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1.
In three experiments, we examined the effect on the patterns of responding noted on fixed interval (FI) schedules of prior
exposure to a range of interval and ratio schedules. Rats leverpressed for food reinforcement on random ratio (RR), random
interval (RI), or variable interval (VI) schedules prior to transfer to FI schedules. In Experiment 1, prior exposure to an
RR schedule retarded the development of typical FI patterns of responding. Exposure to a yoked RI schedule produced even greater
retardation of typical FI performance. This effect was replicated in Experiment 2, using a within-subjects design. Rats responded
on a multiple RR-RI schedule prior to a multiple FI-FI schedule. Typical FI performance emerged more slowly in the component
previously associated with the RI than with that associated with the RR. In Experiment 3, exposure to an RR schedule retarded
the development of FI performance to a greater extent than did exposure to a VR schedule. The latter schedule was programmed
to allow the possibility that inhibitory control would develop after reinforcement. These results confirm that ratio schedules
independently result in the disruption of FI responding. This effect was not long lasting and cannot be used plausibly to
explain species differences in responding to FI schedules. However, it does suggest that temporal control—as manifested by
the transfer of inhibitory control from one schedule to another—could facilitate movement between interval schedules. 相似文献
2.
The experiments reported in the present study tested whether decreasing intertrial intervals (ITIs) intensifies the disruptive
effects of increasing retention intervals (RIs) in a delayed conditional discrimination by decreasing the animal’s trial tracking
accuracy (Cohen & Armstrong, 1996; Cohen & Roberts, 1996). Rats responded on a fixed ratio (FR) 1 or fixed interval (FI) 10-sec
reinforcement schedule at a second light or tone stimulus, S2, when the first light or tone stimulus, S1, had signaled an
FI 10-sec or FR 1 schedule, respectively. RIs between S1 and S2 were increased from 3 to 24 sec and never exceeded ITIs that
were reduced from 24 to 6 sec. For some rats, the trials were separated from each other by extending the lever at S1 and retracting
it at the end of S2 (ITI lever-retracted group). For other, control rats, the lever remained extended throughout the session
(lever-extended group, Experiment 1) or was extended and retracted with the onset and offset of each stimulus (RI/ITI lever-retracted
group, Experiment 2). The rats under all trial conditions learned to delay leverpressing on the FI 10-sec schedule. Latency
to begin leverpressing on the FI 10-sec schedule declined as RIs were increased, but this effect was attenuated in the ITI
lever-retracted groups in both experiments, as would be predicted by thetrial tracking hypothesis. Decreasing ITIs from 24 to 6 sec intensified the disruptive effects of increasing RIs from 3 to 6 sec in the
RI/ITI lever-retracted group (Experiment 2), as would be predicted by the trial tracking hypothesis. 相似文献
3.
In the present experiments, we investigated the effects of mindfulness on behavioral extinction and resurgence. Participants received instrumental training; either they received FI training (Experiment 1), or they were trained to emit high rates and low rates of response via exposure to a multiple VR yoked-VI schedule prior to exposure to a multiple FI FI schedule in order to alter their rates of responding learned during Experiment 2. Participants were then exposed to either a focused- (mindfulness) or an unfocused-attention induction task. All participants were finally exposed to an extinction schedule in order to determine whether a mindfulness induction task presented immediately prior to extinction training affected extinction (Experiment 1) and behavioral resurgence (Experiment 2). During the extinction phase, the rates of responding were higher in the control group than in the mindfulness group, indicating that the mindfulness group was more sensitive to the contingencies and, thus, their prior performance extinguished more readily (Experiment 1). Moreover, rates of response in the extinction components less precisely reflected previous training in the mindfulness group, suggesting less resurgence of past behaviors after the mindfulness induction (Experiment 2). 相似文献
4.
In two experiments, we assessed whether rats optimize the number of reinforcers per response. In Experiment 1, one group of rats was trained to leverpress for food reinforcement on a simple variable-interval (VI) 60-sec schedule. For another group, a negative fixed-ratio component was imposed on the VI schedule to produce a conjoint contingency in which reinforcement became available on the VI schedule but was omitted when the ratio criterion was satisfied. In Experiment 2, one group of rats responded on a VI schedule and also received response-independent food. For another group, responding above a certain rate canceled the response-independent food. Despite the negative contingency experienced by the groups in Experiments 1 and 2, responding was maintained at a level at which the number of obtained reinforcers was reduced substantially below the maximum number possible. In addition, in both experiments, the groups that experienced the negative contingency responded at a lower rate than did a yoked control group that experienced the same frequency of reinforcement but lacked the negative component. These results demonstrate that although rats do not optimize their behavior with respect to reinforcement, they are nevertheless sensitive to some aspect of the instrumental contingency in operation. 相似文献
5.
Phil Reed 《Learning & behavior》2016,44(1):78-84
An experiment examined the impact of a procedure designed to prevent response or extinction strain occurring on random interval schedules with a linear feedback loop (i.e., an RI+ schedule). Rats lever-pressed for food reinforcement on either a RI+ or a random interval (RI) schedule that was matched to the RI+ schedule in terms of reinforcement rate. Two groups of rats responded on an RI+ and two on an RI schedule matched for rate of reinforcement. One group on each schedule also received response-independent food if there had been no response for 60 s, and response-independent food continued to be delivered on an RT-60 schedule until a response was made. Rats on the RI and RI+ obtained similar rates of reinforcement and had similar reinforced inter-response times to one another. On the schedules without response-independent food, rats had similar rates of response to one another. However, while the delivery of response-independent food reduced rates of response on an RI schedule, they enhanced response rates on an RI+ schedule. These results suggest that rats can display sensitivity to the molar aspects of the free-operant contingency, when procedures are implemented to reduce the impact of factors such as extinction-strain. 相似文献
6.
In Experiment 1, rats were allowed to acquire either schedule-induced drinking or schedule-induced wood-chewing behavior under a fixed-interval (FI) 60-sec schedule of food reinforcement, following which food was omitted from 20% and then 50% of interreinforcement intervals. Omission of food severely disrupted induced drinking but had relatively little effect on induced wood-chewing. Experiment 2 investigated wood-chewing as a function of reinforcement rate, using a range of FI schedules from 5 to 180 sec in duration. Both the amount of chewing per session and the relative time spent chewing were bitonically related to reinforcement rate. In Experiment 3, schedule-induced chewing that had been acquired under a response-dependent schedule was found to persist under a response-independent schedule. Induced wood-chewing resembles other induced behaviors in important respects, but quantitative differences are also apparent. 相似文献
7.
Pigeons’ choice responding on 10-sec interpolated probes was studied after baseline training on multiple variable-interval variable-interval schedules of food reinforcement. Unreinforced choice following training with three different relative reinforcement rates (Experiment 1), with a 3-ply multiple schedule (Experiment 2), and with three different relative reinforcement durations (Experiment 3) was examined. Least squares lines were fit to choice relative response rate and schedule relative response rate as functions of training relative reinforcement rate; choice slope was significantly greater than schedule slope in all three experiments. This result is counter to the prediction of Herrnstein’s (1970) theory that these slopes should not differ. Luce’s (1959) theory also failed to account for the data. It was concluded that choice responding was controlled by both approach to the stimulus associated with the smaller mean interreinforcer interval or the longer duration, and avoidance of the other stimulus. 相似文献
8.
We present an algebraic model of resistance to extinction that is consistent with research on resistance to change. The model assumes that response strength is a power function of reinforcer rate and that extinction involves two additive, decremental processes: (1) the termination of the reinforcement contingency and (2) generalization decrement resulting from reinforcer omission. The model was supported by three experiments. In Experiment 1, 4 pigeons were trained on two-component multiple variable-interval (VI) 60-sec, VI 240-sec schedules. In two conditions, resistance to change was tested by terminating the response-reinforcer contingency and presenting response-independent reinforcers at the same rate as in training. In two further conditions, resistance to change was tested by prefeeding and by extinction. In Experiment 2, 6 pigeons were trained on two-component multiple VI 150-sec schedules with 8-sec or 2-sec reinforcers, and resistance to change was tested by terminating the response-reinforcer contingency in three conditions. In two of those conditions, brief delays were interposed between responses and response-independent reinforcers. In both Experiments 1 and 2, response rate was more resistant to change in the richer component, except for extinction in Experiment 1. In Experiment 3, 8 pigeons were trained on multiple VI 30-sec, VI 120-sec schedules. During extinction, half of the presentations of each component were accompanied by a novel stimulus to produce generalization decrement. The extinction data of Experiments 1 and 3 were well described by our model. The value of the exponent relating response strength and reinforcement was similar in all three experiments. 相似文献
9.
We explored response rate as a possible mediator of learned stimulus equivalence. Five pigeons were trained to discriminate
four clip art pictures presented during a 10-sec discrete-trial fixed interval (FI) schedule: two paired with a one-pellet
reinforcer, which supported a low rate of responding, and two paired with a nine-pellet reinforcer, which supported a high
rate of responding. After subjects associated one stimulus from each of these pairs with a discriminative choice response,
researchers presented two new clip art stimuli during a 10-sec FI: one trained with a differential reinforcement of low rate
schedule (DRL) after the FI and the other trained with a differential reinforcement of high rate schedule (DRH) after the
FI. Each of the stimuli that were withheld during choice training was later shown to see if the choice responses would transfer
to these stimuli. The results suggest that response rate alone does not mediate learned stimulus equivalence. 相似文献
10.
In three experiments, we examined the effects of signaling reinforcement during operant responding in order to illuminate the factors underlying instrumental overshadowing and potentiation effects. Specifically, we examined whether signaling reinforcement produces an enhancement and attentuation of responding when the response-reinforcer correlation is weak and strong, respectively. In Experiment 1, rats responded on variable-ratio (VR) or variable-interval (VI) schedules that were equated for the number of responses emitted per reinforcer. A signal correlated with reinforcement enhanced response rates on the VR schedule, but attenuated response rates were produced by the signal on the VI schedule. In Experiment 2, two groups of rats responded on a VI schedule while the two other groups received a conjoint VI, negative fixed-ratio schedule in which the subjects lost the availability of reinforcements if they emitted high response rates. A reinforcement signal attenuated responding for the simple VI groups but not for the animals given the negative fixed-ratio component, although the signal improved response efficiency in both groups. In Experiment 3, a poor correlation between responding and reinforcement was produced by a VI schedule onto which the delivery of response-independent food was superimposed. A signal for reinforcement initially elevated responding on this schedule, relative to an unsignaled condition; however, this pattern was reversed with further training. In sum, the present experiments provide little support for the view that signaling reinforcement enhances responding when the response-reinforcer correlation is weak and attenuates responding when this correlation is strong. 相似文献
11.
Thirty rats received 10 sessions of baseline training in which leverpressing was reinforced according to a variable-interval (VI) 60-sec schedule. Twenty-four of the subjects were then assigned to one of four groups that received five sessions of extinction, with groups being differentiated in a 2 by 2 factorial design on the basis of: (1) changes in stimuli accompanying transportation of subjects from home cages to the laboratory and placement in the apparatus, and/or (2) changes in contextual stimuli within the apparatus. During the sixth session of extinction, the transportational and contextual stimuli previously associated with baseline training were reinstated. The remaining six rats experienced changes in both transportational and contextual stimuli but were maintained on the VI 60-sec schedule of reinforcement. Changes in either transportational or contextual stimuli reduced resistance to extinction and spontaneous recovery, and substantial increments in responding occurred upon reinstatement of the transportational and contextual stimuli associated with baseline training. Evidence for summation of the two sources of stimulus change was obtained. Changes in transportational and contextual stimuli produced only a brief disruption in responding when reinforcement of leverpressing was continued. 相似文献
12.
Schedules of reinforcement typically produce reliable patterns of behaviour, and one factor that can cause deviations from these normally reliable patterns is schizotypy. Low scorers on the unusual experiences subscale of the Oxford-Liverpool Inventory of Feelings and Experiences performed as expected on a yoked random-ratio (RR), random-interval (RI) schedule of reinforcement, with significantly higher rates of responding on the RR schedule than in the RI schedule. However, high scorers in UE showed no such differences between response rates between the RR and RI schedules. In addition, contingency awareness scores were high, and did not differ in low UE scorers for both types of schedule, whilst awareness scores differed significantly between the schedules in high UE scorers, with more awareness of the RR schedule than the RI one. These results suggest that, as well as being unable to differentiate between the RR and RI schedules in terms of response rates, high UE scorers are also unable to verbally describe the RI schedule parameters. 相似文献
13.
After rats were trained on a multiple schedule with variable interval 30-sec reinforcement in both stimulus components, omission, yoked, and extinction procedures were applied in S? while the variable interval continued in S+. In S?, omission training reduced response rate faster and to a lower terminal level than either response-independent yoked reinforcement or extinction, which were approximately equivalent. In S+, the extinction group exhibited elevated response rates representing behavioral contrast, while the omission and yoked groups showed reduced response rates. These results attest to the effectiveness of omission training as a response elimination method. They also contradict theories which posit reduction of response rate in S? to be necessary and sufficient for behavioral contrast. 相似文献
14.
Experiment 1 investigated the behavior of rats trained to leverpress on a concurrent variable ratio (VR) 30 VR-30 schedule with a brief, 500-msec, light occurring at the midpoint of the ratio on one of the levers. Higher response rates were recorded on the lever associated with this stimulus, a finding that paralleled the effect produced by inserting primary reinforcement at the midpoint (i.e., by training on a concurrent VR-30 VR-15 schedule). Similar results were found in Experiment 2 using a concurrent VR-20 VR-20 schedule with a 2-sec visual stimulus presented midway through one of the components. In addition, a brief stimulus inserted midway through the VR-20 component of a concurrent VR-20 VR-10 schedule retarded the development of a difference in response rates between the components relative to a VR-20 VR-10 group lacking the signal. In Experiment 3, multiple VR VR schedules were used. Again, the response rate was higher in the component that had the added stimulus or, for a second group of subjects, on the component with the smaller response requirement. Probe-choice trials revealed a preference for the component that generated the higher rate in both groups. Presenting a stimulus partway through a ratio appears to reduce the effect on response rate and choice of a large ratio value. 相似文献
15.
In each of two experiments, rats were trained to press the lever in a Skinner box, food reinforcement being available on a variable-interval 60-sec schedule (VI 60). There followed an “exposure phase” for which the levers were removed from the boxes, and then a final test with the levers replaced to assess the effects of the intervening treatment on instrumental responding. Experiment 1 showed that simple exposure to the box reduced the vigor of instrumental performance in comparison with a condition in which food was made available during the exposure phase. Animals which received no exposure treatment also showed a relatively high rate of response. Experiment 2 demonstrated that an exposure treatment in which the occurrence of food is signaled by a light stimulus also leads to a decline in instrumental responding. These results are held to support the notion that associations between the context and the reinforcer serve to energize appetitive instrumental behavior. 相似文献
16.
In Experiment 1, 12 rats were exposed to an FT 60 schedule of food reinforcement, followed either by extinction or by a massed-food control condition, in the presence of a wood block. In 9 rats, wood-chewing behavior increased systematically during the FT 60 condition and declined again during extinction or massed food, while the other 3 rats showed virtually no chewing behavior at any stage of the experiment. In Experiment 2, frequency and bout duration of wood-chewing under an FT 60 schedule of food reinforcement declined as body weight increased, in 7 rats. We conclude that wood-chewing qualifies as a schedule-induced behavior, and that it resembles schedule-induced drinking in its dependence on body weight. Unlike drinking, however, induced chewing occupied the middle region of the 60-sec interreinforcement interval, declined markedly within the session, and showed considerable within- and between-subject variability. 相似文献
17.
Pigeons responded in a two-component peak procedure in which the components differed in terms of reinforcement magnitude (Experiment 1), immediacy (Experiment 2), or probability (Experiment 3). The prediction of behavioral momentum theory that responding in the relatively richer component should be more resistant to change was tested by (1) presenting response-independent food in the intervals between components according to a variable-time (VT) schedule, (2) prefeeding, and (3) extinction. In all the experiments, peak location in baseline occurred earlier, relative to the schedule value in the richer component. Peak response rate was more resistant to change in the richer component during the VT and prefeeding tests, and change in peak rate was more sensitive to differential reinforcement than change in overall response rate. Changes in measures of performance on peak trials during the disruptor tests were partially consistent with predictions of the behavioral theory of timing. The results suggest that peak response rate provides a more sensitive index of resistance to change for fixed-interval schedules than does overall response rate and that reinforcement strengthens both peak responding and temporal control. 相似文献
18.
Sated rats, previously trained to leverpress for H2O reinforcement on continuous or variable-interval (10-sec or 60-sec) schedules, were given NaCl injections and tested for leverpressing. Under all schedules, responding was an inverted U function of NaCl concentration (0.15M to 3.0M). However, NaCl thirst produced relatively little change in behavior under the VI 60-sec schedule. 相似文献
19.
Pigeons were studied on multiple variable-ratio yoked-variable-interval schedules in which components had equal rates of food reinforcement and appeared equally often on each of two keys. Interpolated between component changes on the final multiple schedule were 10-sec probes in which both schedule stimuli were present, one on each key. During multiple schedule training, variable-ratio response rates were greater than yoked-variable-interval rates; however, response rate differences in the components were not a function of the mean ratio value for the 40-to-320-ratio range studied. During the choice probes, subjects responded more to the stimulus associated with the interval schedule than to the one associated with the ratio schedule. It was concluded that pigeons prefer interval schedules over equal reinforcement rate ratio schedules, because the former generate fewer responses per reinforcement. 相似文献
20.
Previous experiments on behavioral momentum have shown that relative resistance to extinction of operant behavior in the presence of a stimulus depends on the rate of reinforcement associated with that stimulus, even if some of those reinforcers occur independently of the behavior. We present three experiments examining whether the rate of reinforcement in the presence of a stimulus similarly modulates the relative relapse of operant behavior produced by reinstatement, resurgence, and renewal paradigms. During baseline conditions, pigeons responded for food reinforcement on variable-interval 120-sec schedules in alternating periods of exposure to two stimuli arranged by a multiple schedule. Additional response-independent food presentations were also delivered in the presence of one of the multiple-schedule stimuli. Consistent with previous research, baseline response rates were lower in the presence of the stimulus with the added response-independent reinforcement, and relative resistance to extinction was greater in the presence of that stimulus. In addition, following extinction, the relative relapse of responding produced by reinstatement, resurgence, and renewal paradigms was greater in the presence of the stimulus associated with the higher rate of reinforcement. We suggest that a model of extinction from behavioral momentum theory may be useful for understanding these results. 相似文献