共查询到20条相似文献，搜索用时 62 毫秒
1.
In two experiments, the hypothesis that frustration mediates the production of schedule-induced polydipsia was tested. In Experiment I, a group in which reward was reduced from 6 to 2 pellets of food in an operant chamber was found to increase water intake compared to a group maintained at 2 pellets reward. In Experiment II, rats trained to approach food on a partial reinforcement schedule in a runway subsequently showed lower levels of water intake in the operant test for polydipsia than rats given continuous reinforcement during runway training. The results are interpreted as supporting a frustration hypothesis of schedule-induced polydipsia and are discussed within the context of persistence theory. 相似文献
2.
In Experiment I rats were trained for 21÷2 days under partial (PRF) or continuous reinforcement (CRF) conditions starting at 18, 22, 28, or 36 days of age and were then subjected to immediate extinction. At all ages there was a strong partial reinforcement extinction effect (PREE), and absolute size of PREE was greatest in the youngest rats. Rate of extinction increased as a function of age following both CRF and PRF. In Experiment II the youngest and oldest age groups of Experiment I were run under the two reward conditions of Experiment I and in a third condition, PRF with number of rewards rather than trials equated to CRF (PRF-R). The PRF-R and PRF groups were not different in extinction, and both were more persistent than CRF. The youngest rats were again more persistent than the oldest, particularly after PRF training. In Experiment III it was shown that the well-known paradoxical effect, greater reward in CRF acquisition leads to faster extinction, operates in our youngest and oldest animals, but is more pronounced in the oldest. The results are discussed in terms of whether they require different explanations than those often applied to extinction data from adult rats. 相似文献
3.
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
4.
Patricia D. Stokes 《Learning & behavior》1995,23(2):164-176
Potential contributors to sustained levels of variability in the topography of the rat’s barpress were investigated in two experiments. Behavior was classified into discretely defined components, and changes in components and their sequential organization were analyzed. Experiment 1 showed that topographic variability in the rat is modulated by shifts in reinforcement schedules. Variability decreased between either dipper training or extinction and continuous reinforcement (CRF), and increased between CRF and extinction. Once the press was acquired, variability did not change if the schedule (CRF) did not change. Experiment 2 showed that, regardless of subsequent changes in topographic requirements, rats initially shaped to press under more stringent criteria sustained higher levels of variability during CRF, but not during extinction, than rats shaped with less stringent criteria. The results suggest that subjects learn not only what to do during reinforcement but also how differently or variably to do it. 相似文献
5.
Masato Ishida 《Learning & behavior》1986,14(3):293-300
When extinction is delayed very long, the superior resistance to extinction of the random schedule group relative to the alternating schedule group disappears (partial reinforcement delayed extinction effect, PRDE). Two experiments assessed the effects of reinforcement/nonreinforcement on Trial 1 on the PRDE. Following extended partial reinforcement acquisition training in a runway, rats received extinction training after a short (1-day) or long (23-day) retention interval. The schedules used in Experiment 1 were: a single-alternation (SA) schedule beginning each day with a rewarded (r) trial, for Group r-SA; an SA schedule beginning with a nonrewarded (n) trial, for Group n-SA; and a random (Rd) schedule, for Group Rd. The schedules and group names used in Experiment 2 were r-SA, Rd, and r-Rd. The results were that (1) rats given r-SA schedules yielded considerable resistance under delayed extinction, (2) those given Rd and r-Rd schedules showed a decline in resistance to extinction over a long retention interval, (3) those given the n-SA schedule showed relatively low resistance at both retention intervals, although retention deficit was not greater than in the case of the Rd schedule, and thus, (4) the PRDE was found in both experiments, although only weakly in Experiment 1. The results indicated that a regularly alternating reward pattern was a more important determinant than was type of reward on Trial 1 for the PRDE. The PRDE due to differential retention deficits among schedules is discussed on the basis of dual-process associative sequential mechanisms and cognitive rule-encoding mechanisms. 相似文献
6.
Animals exposed to schedules of partial reinforcement are typically more resistant to extinction than are animals trained with continuous reinforcement. This is the partial reinforcement effect (PRE). Animals experienced with both partial and continuous schedules are often more persistent on the continuous schedule, yielding a reversed PRE. Both conventional and reversed PREs have been elusive with classical conditioning paradigms. The present experiment attempted to demonstrate between- and within-subject PREs using 50% and 100% autoshaping schedules. Presence or absence of a PRE depended on the behavioral measures used. Marked terminal group differences in acquisition produced a between-subjects PRE with absolute response levels but not with rate-of-change measures. Within subjects, only choice trial comparisons were sensitive enough to differentiate the two schedules. Acquisition data were inconsistent with most of the classical conditioning PRE literature, but consistent with results reported in the autoshaping literature. These discrepancies may reflect the operant-classical interaction in autoshaping. 相似文献
7.
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
8.
In Experiment 1, rats were trained to leverpress on a variable ratio (VR) 30 schedule with a 500-msec delay between the reinforced response and food delivery. Subjects that experienced a signal during the delay responded faster than did control subjects that received the stimulus un-correlated with reinforcement. Higher response rates were obtained when the stimulus used to signal reinforcement was auditory rather than visual. Experiments 2 and 3 compared the effects of signaling reinforcement with either a localized or a diffuse light on responding maintained by VR schedules of reinforcement. Elevated response rates were observed with the diffuse stimulus, but the localized stimulus failed to produce such potentiation. Experiment 3 also examined the conditioned reinforcing power of localized and diffuse visual stimuli. These results are discussed with reference to (1) theories of selective association and sign tracking and (2) their implications for current theories of signaling reinforcement. 相似文献
9.
In four experiments with rats, we examined the persistence of behavior when reinforcement was switched from immediate to delayed.
In Experiment 1, lever pressing elicited by instrumental training with immediate reinforcement continued when a 20-sec delay
of reinforcement was introduced (easy-to-hard condition), whereas when the delay condition was introduced from the start (hard-to-hard
condition), responding remained low throughout. A similar result was obtained in Experiment 2, in which lever pressing was
elicited by a classical conditioning (autoshaping) procedure. In Experiment 3, rats initially trained with delayed reinforcement
continued to respond at a low rate when switched to immediate reinforcement (hard-to-easy condition). By measuring magazine
entry (goal tracking) as well as lever pressing (sign tracking) in Experiment 4, we confirmed that such transfer effects at
least partly involve the persistence of whatever type of behavior was initially dominant. 相似文献
10.
In Experiment 1, four groups of rats were initially trained on a discrimination which established a stimulus as a signal for reinforcement. That signal was then presented during subsequent partial reinforcement training in a way that could potentially interfere with retrieval of the memory of nonreinforcement (SN) on the preceding trial either because (1) thestorage and retrieval contexts for SN were different (retrieval failure hypothesis), or (2) the memory of reinforcement produced by the signal acted as a competing memory (competing memory hypothesis). Experiment 1 supported the competing memory hypothesis. In Experiment 2, we investigated the effect of stimulus change on the capacity of the context to retrieve a competing memory of a temporally remote reinforcement event with which the context was strongly associated. Retrieval of a competing memory was impaired by differences between the storage and retrieval contexts in a manner analogous to the effect of context on retrieval of a reinforcement event memory from an immediately preceding trial. 相似文献
11.
Scott H. Deibel Matthew L. Ingram Andrew B. Lehr Hiliary C. Martin Darlene M. Skinner Gerard M. Martin Isaac M. W. Hughes Christina M. Thorpe 《Learning & behavior》2014,42(3):246-255
It is difficult for rats to acquire daily time–place (TP) learning tasks. One theory suggests that rats do not use time of day as a stimulus signaling a specific response. In the present study, we tested rats’ ability to use time of day as a discriminative stimulus. A fixed-interval procedure was used in which one lever provided reinforcement on a FI-5-s schedule in morning sessions, and the same lever provided reinforcement on a FI-30-s schedule in afternoon sessions. Because only one place was used in this paradigm, the rats could only use time of day to acquire the task. Mean responses during the first 5 s of the first trial in each session indicated that the rats did not discriminate between the two sessions. In Phase II, a different lever location was used for each of the two daily sessions, which meant that both spatial and temporal information could be used to acquire the task. The rats readily acquired the task in this phase, and probe trials indicated that the rats were using a combination of spatial and temporal information to discriminate between the two different trial types. When the spatial cue was removed in Phase III, rats no longer discriminated the two sessions, suggesting that time can only be used as a discriminative stimulus when each daily session is associated with a distinct spatial location. 相似文献
12.
Two experiments were run in order to investigate the influence of external contextual cues on the interaction between two conflicting memories. Rats were trained, in the same apparatus, on a passive-avoidance task and, 10 min later, on an active-avoidance task, then submitted to a 24-h delayed test (without reinforcement). When contextual cues remained unchanged throughout these three phases, the animals exhibited proactive interference, as shown by longer response latencies than those of control animals that had learned only the active-avoidance task (Experiment 1). When training contexts were made slightly different from one task to the other (by the presence of a continuous tone during either the first or the second task), the animals behaved at subsequent testing in accordance with the response contingencies present in the context exactly similar to the test context; this control of behavior by testing context was demonstrated both when the tone was absent (Experiments 1 and 2) and present (Experiment 2) at testing. A cuing procedure—a 90-sec exposure to the tone in the experimental room 5 min prior to testing—led the animals to behave in accordance with the response previously acquired in the presence of the tone (Experiments 1 and 2), exactly in the same way as animals tested in the presence of the tone (Experiment 2). The same cuing treatment was ineffective when administered 1 h before testing (Experiment 2). These results are interpreted in terms of a dual function of contextual cues at the time of retrieval: the general contextual information present during testing or during pretest cuing is assumed to induce concurrent reactivation of both memories. Consequently, the experimentally manipulated contextual cue (the tone) would have a discriminative function, leading the animals to choose between the two equally available representations. 相似文献
13.
In four experiments, rats were trained on different patterning discriminations before being tested with compounds composed of novel combinations of the trained stimuli. In Experiment 1, rats were trained on a negative-patterning schedule (A+ B+ AB-) intermixed with reinforced presentations of a second compound (CD+). On a subsequent test, the rats responded more to two novel compounds, AC and BD, than to A and B, but less than to CD. In Experiment 2, rats were trained on two concurrent negative-patterning discriminations (A+ B+ AB-, C+ D+ CD-). On test, they responded more to AC and BD than to AB and CD, but less than to the single stimuli. In Experiment 3, rats were trained on two concurrent positive-patterning discriminations (A-B- AB+, C- D- CD+). On test, their response rates to AC and BD were not different from the response rates to the trained compounds (AB and CD). Finally, in Experiment 4, rats were trained on a positive- and negative-patterning discrimination concurrently. Once again, on test, response rates to AC and BD were not different from responding on reinforced trials of the trained discriminations (A+, B+, and CD+). We discuss the implications of these findings for elemental and configural models of stimulus representation. 相似文献
14.
Steven J. Haggbloom 《Learning & behavior》1980,8(3):424-428
In two differential conditioning experiments, groups of 10 rats each differed with respect to average reward and schedule of reward received in S+. Nonreward (N) occurred on all S? trials. In both experiments, extinction of responding to S? (resistance to discrimination) was extensively regulated by reward sequence and was largely independent of average reward. In Experiment 1, resistance to discrimination was a function of transitions from N to rewarded (R) trials (N-R transitions). In Experiment 2, resistance to discrimination was increased by large reward on the R trial of N-R transitions and decreased by large reward on the R trial of R-N transitions. These schedule effects on resistance to discrimination parallel the effects of comparable schedules on resistance to extinction following partial reinforcement. The results are discussed in terms of sequential theory, reinforcement level theory, and their implications for various schedule manipulations that have previously shown S? behavior to be inversely related to average reward in S+. 相似文献
15.
Dave G. Mumby Tom J. Kornecook Emma R. Wood John P. J. Pinel 《Learning & behavior》1995,23(4):447-453
Two experiments assessed whether odors left on stimulus objects by experimenters who handle them might confound the interpretation of ostensibly visually guided object-memory tasks for rats. In Experiment 1, rats were able to discriminate the relative recency with which an experimenter touched two otherwise identical objects (intertouch interval = 4 sec), presumably on the basis of an odorintensity discrimination. However, after the rats mastered the odor discrimination with no delay between when the second of the two stimulus objects was last touched by the experimenter and when the rats were permitted to attempt the discrimination, their performance dropped to chance levels when this delay was increased to 15 sec. In Experiment 2, rats were trained in two slightly different ways to perform a delayed-nonmatching-to-sample (DNMS) task, one that involved systematic differences in the temporal order in which the experimenter handled the sample and novel stimulus objects and one that did not. There were no significant differences in the rate at which rats mastered the DNMS task with these two procedures, and the performance of rats that were trained according to the former procedure was unaffected when they were switched to the latter procedure. Moreover, rats required considerably fewer trials to master the DNMS task than the rats in Experiment 1 required to master the odor discrimination. These findings demonstrate that, under certain circumstances, rats can discriminate the relative recency with which two objects are handled by an experimenter, but that this ability contributes little to their performance of conventional object-based DNMS tasks. 相似文献
16.
Rats were trained to leverpress for food and subsequently exposed to either arithmetic series or random variable-interval reinforcement schedules. Adjunctive drinking developed in all subjects exposed to arithmetic variable-interval reinforcement, but did not develop in six of the eight animals trained on the random schedule. The results suggest that adjunctive drinking is the result of an interaction between the tendency of rats to drink after eating and the ability of locally low probabilities of reinforcement within schedules to induce conditioned behavioral states. 相似文献
17.
Robert A. Rosellini 《Learning & behavior》1978,6(2):155-159
This article reports the reinforcer generality of the interference effect resulting from exposure to inescapable shock. In Experiment 1, rats that received inescapable shock showed weak interference with the acquisition of an appetitive operant compared to animals exposed either to escapable or no shock. In Experiment 2, the response-reinforcer contingency was degraded by introducing a 1-sec delay of reinforcement on the appetitive task. Inescapable shock produced much stronger interference with the acquisition of the operant response than in Experiment 1. The results demonstrate reinforcer generality of the debilitating effects produced by inescapable shock. 相似文献
18.
In three experiments, we examined the effect of response-outcome relations on human ratings of causal efficacy and demonstrated
that such efficacy ratings transfer to novel situations through derived stimulus relations. Causal efficacy ratings were higher,
and probability of an outcome given a response was lower, for a differential reinforcement of high rate schedule than for
either a differential reinforcement of low rate schedule (Experiment 1) or a variable interval schedule (Experiment 2). In
Experiment 3, we employed schedules that were equated for outcome probability and noted that ratings of causal efficacy and
the rate of response were higher on a variable ratio than on a variable interval schedule. For participants in all three experiments,
causal efficacy ratings transferred to the stimulus present during each schedule and generalized to novel stimuli through
derived relations. The results corroborate the view that schedules are a determinant of both response rates and causal efficacy
ratings. In addition, the novel demonstration of a mechanism of generalization of these ratings via derived relations has
clinical implications. 相似文献
19.
In Experiments 1 and 2, rats were trained in a Morris water maze to locate a hidden platform, the location of which in the circular pool was defined by four visual landmarks (A, B, C, and D), spaced at equal intervals around the edge of the pool. Control animals were trained with these four visual landmarks only. But for animals in the overshadowing groups, an auditory component, X, was added to Landmark D. Test trials, given at the end of training, consisted of placing the rat in the pool with no platform present and recording the time rats spent in the platform quadrant. In Experiment 1, the overshadowing group spent less time in the platform quadrant than controls when tested with D, but the two groups performed equally well on test trials that did not use D. We conclude that the auditory Component X overshadowed the visual Landmark D. In Experiment 2, we obtained evidence of reciprocal overshadowing, of D by X and of X by D. The results of Experiment 3 suggested that an appeal to generalization decrement might not be sufficient to explain these overshadowing effects. 相似文献
20.
The influence of cue type and cue configuration on radial-maze performance in rats was examined in two experiments. In the first experiment, it was found that rats provided with both salient intramaze and extramaze cues acquired the task faster than rats given only one set of cues. No difference in acquisition was found between a group trained with intramaze cues alone and a group trained with extramaze cues alone. In a cue-preference test, it was found that groups that had been trained with extramaze cues, intramaze cues, or both sets of cues relied on extra-maze cues to avoid visited arms when given both types of cues concurrently. When all groups were transferred to intramaze-cue-alone trials, only the group that had been originally trained with extramaze cues alone showed any disruption. Also, during the second half of the intramaze-cue-alone trials, the arrangement of these cues was randomly changed on each trial. This disruption in cue configuration did not deleteriously affect performance in any of the three groups; all remained above chance performance, although the performance of the group originally trained with extramaze cues alone was inferior to that of the other two groups. In Experiment 2, groups of rats were trained on daily alternating trials under intramaze-cue-alone and extramaze-cue-alone conditions. For one group, the configuration of intramaze cues was altered randomly on each trial; the other group had intramaze cues always presented in the same configuration over trials. It was found that acquisition was more rapid on intramaze trials in the group given static configurations. Also, acquisition of the extramaze task was faster than the intramaze task in the group given variable intramaze cue configurations. No difference was found between the intramaze and extramaze conditions in the group given static intramaze cue configurations. These data suggest that a static cue configuration may influence radial maze performance, but is not a necessary condition for such performance. 相似文献