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1.
Contribution of conditioned opioid analgesia to the shock-induced associative US-preexposure deficit
The modulatory effect of conditioned opioid analgesia on learning in the US-preexposure paradigm was examined in three experiments using water-deprived rats. In Experiment 1, it was found that tailflick latencies increased immediately after the rats were exposed to a context in which footshock had previously been administered. Prolonged nonreinforced exposure to the context attenuated this analgesia. Experiment 2 tested the possibility that the effectiveness of CS-US pairings in an excitatory context might be reduced by a conditioned analgesic response that lessens the perceived intensity of the US. Administration of the opiate antagonist naloxone prior to CS-US pairings in the excitatory context reduced the US-preexposure deficit—that is, the retarded response to the CS—but did not eliminate it, suggesting that part of the observed deficit resulted from conditioned activation of the endogenous opioid system. In Experiment 3, it was found that exposure to the excitatory context immediately prior to a CS-US pairing in an associatively neutral context resulted in a conditioned response deficit, indicating that the analgesia elicited by the excitatory context was sufficient to reduce US effectiveness. In combination with other recent reports, these results suggest that the associative deficit resulting from preexposure to a shock US may, in certain instances, represent the sum of several different associative processes. 相似文献
2.
In three experiments using rats as subjects, we investigated the degree to which a conditioned flavor aversion transfers from one context to another. Experiment 1, using a one-trial conditioning procedure, found no effect of a change of context on a conditioned aversion. Experiment 2 employed a multitrial procedure and demonstrated that a conditioned aversion was extinguished more rapidly after a change of context. Experiment 3 showed that context change decreased the effectiveness with which a conditioned flavor could block acquisition of an aversion by a second flavor. It is argued that these data cannot be explained in associative terms, and that they constitute evidence of conditionality in a simple aversive conditioning procedure. 相似文献
3.
Gavan P. McNally Marika C. Gorrisen Lee-fay Low R. Frederick Westbrook 《Learning & behavior》1999,27(4):416-425
Rats were used in four experiments to study the effects on behavior and pain sensitivity of exposure to a context previously
paired with footshock or injection of the emetic drug lithium chloride (LiCl). Exposure to a context previously paired with
footshock or injection of LiCl provoked the species-typical defense response of freezing (Experiments 1A and 1B). Exposure
to a context previously paired with footshock additionally produced hypoalgesia when rats were tested using the tailflick
test (Experiment 1A). By contrast, exposure to a context previously paired with injection of LiCl produced hyperalgesia when
rats were tested using the tailflick test (Experiment 1B). However, exposure to a context previously paired with injection
of LiCl did provoke hypoalgesia when rats were tested for pain sensitivity using either the hotplate or formalin tests (Experiment
2), which was mediated by the release of endogenous opioid peptides (Experiment 3). These results are discussed with reference
to the processes governing associative regulation of defensive behavior and pain control. 相似文献
4.
Three experiments were performed to investigate the learning process underlying the phenomenon of long-delay taste conditioning. An associative model views taste avoidance as due to a conditioned stimulus-unconditioned stimulus (CS-US) associative structure, despite the long interval interposed between the flavor and illness. A nonassociative account of this avoidance behavior posits that avoidance stems from the interaction of two nonassociative processes: habituation of neophobic avoidance to a novel taste, and the poison-induced dishabituation of this process. A postconditioning inflation manipulation was used to discriminate between these two views. It has been demonstrated that enhanced responding with a US inflation manipulation depends, in part, on a previously conditioned association. Therefore, if long-delay taste avoidance arises from nonassociative processes, an inflation manipulation should not affect conditional responding. Experiment 1 demonstrated a delay of reinforcement effect, enhanced avoidance of saccharin in the immediate/inflation group, and no effect of inflation in the delay group and sham controls. Experiment 2 revealed that this differential effect of inflation is not due to absolute differences in the strength of the avoidance response. In Experiment 3, we investigated a potential associative learning mechanism that could account for the differential inflation effect. Together, the present results support the various predictions of a nonassociative account of long-delay taste avoidance. 相似文献
5.
Retention interval effects are seen in taste-aversion learning when single-element aversions are significantly weaker 24 h after conditioning compared with tests at later intervals. This report contains three experiments which suggest that the source of the increased drinking at the 1-day interval is nonassociative interference produced by the novel conditioning episode. In Experiment 1, a parametric analysis demonstrated that aversion strength increased monotonically over a 30-h period following conditioning, and that by 48 h after conditioning it was stabilized. In Experiment 2, a single US preexposure was used to reduce the novelty of the US prior to conditioning. As a result, animals preexposed to the US had stronger taste aversions than did non-preexposed controls at a 1-day retention interval; however, no differences were seen at a 5-day interval. Experiment 3 investigated whether the counterintuitive outcome of Experiment 2 was due to the summation of environment-illness and taste-illness associations at the 1-day test. The results ruled out the summation argument; the US preexposure did not need to be presented in the conditioning context to strengthen the aversion at the 1-day interval. Collectively, these results suggest that the presentation of a surprising US can interfere with the retrieval of the taste-illness association for a short period after conditioning, and that this contributes to the retention interval effect. 相似文献
6.
Rats were exposed to two compound solutions, saline-lemon and sucrose-lemon. In Group ALT, trials with one solution alternated
with trials with the other. Group BLK received all trials with one solution before any trials with the other. Previous retardation
tests had implied that only alternating exposure would establish sucrose as an inhibitor of saline. To provide a complementary
summation test for this inhibition, in Experiment 1, all the animals received pairings of peppermint and saline and were tested
for consumption of peppermint-sucrose under sodium depletion. Consumption was increased by sodium depletion only in Group
BLK. In Experiment 2, a retardation test was used to show that presentation of saline-lemon before sucrose-lemon on each exposure
day would establish sucrose as an inhibitor of saline. Neither exposure to sucrose-lemon before saline-lemon nor alternating
exposure to sucrose and saline alone had the same effect. These results provide support for an associative theory of perceptual
learning that suggests that exposure to complex stimuli aids later discrimination partially as a result of establishing inhibitory
associations between their unique elements. 相似文献
7.
Andrew R. Delamater 《Learning & behavior》1995,23(1):31-39
The outcome-selective effects of presenting intertrial unconditioned stimuli (USs) in a rat appetitive conditioning paradigm were examined in two experiments. In both experiments, two stimuli were paired with different outcomes, while one of these outcomes was also presented in the intertrial interval (A+, B*, +). Two measures of learning, stimulus-elicited magazine approach and Pavlovian-to-instrumental transfer, were used to examine these effects. The presence of freely occurring outcomes in the intertrial interval (ITI) was observed to interfere more with the learning of a new association (Experiment 1) and to degrade more an already established association (Experiment 2) when the conditioned stimulus had been paired with the same outcome as that occurring in the ITI. An outcome-selective effect of ITI USs distinguishes among accounts of contingency based on general performance, attentional, and motivational mechanisms from those based on more specific associative mechanisms. Overall, the data highlight the importance of specific encoding processes in the analysis of associative learning. 相似文献
8.
Most theories of associative learning assert that conditioned responding to a target cue is a monotonically increasing function of unconditioned-stimulus (US) intensity. In a lick suppression preparation with rats, a cue was paired with a 0.4-, 0.6-, 0.8-, 1.0-, 1.2-, or 1.4-mA footshock in Experiment 1a, and with a 0.3-, 0.8-, 1.3-, or 1.8-mA footshock in Experiment 1b. Subsequent suppression in response to the cue was an inverted-U function of the US intensity. In Experiment 2, we demonstrated that massive extinction of the training context and compound conditioning can each attenuate the response decrement caused by training with a high-intensity US. The sometimes-competing-retrieval model (Stout & Miller, Psychological Review 114:759–783, 2007) provides a better fit to these data than do several other models of associative learning. 相似文献
9.
Normally, retention of an avoidance response by a rat is impaired when the test context is novel or does not correspond to the training context. Experiment 1 demonstrates that such an impairment of test performance can be alleviated if a rat receives a cuing treatment or reminder of training in the novel test context prior to testing. Experiment 2 indicates that when rats receive avoidance training in one context and then receive a reminder of training in a novel context, they perform more poorly when tested in the training context than do animals that receive no reminder. This finding is discussed in relation to current theories of contextual influence over retention performance. 相似文献
10.
Rats trained in one context to use stimuli arising from food deprivation as discriminative signals for shock were tested in other contexts to assess the basis of conditioned responding (i.e., freezing or behavioral immobility). In Experiment 1, discriminative control by 24-h food-deprivation cues failed to promote transfer responding in a test context that had no association with shock. This indicated that food deprivation cues had little direct excitatory power. However, transfer of behavioral control by 24-h food-deprivation cues was obtained in a context paired with shock only when the rats were 19 h water deprived. This finding agrees with the idea that food-deprivation cues become conditioned modulators of the capacity of external stimuli to activate their association with an unconditioned stimulus. In Experiment 2, rats trained to use 24-h food-deprivation cues as signals for shock exhibited significantly greater transfer performance when the transfer context had undergone partial extinction relative to when the transfer context had undergone only simple excitatory training. This finding with deprivation cues and transfer contexts (1) paralleled earlier results obtained with discrete (auditory and visual) conditioned modulators and transfer targets, and (2) posed difficulties for associative summation and generalization interpretations of transfer performance. 相似文献
11.
John M. Pearce 《Learning & behavior》1978,6(3):341-345
Three experiments examined the relationship between shock magnitude and the rate of acquisition of a passive avoidance response. Experiment 1 indicated that the use of a relatively large magnitude of shock can disrupt learning to remain on a platform in the center of an open field to avoid shock. The inferior learning of the group trained with high shock was replicated in Experiment 2, which also demonstrated that avoidance learning can occur rapidly with this level of shock if the platform is located in the corner of the apparatus. To explain this, it was proposed that thigmotactic behavior is responsible for the disruption in avoidance behavior when training is conducted in the center with high-magnitude shock. Finally, Experiment 3, essentially a replication of Experiment 1 except that the platform was placed in the corner of the test compartment, demonstrated a direct relationship between shock magnitude and passive avoidance learning. The results are seen as being consistent with accounts which maintain that avoidance learning can be influenced by the occurrence of species-specific defense reactions. 相似文献
12.
A variant of the taste aversion procedure for sensory preconditioning, as used by Rescorla and Cunningham (1978), was employed in a study of the context dependency of within-event learning. In two experiments, rats received Phase 1 exposure to a simultaneous flavor compound, AX; flavor X was paired with illness during Phase 2, and any tendency for the resulting aversion to be elicited by A was measured. It was found that subjects were less likely to shun flavor A as a consequence of this training if the Phase 1 and test episodes were conducted in distinctively different contexts. This effect was evident both when the change of context occurred just before the test with flavor A (Experiment 1) and when it occurred before Phase 2 (Experiment 2). These results were taken to imply that, as is often found with serial associations, the retrieval of within-event associations is subject to contextual control. The implications of these findings for the interpretation of perceptual learning effects are discussed. 相似文献
13.
The present research investigated the effects of physical context change and perceptual learning on generalization. In a video game, participants learned to suppress their mouse-clicking behavior in the presence of one stimulus (AX). Generalization was observed between the AX stimulus and another stimulus (BX) that was designed to be similar. When testing was conducted in a context different from that in which AX was used in training, responding to AX was attenuated, and responding to BX was enhanced. That is, the generalization gradient flattened. The latter effect was only evident in groups for which generalization had been reduced through a preexposure manipulation believed to produce perceptual learning. Experiment 2 demonstrated that the increase in generalization observed in the first experiment was due to the context change between the preexposure and test rather than to a change between the conditioning and test contexts. Implications for flattening generalization gradients and mechanisms of perceptual learning are discussed. 相似文献
14.
This paper begins the exploration of disruption as an analytical construct that allows for the investigation of how individual learning and changes in local practice mutually influence the other within a purposefully designed learning context. We seek to describe the types of learning experiences that emerged using disruptive pedagogies and tools within a series of methods courses in an undergraduate elementary teacher education program. The intent of the designed context was to disrupt the traditional practices of teacher education courses by creating a participatory environment where students participated in the creation of course content through their engagement with social media and each other. We define disruption as an innovation that requires students to challenge or change their epistemologies and participation in their learning. This paper addresses a designed disruption that was created in the context of an elementary methods course. The results demonstrated diverse consequences for participants, their activity, and our understanding of their learning. These findings provide a starting point for examining the implications of disruptive practices within pre-service teacher education programs. 相似文献
15.
Peter C. Holland 《Learning & behavior》2018,46(2):134-156
Prior exposure to a conditioned stimulus (CS) typically results in latent inhibition—slower acquisition of associative learning about that stimulus in subsequent training. Here, we found that CS preexposure had different effects on the appetitive conditioning of rats with a sucrose unconditioned stimulus (US) depending on training test procedures, the similarity of preexposure and training procedures, and the choice of response measure. Preexposure to a visual or an auditory stimulus produced facilitation of acquisition of food-cup-directed responding when both of those cues were (separately) paired with sucrose delivery in the training test (Experiments 1 and 3). By contrast, the same preexposure procedure resulted in latent inhibition of food-cup learning if the second stimulus in the test phase was of the same modality as the preexposed stimulus (Experiment 2). In Experiment 3, latent inhibition was enhanced if both phases included a single CS or both phases included both auditory and visual CSs, compared to treatments in which only one CS was presented in one phase but two CSs were presented in the other phase. In Experiment 4, preexposure of an auditory cue slowed subsequent learning about it if the context was salient but enhanced learning if the context was of weaker salience. Finally, a measure of general activity revealed latent inhibition after preexposure in all conditions in all 4 experiments. We discuss the results within several classes of latent inhibition theories, none of which provides a comprehensive account. 相似文献
16.
In making comparative judgments about pairs of stimuli that are linearly ordered, human subjects usually respond faster the greater the separation between-the-items of a test pair—the symbolic distance effect. A similar result has been obtained for associatively related items, such as the alphabet. We report evidence for a distance effect in monkeys tested with pairs of items drawn from a five-item series with which they had considerable previous experience-in a serial learning setting. This finding provides independent evidence that in learning a serial list of items, monkeys acquire knowledge about the ordinal positions of the items. Analysis of the positive results obtained in Experiment 2 and of the failure to find a distance effect in Experiment 1 suggested that in learning a serial list, monkeys construct both an associative chain representation of the series and a spatial representation, with the latter supplying the spatial markers that convey positional information. This dual coding of sequential events, which may be rather general among mammals, probably supports a variety of cognitive competencies. 相似文献
17.
两个实验采用联结学习范式,分别探讨知觉类别和语义类别材料中,类别感知对特征学习的影响.结果发现,即使是在联结学习范式中,当学习者感知学习材料存在类别时,不仅关注可以有效预测结果的特征,也会关注类别中的其他特征.同时,在知觉类别和语义类别材科中都发现了相同的结果.本实验结果说明,当学习者感知学习材料中存在类别时,即使是在联结学习范式中,学习者也会像类别学习范式中一样,学习额外特征,支持对存在类别的感知,是影响学习者特征学习的重要原因. 相似文献
18.
Studies of extinction in classical conditioning situations can reveal techniques that maximize the effectiveness of exposure-based
behavior therapies. In three experiments, we investigated the effect of varying the intertrial interval during an extinction
treatment in a fear-conditioning preparation with rats as subjects. In Experiment 1, we found less fear at test (i.e., more
effective extinction) when extinction trials were widely spaced, relative to intermediate or massed extinction trials. In
Experiment 2, we used an ABA renewal procedure and observed that spaced trials attenuated renewal of conditioned fear relative
to massed trials. In Experiment 3, we used a similar design, but instead of changing the physical context at the time of testing,
we interposed a retention interval after the extinction treatment to produce a change in the temporal context. The results
showed less spontaneous recovery of fear after spaced than after massed extinction trials. These results suggest that extinction
is more enduring when the extinction trials are spaced rather than massed. Although the benefits of spacing trials are small
when there is no contextual change from extinction to testing, a change in either physical or temporal context following massed
extinction trials leads to a recovery from extinction, which is reduced when the trials are spaced. 相似文献
19.
The effect of a retention interval on latent inhibition was studied in three experiments by using rats and the conditioned taste-aversion procedure. In Experiment 1, we demonstrated an apparent loss of latent inhibition (i.e., a strengthening of the aversion) in preexposed subjects that experienced a retention interval of 12 days between conditioning and the test. In Experiment 2, we found no effect of this retention interval on the habituation of neophobia produced by the phase of exposure to the flavor. In Experiment 3, we showed that interposing a retention interval between preexposure and conditioning produced effects exactly comparable to those seen in Experiment 1. The implications of these results for rival theories of latent inhibition, as an acquisition deficit or as a case of interference at retrieval, are discussed. 相似文献
20.
Prior cuing treatments intended to alleviate the forgetting of a conditioned avexsion-to an odor were tested with 18-day-old rats. Previous experiments had shown that when such pups were conditioned with the use of a CS?/CS+ procedure, pretest presentation of the CS? or US, but not the CS+, alleviated the forgetting otherwise seen after a 3-h retention interval. In Experiment 1, it was determined that the forgetting was not alleviated if the GS? was either preceded or followed by presentation of the CS+, despite the fact that the CS?/CS+ ordering mimicked that of original conditioning. Experiment 2 was an examination of the balance of extinction and reactivation effects caused by presenting the CS+ for varying durations following the 3-h retention interval. The forgetting over this interval was alleviated if the CS+ was presented for 5 or 15 sec, but not 30 sec. With an increase in duration of exposure from 15 to 30 sec, the consequences of the CS+ as a prior cuing treatment apparently shifted from reactivation to extinction. Experiment 3 was a test of the interaction between the consequences of different lengths of CS+ exposure and the effectiveness of adding CS? to the CS+ as a reactivation treatment. The varied effectiveness of reactivation treatments is discussed interms of a change in stimulus conditions from training to reactivation. 相似文献