摘要:

Two avoidance‐conditioning experiments in which responding delayed shocks are reported. Rats receiving an average of two shocks per minute (imposed condition) could produce, by pressing a bar, a 3‐min alternate condition. Six (Experiment I) or more (Experiment II) shocks occurred in the alternate condition. All shocks in the alternate condition were delayed and delivered at 1‐sec intervals. With long delays, all subjects produced the alternate condition and spent a large percentage of each session in the alternate condition. The first experiment demonstrated that the longer the delay from onset of the alternate condition to onset of the shocks, the more session time spent in the alternate condition. The second experiment indicated that despite increased shock frequency, behavior is acquired and maintained when responding leads to sufficient delay. Individual subjects produced the alternate condition by bar pressing in essentially one of two patterns. One pattern, termed postshock, involved bar pressing immediately after shock; the other, termed posttransition, involved responding immediately after the transition from the alternate to the imposed condition. These results indicate that shock‐frequency reduction is not necessary for avoidance conditioning; delay to shock onset is suf

ISSN:0022-5002    

DOI:10.1901/jeab.1976.25-3

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

In Experiment I, pigeons' responses produced food according to a fixed‐interval schedule while responses on the key also produced brief stimuli according to a variable‐interval schedule. Each brief stimulus reset the fixed interval. Thus, a brief stimulus occurred irregularly but a fixed minimum time separated the occurrence of food from a brief stimulus. Pauses followed brief stimuli and were followed by an accelerated response rate until another brief stimulus or food occurred. In Experiment II, four control procedures were examined. (1) Brief‐stimulus presentations were omitted, producing a loss of response patterning. (2) A second‐order schedule was studied with fixed‐interval components. This schedule produced patterning following brief stimuli similar in kind and degree to that found in Experiment I. (3) A conjoint schedule was arranged in which food was no longer separated from the stimulus by a fixed time; pauses following the stimulus no longer resulted. (4) A brief food reinforcer replaced the brief visual stimulus, resulting in a constant response rate with no pausing following the brief food stimulus. The results suggest that the brief‐stimulus effects were due to discriminative functions produced by the fixed temporal relation separating the stimulu

ISSN:0022-5002    

DOI:10.1901/jeab.1976.25-15

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Behavioral contrast reliably occurred in pigeons following errorless discrimination training, contrary to Terrace's (1963) observations. In the main experiment, a 60‐sec green keylight, associated with a variable‐interval 30‐sec schedule of reinforcement alternated with a 60‐sec period of extinction when the key was dark. Such aspects of the discrimination training procedure as: (1) the amount of prior nondifferential exposure to the positive stimulus before the discrimination was instituted, and (2) the rapidity with which the negative stimulus was introduced (whether progressively or abruptly) directly influenced the amount of behavioral contrast produced. This occurred independently of the number of errors made by a pigeon during acquisition of the discrimination. In a series of control experiments, substitution of a red keylight for the dark key during extinction resulted in greater behavioral contrast, while an increase to 3 min in the duration of the green keylight associated with reinforcement attenuated the behavioral contrast

ISSN:0022-5002    

DOI:10.1901/jeab.1976.25-27

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Pigeons were tested in a computer‐controlled two‐key chamber. A standard (nonchanging) schedule of reinforcement was in force on one key, and an adjusting schedule on the other. The schedules were available concurrently after each reinforcement, but after the first peck on either key (the choice peck), the schedule on the other key was made inoperative. The parameter of the adjusting schedule was decreased when the standard schedule was chosen and increased when the adjusting schedule was chosen. The standard schedule was changed only between sessions. Fixed intervals and fixed ratios were used as standard schedules, and intervals and ratios were used as adjusting schedules. When standard and adjusting schedules were of the same type, median parameters on the adjusting key equalled those of the standard schedules, at four values of each standard schedule. For four of five birds, and for the group median, similar curves could be plotted through the indifference points obtained from a standard ratio with an adjusting interval, and from a standard interval with an adjusting ratio. These points showed consistent individual differences, but they could be predicted by assuming that the median time from the choice peck to reinforcement should be the same on both keys. This is equivalent to treating the schedule as a concurrent chain and assuming that Herrnstein's quantitative law of effect appl

ISSN:0022-5002    

DOI:10.1901/jeab.1976.25-43

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Three pigeons pecked for food in an experiment in which each trial consisted of two phases. The first phase consisted of a pattern of three successively illuminated, randomly selected left or right keys. A subject was required to peck each of the lighted keys as they appeared. Thus, in the first phase, a subject emitted a pattern of three left‐ or right‐key pecks. Over trials, all eight possible patterns appeared. A time interval separated the first phase from the second phase, which began with presentation of a randomly selected one of three cues. A reinforcer was delivered in the second phase if a subject pecked the side key that had appeared in the first phase in an ordinal position corresponding to the cue presented in the second phase. That is, the three cues probed a pigeon's memory for the side key it had pecked first, second, or third, in the first phase of a trial. The results show that a pigeon can remember for more than 4 sec the order in which it has just seen and pecked two lighted keys: a pigeon can remember the temporal organization or pattern of events in its recent environment. Consequently, the functional stimulus present when a reinforcer is delivered may include a subject's short‐term memory for the temporal organization of recent events, such as the pattern of its own recent behavior. This possibility is consistent with a molecular analysis of operant behavior focusing on local patterns of beh

ISSN:0022-5002    

DOI:10.1901/jeab.1976.25-55

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

The relation between food deprivation and schedule‐induced attack was investigated in four White Carneaux pigeons. Attack toward a mirror target was induced by a schedule of reinforcement in which 3‐sec food presentations occurred at alternate intervals of 15 and 120 sec (multiple fixed‐time 15‐sec fixed‐time 120‐sec schedule). A continuous tone was presented during the 15‐sec periods; it was absent during the 120‐sec periods. Each pigeon was tested at 65, 80, and 95% of its free‐feeding weight in ascending, descending, and ascending orders, respectively. Two relations were apparent; an inverse relation between body weight and rate of attack, and a tendency for rate of attack to increase during the experiment. Reduction or elimination of attack when the mirror was covered with brown paper for some sessions indicated that the results were due neither to changes in activity that might covary with weight nor to habituation to the exper

ISSN:0022-5002    

DOI:10.1901/jeab.1976.25-63

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

A trio of concurrent variable‐interval schedules of reinforcement was arranged according to a changeover‐key procedure, including a changeover delay of 1.5 sec. The three schedules provided a combined maximum reinforcement rate of 45 reinforcements per hour. With that restriction, the nine experimental conditions included several combinations of variable‐interval schedules, sometimes including extinction. The pigeons matched relative response rate and relative time to relative reinforcement rate. Relative time appeared to match somewhat better than relative response rate. Performance adjusted rapidly from one experimental condition to the next, whether the change involved two or all three schedules of the concurrent

ISSN:0022-5002    

DOI:10.1901/jeab.1976.25-69

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Rats' responses on two levers were reinforced according to independent random‐interval 1.5‐min food schedules. In addition, both lever presses were intermittently punished according to several concurrent random‐interval random‐interval shock schedules. For the left, the scheduled rate of punishment was kept constant according to a random‐interval 6‐min schedule. For the right, the rate of punishment varied. As the frequency of punishment for the right lever press increased, its rate decreased. The rate of the left punished lever press increased, however, even though its scheduled reinforcement rate and punishment rate remaine

ISSN:0022-5002    

DOI:10.1901/jeab.1976.25-75

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Lever pressing by three rhesus monkeys was maintained under a two‐lever concurrent schedule of cocaine reinforcement. Responding on one lever (constant‐dose lever) produced a constant dose of 0.05 or 0.1 mg/kg/injection arranged according to a variable‐interval 1‐min schedule. Responding on the other lever (variable‐dose lever) produced a comparison dose of cocaine (0.013 to 0.8 mg/kg/injection), also under a variable‐interval 1‐min schedule. The two variable‐interval schedules were made nonindependent by arranging that the assignment of a reinforcer by one schedule inactivated the second schedule until the assigned reinforcer had been obtained. This modification ensured that the two cocaine doses were obtained with approximately equal frequency, regardless of the distribution of the subject's responding. Preference, indicated by relative response frequency on the variable‐dose lever, was almost always for the larger of the doses and was a monotonic function of the comparison dose, except at the highest doses. Preferences at the highest comparison doses may have resulted from the low overall response rates exhibited at these doses. Relative response frequencies on the variable‐dose lever roughly matched relative reinforcer magnitude (mg/kg/injection available on the variable‐dose lever divided by the sum of mg/kg/injections ava

ISSN:0022-5002    

DOI:10.1901/jeab.1976.25-81

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY

摘要:

Rates and patterns of key‐press responding maintained under schedules in which responding resulted in intravenous injections of cocaine were studied in squirrel monkeys and rhesus monkeys. Each injection was followed by a 60‐ or 100‐sec timeout period. Schedule‐controlled behavior was obtained at appropriate cocaine doses in each species. Under FR 10 or FR 30 schedules, performance was characterized by high rates of responding (usually more than one response per second) in each ratio. Under FI 5‐min schedules, performance was characterized by an initial pause, followed by acceleration of responding to a final rate that was maintained until the end of the interval. Under multiple fixed‐ratio fixed‐interval schedules, rates and patterns of responding appropriate to each schedule component were maintained. Responding seldom occurred during timeout periods under any schedule studied. At doses of cocaine above or below those that maintained characteristic schedule‐controlled behavior, rates of responding were relatively low and patterns of responding were irregular. Characteristic fixed‐interval responding was maintained over a wider range of cocaine doses than characteristic fixed‐ratio responding. Complex patterns of responding controlled by discriminative stimuli under fixed‐ratio or fixed‐interval schedules can be maintained by cocaine injections in squirrel mon

ISSN:0022-5002    

DOI:10.1901/jeab.1976.25-93

出版商:Blackwell Publishing Ltd    

年代:1976

数据来源: WILEY