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1.
Four naive pigeons were given six generalization tests in extinction after periods of pretraining in which S+ appeared with food reinforcement and S? appeared in extinction. An analysis of sequential effects among presentations of test stimuli showed that the overall gradient was influenced differently by stimuli at the extremes of the continuum of test stimuli and by S+ and adjacent stimuli. Gradients consisting of responding in each stimulus when it was preceded by an extreme stimulus tended to peak at S+, while gradients produced when each stimulus was preceded by S+ or an adjacent stimulus tended to show a peak shift. This was true whether the overall gradient showed a peak shift or not. Two naive subjects were added and four additional tests were given after pretraining in which unequal frequencies of reinforcement accompanied both S+ and S?. Results of all 10 tests show that sequential effects occur during generalization testing in extinction and that these “local dimensional effects” are unlike local contrast. These stimulus-specific sequential effects may greatly influence overall gradient form. 相似文献
2.
Pigeons’ responses on an operant key were reinforced according to either multiple variable-interval variable-interval or multiple variable-interval extinction schedules. The multiple-schedule components were signaled by line-tilt stimuli on a second key (signal key). Signal-key responses never produced reinforcement, and operant-key responses were not reinforced if they followed within 1 sec of a signal-key response. Behavioral contrast was not observed on the operant key, although there was a small, but reliable, increase in signal-key responding in the variable-interval component of the multiple variable-interval extinction condition. Generalization tests were interspersed between sessions of multiple variable-interval extinction training. Generalization gradients along the line-tilt dimension exhibited peak shift for both operant-key and signal-key responding following intradimensional (line tilt) discrimination training. Line-tilt generalization gradients following interdimensional discrimination did not exhibit peak shift. Gradients following intradimensional discrimination were sharper than gradients following interdimensional discrimination for both operant-key and signal-key responding. It was concluded that dimensional stimulus control of topographically tagged responding maintained by the stimulusreinforcer relation parallels that maintained by the response-reinforcer relation. 相似文献
3.
James V. Couch 《Learning & behavior》1975,3(4):347-358
Two experiments examined the presumed relationship between behavioral contrast and inhibitory stimulus control. In Experiment I, pigeons were exposed to mult VI 1-min VI 1-min or mult VI 5-min VI 5-min during baseline training prior to mult VI 1-min VI 5-min discrimination training. Half of the subjects received a timeout (TO) component during baseline in order to reduce the degree of contrast during discrimination training. Only 3 of 8 subjects receiving the TO showed contrast while all other subjects showed various degrees of contrast. Postdiscrimination generalization gradients indicated excitatory rather than inhibitory control by the stimulus associated with the VI 5-min schedule. During baseline training in Experiment II, responding to all the generalization stimuli was reinforced. In addition, some subjects received the TO stimulus. The subjects were next exposed to mult VI 1-min EXT, mult VI 1-min VI 5-min, or just the VI 5-min component. Generalization gradients indicated inhibitory control by the stimulus associated with EXT or VI 5-min for 19 of 20 subjects even though some subjects did not show contrast. These results question the presumed relationship between behavioral contrast and inhibitory stimulus control. 相似文献
4.
Rats were trained on a multiple variable-interval extinction schedule of reinforcement. The effects of a stimulus which preceded an unavoidable shock were assessed when it was superimposed on both components of the schedule or on VI components only. In general, VI responding was suppressed during the preshock stimulus. There was no evidence for any increase in responding during extinction components either generally or differentially during the preshock stimulus. These findings fail to support an earlier suggestion that a preshock stimulus may impair discrimination performances. 相似文献
5.
Guy Woodruff 《Learning & behavior》1979,7(3):339-346
Groups of pigeons were exposed to multiple variable-interval variable-interval and multiple variable-interval extinction schedules of either food or water reinforcement for keypecking. Discriminative stimuli associated with component schedules were located either on the operant key or on a second “signal” key. When the stimuli were projected on the operant key, positive contrast appeared during discrimination conditions with either food or water as the reinforcer. When the stimuli were projected on the signal key, overall responding to the operant and signal keys showed contrast with food, but negative induction with water as the reinforcer. In the latter condition, the signal for the variable-interval shcedule of water reinforcement elicited a variety of water-related behavior, only some of which was directed at the signal. Thus, the type of reward and location of discriminative stimuli interacted to determine the presence or absence of behavioral contrast effects. In large part, these results support and extend the autoshaping view of contrast. 相似文献
6.
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
7.
K. Geoffrey White 《Learning & behavior》1973,1(4):297-301
Following 20 sessions of variable-interval 20-sec reinforcement in the presence of a single 45-deg line-tilt stimulus, three pigeons were trained to discriminate between line tilts of 45 deg correlated with variable-interval 20-sec reinforcement and line tilts of 15 deg correlated with extinction. A generalization test along the line-tilt dimension was administered following a criterion discrimination performance. Gradients derived in terms of relative frequency of response as a function of line tilt indicated strong external stimulus control and exhibited clear peak shift. From the interresponse time (IRT) distributions generated for responding to each test stimulus, probability of response conditional upon IRT (IRTs/Op) was derived as a joint function of line tilt and IRT. The IRTs/Op functions for responses following IRTs in 0.2-sec-wide classes from 0.2 to 1.0 sec and for responses following IRTs in the interval of 1.0 to 2.0 sec were similar to the relative generalization gradients and also exhibited peak shift. Few IRTs were greater than 2.0 sec. External stimulus control was established over responses terminating IRTs both longer and shorter than 1.0 sec. 相似文献
8.
Three experiments demonstrated that, following the extinction of an established conditioned stimulus (CS; e.g., tone), the
pairing of an orthogonal stimulus from another modality (e.g., light) with the unconditioned stimulus (US) results in strong
recovery of responding to the extinguished CS. This recovery occurred to about an equal degree regardless of whether or not
initial training contained unambiguous stimulus—reinforcer relationships—that is, consistent CS—US pairings—or some degree
of ambiguity, including intramodal discrimination training, partial reinforcement, or even cross-modal discrimination training
(tone vs. light). Experiments 1 and 2 demonstrated that this recovery of responding was largely specific to the extinguished
CS, but moderate generalization to other stimuli from the same modality did appear. The results are discussed with reference
to alternative mechanisms applicable to learning-dependent generalization between otherwise distinct CSs. These models assume
that such generalization is mediated by either a shared response, shared reinforcer, shared context, or shared hidden units
within a layered neural network. A specific layered network is proposed to explain the present results as well as other types
of savings seen previously in conditioning of the rabbit nictitating membrane response. 相似文献
9.
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
10.
Blough DS 《Learning & behavior》2004,32(2):157-172
In three experiments with pigeons, the similarity of unreinforced test stimuli to a reinforced stimulus and the frequency
of reinforcement associated with a stimulus were varied. The stimulus on each trial was a small spot that appeared in different
hues or, in Experiment 3, different forms. Differential response frequency and reaction time (RT) patterns emerged: Changes
in similarity affected the percentage of stimuli responded to but left the shape of RT distributions about the same, whereas
changes in reinforcement shifted RT distributions but had little effect on the percentage of responses. When the similarity
and reinforcement variables were applied to the same stimuli (Experiment 2), their effects were largely independent. A generalization
procedure (Experiment 3) replicated the similarity effects of the initial discrimination procedure. The RT distributions were
modeled by a diffusion process, and implications for a memory-instance model were suggested. 相似文献
11.
The similarity in the discrimination training leading to behavioral contrast and that preceding tests producing response enhancement to combined discriminative stimuli suggested that the two phenomena might be related. This was investigated by determining if contrast indiscrimination training was necessary for this outcome of stimulus compounding. Responding to tone, light, and to the simultaneous absence of tone and light (T + L) was maintained during baseline training by food reinforcement in Experiment I and by shock avoidance in Experiment II. During subsequent discrimination training, responding was reduced in T + L by programming nonreinforcement in Experiment I and safety or response-punishment in Experiment II. In the first experiment, one rat exhibited positive behavioral contrast, i.e., tone and light rates increased while his T + L rate decreased. In Experiment II, rats punished in T + L showed contrast in tone and light, this being the first demonstration of punishment contrast on an avoidance baseline with rats. The discrimination acquisition data are discussed in the light of current explanations of contrast by Gamzu and Schwartz (1973) and Terrace (1972). During stimulus compounding tests, all subjects in both experiments emitted more responses to tone-plus-light than to tone or light (additive summation). An analysis of the terminal training baselines suggests that the factors producing these test results seem unrelated to whether or not contrast occurred during discrimination training. It was concluded that the stimulus compounding test reveals the operation of the terminal baseline response associations and reinforcement associations conditioned on these multicomponent free-operant schedules of reinforcement.
相似文献12.
13.
Behavior reduced as a consequence of extinction or intervention can relapse. According to behavioral momentum theory, the extent to which behavior persists and relapses once it has been eliminated depends on the relative training reinforcement rate among discriminative stimuli. In addition, studies of context renewal reveal that relapse depends on the similarity between the training stimulus context and the test stimulus context following disruption by extinction. In the present experiments with pigeons, we arranged different reinforcement rates in the presence of distinct discriminative stimuli across components of a multiple schedule. Following extinction, we attempted to reinstate responding in the presence of those target components with response-independent food presentations. Importantly, we arranged the reinstating food presentations either within the target components or in separate components, either paired with extinction (Experiment 1) or reinforcement (Experiment 2) during baseline. Reinstatement increased with greater training reinforcement rates when the reinstating food presentations were arranged in the target components and the separate components paired with reinforcement during training. Reinstatement was smaller and was not systematically related to training reinforcement rates in the target components when reinstating food presentation occurred in separate components paired with extinction. These findings suggest that relapse depends on the history of reinforcement associated with the discriminative stimuli in which the relapse-inducing event occurs. 相似文献
14.
Resurgence is the recurrence of a previously reinforced and then extinguished behavior induced by the extinction of another more recently reinforced behavior. Resurgence provides insight into behavioral processes relevant to treatment relapse of a range of problem behaviors. Resurgence is typically studied across three phases: (1) reinforcement of a target response, (2) extinction of the target and concurrent reinforcement of an alternative response, and (3) extinction of the alternative response, resulting in the recurrence of target responding. Because each phase typically occurs successively and spans multiple sessions, extended time frames separate the training and resurgence of target responding. This study assessed resurgence more dynamically and throughout ongoing training in 6 pigeons. Baseline entailed 50-s trials of a free-operant psychophysical procedure, resembling Phases 1 and 2 of typical resurgence procedures. During the first 25 s, we reinforced target (left-key) responding but not alternative (right-key) responding; contingencies reversed during the second 25 s. Target and alternative responding followed the baseline reinforcement contingencies, with alternative responding replacing target responding across the 50 s. We observed resurgence of target responding during signaled and unsignaled probes that extended trial durations an additional 100 s in extinction. Furthermore, resurgence was greater and/or sooner when probes were signaled, suggesting an important role of discriminating transitions to extinction in resurgence. The data were well described by an extension of a stimulus-control model of discrimination that assumes resurgence is the result of generalization of obtained reinforcers across space and time. Therefore, the present findings introduce novel methods and quantitative analyses for assessing behavioral processes underlying resurgence. 相似文献
15.
In Experiment 1, it was shown that generalization testing following successive discrimination training between two closely spaced wavelengths results in a sharp gradient with a peak of responding shifted from S+ so as to be further removed from S?. Testing after a 24-h delay resulted in a flatter gradient with greater peak (and area) shift. A 5-min pretest exposure to S+, reinforced or unreinforced, or to S? (unreinforced) reinstated immediate test performance; free reinforcement with no discriminative stimulus present had no such effect. Experiment 2 replicated the flattening of generalization gradients and enhanced peak shift in delayed testing. Free feeding in a pretest treatment with a distinctive food uniquely associated with the wavelength discrimination problem failed to reinstate immediate test performance. Experiment 3 tested the hypothesis that free feeding failed as a reactivation treatment because it did not engender keypecking. Subjects were trained to peck a vertical line stimulus before being given wavelength discrimination training. Again, the enhanced peak shift and greater flattening with delayed wavelength generalization testing was found. A pretest exposure to the vertical line stimulus elicited pecking but had no effect on subsequent wavelength generalization. Thus, only a reactivation treatment that included one of the discrimination training stimuli was effective in producing delayed test performance comparable to that obtained in an immediate test. 相似文献
16.
Ralph W. Richards 《Learning & behavior》1979,7(3):309-312
Pigeons were trained on a conditional discrimination in which responding was reinforced either in the presence or in the absence of a vertical line, depending on the color of the key and the chamber’s illumination. When subsequently tested for generalization along the line-orientation dimension, all subjects showed a decremental gradient when the Unes were combined with the color that had signaled reinforcement in the presence of the vertical line. In addition, most subjects showed an incremental gradient when the lines were combined with the color that had signaled no reinforcement in the presence of the vertical line. 相似文献
17.
Two experiments were performed to determine whether the location of the discriminative stimuli affects the amount of positive behavioral contrast exhibited during discrimination learning by pigeons. When signals for reinforcement and nonreinforcement of keypecking were situated directly on the response key (different line tilts), pecking rates during the positive stimulus were higher than when the source of the signals was located elsewhere (changes in chamber illumination or auditory click frequency). These results are in general agreement with the additivity theory of behavioral contrast, which attributes contrast to the combined effects of stimulus-reinforcer and response-reinforcer correlations on behavior directed at signals of reinforcement. Some shortcomings of the theory were discussed, and the notion that behavioral contrast is a basic, unitary phenomenon was criticized. 相似文献
18.
The present experiment compared two methods of eliminating a classically conditioned response in dogs, extinction and reinforcement of nonsalivation, using both a within- and between-subjects experimental design. Eighteen dogs were trained for 16 days in Phase I, 16 days in Phase II, and 8 days in Phase III. In Phase I, each subject received classical conditioning training to two stimuli. In Phase II, Group 1 received extinction training to one stimulus and reinforcement of nonsalivation to the other stimulus. Group 2 received continued classical conditioning training to one stimulus and reinforcement on nonsalivation training to the other. Group 3 received continued classical conditioning training to one stimulus and extinction training to the other. In both the within- and between-subjects comparisons, responding to the stimulus associated with extinction was eliminated faster than responding to the stimulus associated with reinforcement of nonsalivation. 相似文献
19.
Donald E. McMillan 《Learning & behavior》1989,17(1):113-117
Discriminative stimuli produced by drugs control behavior in the same way as exteroceptive discriminative stimuli control behavior, despite the difficulty in controlling the intensity of the discriminative stimulus properties of drugs throughout test sessions. In recent years, many investigators have correlated the potency of drugs as discriminative stimuli, with their affinity for specific pharmacological receptors. High correlations have been interpreted as evidence that the discriminative stimulus properties of drugs are mediated by these specific pharmacological receptors. However, the relationship between discriminative stimulus potency and receptor affinity can be confounded by other pharmacological effects of drugs, such as their ability to produce position responding, and by behavioral variables, such as the schedule of reinforcement under which the drug discrimination is established and measured. 相似文献
20.
Andrew R. Delamater 《Learning & behavior》1996,24(4):437-449
Pavlovian-to-instrumental transfer tests were used to assess the sensitivity of Pavlovian stimulus-outcome (S-O) associations to various extinction treatments in four appetitive conditioning experiments with rats. In Experiment 1, simple nonreinforcement of a stimulus was shown to have little impact on the ability of that stimulus to display outcome-specific transfer of control. Extinguishing a stimulus by pairing the stimulus with an alternative reinforcement in Experiment 2 also had no detectable effect on the S-O associations as assessed with the outcome-specific transfer measure. The third and fourth experiments, respectively, examined the impact of postconditioning exposures to random and explicitly unpaired S-O contingencies upon previously learned S-O associations. These treatments, as well, had no detectable harmful effects upon the integrity of the S-O associations. In contrast to the consistent failures of various extinction treatments to influence the ability of stimuli to display outcome-specific transfer, these treatments often did reduce the strength of conditioned responding initially trained to these stimuli. These results support the view that extinction entails the preservation of S-O associations as well as the parallel development of inhibitory stimulus-response associations. Other notions of extinction are also discussed. 相似文献