Pigeons were exposed to reinforcement both for short (2

ISSN:0022-5002    

DOI:10.1901/jeab.1968.11-669

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

Reinforcements were arranged independently of the pigeon's behavior by concurrent variable‐interval schedules. The reinforcements arranged by one of the schedules occurred when the chamber was illuminated with amber light, and the reinforcements arranged by the other schedule occurred when the chamber was illuminated with blue light. Both schedules functioned concurrently, but reinforcers were delivered by each only in the presence of the appropriate stimulus condition. A response on a white key, the only key in the chamber, alternated the stimulus condition and the effective schedule. The results of this procedure were similar to those obtained with concurrent response‐dependent variable‐interval schedules of reinforcement. The proportion of the total session time spent in the presence of a schedule component approximated the proportion of the total number of reinforcements in the component. Changeover rate was a decreasing function of the changeover delay and of the difference between the relative rates of reinforcement for each pair of concurrent sche

ISSN:0022-5002    

DOI:10.1901/jeab.1968.11-683

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

A multiple schedule of food reinforcement for key‐pecking was arranged which consisted of nine fixed‐ratios, each of which operated in the presence of a different stimulus. Pigeons could complete a given fixed‐ratio within the multiple schedule or, by pecking a second key, could switch from the fixed‐ratio schedule to a variable‐ratio schedule consisting of the same nine ratios. Stable switching behavior was established which did not maximize simple probability or rate of reinforcement. Instead, the subjects showed a stable preference for the variable‐ratio schedule of food reinforcement. Increasing the number of responses required to switch, and removing the occasions on which reinforcement was delivered after a single response in the variable schedule, decreased the number of switches to the variable schedule. Periods of delay interposed between a completed switch and the availability of reinforcement after one response in the variable schedule also decreased switching to the variable schedule, particularly at long dela

ISSN:0022-5002    

DOI:10.1901/jeab.1968.11-689

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

Pigeons were studied in two experiments designed to explore the effects of deprivation level upon responding in each link of a two‐link chained schedule. The stimulus associated with the terminal link of the chain can be both a discriminative stimulus (SD) for responding in the presence of the stimulus and a conditioned reinforcer (Sr) for responding in the preceding link. Previous findings have indicated that the Srfunction was more readily weakened by satiation than was the SDfunction,i.e., the rate of responding decreased more rapidly in the initial link of the chain than in the terminal link. The first of the present experiments, in which tests were conducted after a series of sessions, produced different results: rates of responding in the two links declined simultaneously. The second experiment supported the hypothesis that the effects of satiation interact with the duration of maintenance on the satiation procedure: in early sessions the Srfunction was more readily disrupted, but in later sessions the rates of responding in the two links declined simultaneously. Subsequent to this extensive series of identical sessions, the pigeons' deprivation level was altered before a session by pre‐feeding the pigeons up to their normal post‐session weights. The rates of responding failed to reflect fully this change in deprivation in the first such session, suggesting that the pigeons' behavior had become partially independent of deprivation

ISSN:0022-5002    

DOI:10.1901/jeab.1968.11-703

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

Pigeons sometimes peck a key at different rates in the presence of different stimuli, even when the same schedule of reinforcement is correlated with each of these stimuli. The possibility that the occurrence of such stimulus bias is dependent on adventitious effects of food reinforcement in the presence of the stimuli was evaluated by correlating extinction with two stimuli. Both pigeons showed stimulus bias, indicating that the occurrence of this phenomenon is not critically dependent upon any effects of scheduled food reinforcements.

ISSN:0022-5002    

DOI:10.1901/jeab.1968.11-711

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

Pigeons were trained to respond with equal variable‐interval reinforcement in the presence of a white key and also a white key with a vertical line. They were then trained not to respond to the vertical line by extinguishing the response or by reinforcing its non‐occurrence at various frequencies. During training, the rate of key‐pecking in the presence of the white key, maintained by a constant variable‐interval schedule of reinforcement, depended on the frequency of reinforcement in the presence of the line. When lines of different orientations were presented in a generalization test, birds trained with extinction responded more to other orientations than to the vertical line, whereas those trained with high frequencies of reinforcement for not responding tended to respond equally at all line orientations. Intermediate frequencies of reinforcement gave mixed

ISSN:0022-5002    

DOI:10.1901/jeab.1968.11-715

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

A discrimination between two successively alternating stimuli was trained under conditions that maintained equal frequencies of reinforcement in the presence of each of the discriminative stimuli (S1 and S2) but that also reduced the rate of responding to S2. These conditions included a multiple variable‐interval differential‐reinforcement‐of‐low‐rate schedule and a multiple variable‐interval variable‐interval schedule in which responses to S2 were punished. Whenever the rate of responding to S2 was reduced, rate of responding to S1 (behavioral contrast) increased, and the peak of a subsequently obtained generalization gradient did not occur at the expected location (between S1 and S2) but was displaced away from S2, below S1. Discrimination training in which the frequencies of reinforcement earned in S1 and S2 werenotequal (variable‐interval 1‐min variable‐interval 5‐min training) produced contrast and the peak shift only if the rate of responding to S2 had been reduced, as after non‐differential reinforcement in which variable‐interval 1‐min schedules were correlated with SI and with S2. It was concluded that a sufficient condition for the occurrence of behavioral contrast and the peak shift was reduction of the rate of responding to one of two alternating discriminative stimuli and that a peak shift will occur only if contrast had occurred dur

ISSN:0022-5002    

DOI:10.1901/jeab.1968.11-727

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

Five groups of pigeons received seven sessions of variable‐interval reinforcement for pecking a blank white key, followed by either 1, 2, 4, 8, or 16 sessions of training on a successive discrimination in which the positive stimulus was the blank white key and the negative stimulus was a black vertical line on the white key. After training, a generalization test was administered along the line‐tilt continuum. Relative gradients of inhibition became steeper with increased amounts of training, and reliably nonhorizontal absolute gradients were obtained only from groups of subjects with at least four days of training. Therefore, inhibitory stimulus control improves with added training. Several problems with the concept of “inhibition” are examined and some implications of the results for theoretical analyses of operant discrimination learning are di

ISSN:0022-5002    

DOI:10.1901/jeab.1968.11-743

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY