共查询到20条相似文献，搜索用时 750 毫秒
1.
The present study investigated the decrement in nutrient-based conditioned flavor preference found in hungry rats exposed
to a flavor following simultaneous flavor–sucrose conditioning while thirsty. Although a significant decrease in preference
was found in the experimental group in each experiment, there was no evidence of either spontaneous recovery (Experiment 1) or reinstatement (Experiment 2). In addition, posttraining flavor exposure weakened the original flavor–sucrose association (Experiment 3). These results suggested that the flavor–US association might have been impaired after posttraining flavor exposure. Two
further experiments assessed whether the flavor acquired the properties of a net inhibitor, using the retardation and summation
tests for conditioned inhibition. Experiment 4 revealed that the flavor suffered retardation when retraining was conducted after the exposure phase. In Experiment 5, the target flavor decreased the preference shown for a different flavor previously paired simultaneously with sucrose when
both were presented forming an unreinforced compound in the summation tests. None of these effects was found in a control
group, which had received serial flavor → nutrient presentations during training. Together, these results suggest that a flavor
simultaneously paired with sucrose acquires the properties of a net inhibitor when it is subsequently presented outside the
compound to hungry animals. 相似文献
2.
Two experiments were conducted to investigate functional similarities between “hunger CRs” of Konorski’s (1967) model of appetitive classical conditioning and sign-tracking behavior in rats. Konorski’s model predicts that hunger CRs will be facilitated (1) when a nonrein-forced stimulus similar to the reinforced CS is introduced, and (2) when some CS presentations are unexpectedly nonreinforced. In Experiment 1, hungry rats acquired a leverpress response to a retractable lever that was paired with response-independent food. Following this training, a second lever was introduced whose presentation was not followed by food. The effect of the presence of this second lever was to facilitate responding to the original lever. In Experiment 2, single-lever autoshaping training was followed by a shift from 100% pairing of the lever with food to only 50% of the lever presentations being followed by food. The introduction of partial reinforcement produced an immediate and durable increase in leverpressing. The findings of both experiments are consistent with predictions from Konorski’s model of classical conditioning if sign-tracking is considered as a “hunger CR.” 相似文献
3.
In the first four experiments, it was found that aversions to saccharin solution produced by contingent poisoning were similar regardless of whether the rats had been trained under the test deprivation or under a different deprivation; the two deprivation states used were thirst and satiety. In Experiment 5, rats were poisoned after drinking grape juice while hungry or poisoned after drinking milk while thirsty, but they were not poisoned after grape-thirst or milk-hunger combinations. In abstract terms, poisoning occurred after AX and BY stimulus combinations, but did not occur after AY and BX combinations. There was some learning under these discrimination conditions. 相似文献
4.
Robert A. Rescorla 《Learning & behavior》1990,18(2):206-211
In three experiments, thirsty rats were trained to make several instrumental responses whose outcomes differed in which of two relatively inconsequential flavor features they contained. In Experiment 1, one of the features was subsequently devalued by pairing it with lithium chloride; in Experiment 2, it was enhanced in value by pairing it with sucrose. In both experiments, differences in the value of the features resulted in parallel differences in the likelihood of the responses during a subsequent extinction test. In Experiment 3, the animals chose between these responses in the presence of discriminative stimuli that had signaled the occurrence of these different features following another response. The stimuli selectively augmented the likelihood of the response with which they shared training by the same-flavored consequence. These results indicate that rats can separately encode features that differ along one dimension, both in the association between an instrumental response and its outcome, and in the association between a discriminative stimulus and that outcome. 相似文献
5.
In Experiment I, rats received one food rewarded trial per day in a runway. One group received all its trials under hunger (Group H); the second group received a random half of its trials under hunger and the other half of its trials under hunger plus thirst (Group H-HT). Group H-HT ultimately ran slower on HT trials than on H trials. In Experiment II, the effects of shifting from H to HT and vice versa were examined in a five-phase design. In general, rats run under H ran faster than rats run under HT, and shifts from H to HT produced rapid decreases in speed, while shifts from HT to H produced extremely slow increases in speed. The results of both experiments were interpreted as indicating that the reward value of food is greater under H than under HT and that the manipulation H vs. HT may be viewed as theoretically similar to manipulation of reward magnitude. 相似文献
6.
Three experiments, using rats, demonstrated the encoding of a food unconditioned stimulus (US) in a simple Pavlovian conditioning paradigm. In all three studies, one stimulus was used to signal the delivery of pellets and a different stimulus was used to signal the delivery of sucrose. In Experiment 1, postconditioning devaluation of one of the food USs selectively reduced the frequency of conditioned magazine-directed behavior during the stimulus trained with that US. In Experiment 2, transfer of the stimuli to instrumental responses resulted in selective depression of the response trained with a different outcome. In Experiment 3, acquisition of stimulus-outcome learning was impaired by unsignaled intertrial presentations of the same outcome but not of a different outcome. These results indicate that a detailed representation of the outcome is encoded in the normal course of Pavlovian conditioning. 相似文献
7.
John H. Hull 《Learning & behavior》1977,5(2):207-212
Experiments 1, 2, and 3 showed that food-deprived rats responding for food pellets made significantly more long-duration leverpresses than water-deprived rats responding for water drops. These experiments further showed that this difference in instrumental response topography is long-lived, and depends neither upon idiosyncrasies of the experimental chamber nor upon severity of deprivation conditions. In Experiment 4, food-deprived rats responding for food pellets made significantly more long-duration leverpresses than did either food- or water-deprived rats responding for sucrose solution. Human judges in Experiment 5 were able to correctly identify instrumental leverpress responses by rats as being for food or water based solely on previous viewings of other rats drinking water or eating food pellets. It appears that instrumental response topographies in rats vary depending principally upon the reinforcer received, and that these instrumental response topographies resemble consummatory response topographies. 相似文献
8.
The control of goal-directed, instrumental actions by primary motivational states, such as hunger and thirst, is mediated by two processes. The first is engaged by the Pavlovian association between contextual or discriminative stimuli and the outcome or reinforcer presented during instrumental training. Such stimuli exert a motivational influence on instrumental performance that depends upon the relevance of the associated outcome to the current motivational state of the agent. Moreover, the motivational effects of these stimuli operate in the absence of prior experience with the outcome under the relevant motivational state. The second, instrumental, process is mediated by knowledge of the contingency between the action and its outcome and controls the value assigned to this outcome. In contrast to the Pavlovian process, motivational states do not influence the instrumental process directly; rather, the agent has to learn about the value of an outcome in a given motivational state by exposure to it while in that state. This incentive learning is similar in certain respects to the acquisition of “cathexes” envisaged by Tolman (1949a, 1949b). 相似文献
9.
Ruth M. Colwill 《Learning & behavior》2001,29(2):153-164
The effect of noncontingent outcomes on an instrumental response-outcome (R-O) association was examined in four experiments using transfer tests. In each experiment, rats were first given instrumental discrimination training designed to establish different stimuli as signals (S+s) for different outcomes. Transfer responses were subjected to different treatments across the experiments and then tested with the S+s. In Experiments 1 and 2, two transfer responses were both initially trained with two contingent outcomes. Then, each transfer response was subjected either to the addition of noncontingent presentations of one of those outcomes (Experiment 1) or to the replacement of one of the contingent outcomes with noncontingent presentations of that outcome (Experiment 2). Transfer tests revealed no significant difference in the ability of an S+ to promote performance of a transfer response based on their shared association with either the contingent or the noncontingent outcome. These results suggest that a response reinforced with two outcomes remains equally well associated with both of those outcomes despite prolonged exposure to noncontingent presentations of one of those outcomes. In Experiments 3 and 4, the possibility that the noncontingent schedules of reinforcement used in Experiments 1 and 2 might be capable of establishing an association between a response and its noncontingent outcome was examined. Transfer responses were trained with one contingent outcome and a different noncontingent outcome. Performance of these transfer responses was augmented more by presentations of an S+ trained with the contingent outcome than with the noncontingent outcome. These results confirm previous reports that instrumental responses are sensitive to outcome contingencies in acquisition and that noncontingent outcome presentations do not weaken previously established R-O associations. Several explanations are considered for the failure of subsequent noncontingent presentations of an outcome to reduce the strength of its association with the instrumental response. 相似文献
10.
The role of incentive learning in instrumental performance following an upshift in the degree of water deprivation was analyzed in three experiments. In Experiments 1A and 1B, rats trained to perform an instrumental action reinforced by either sucrose or maltodextrin solutions when in a low-deprivation state were shifted to a high-deprivation state and tested in extinction. This shift in water deprivation increased performance only if the animals had been exposed to the reinforcer in the high-deprivation state prior to testing. In Experiment 2, the role of the instrumental contingency in mediating the preexposure effect observed in the first two studies was examined by training rats to make two instrumental actions for different outcomes. The preexposure experience with the outcomes produced a relative increase in performance of the action reinforced with the incentive preexposed in the high-deprivation state when a choice between the two response alternatives was conducted in that state. These experiments support the conclusion that instrumental performance following revaluation of the reinforcer by an upshift in the level of thirst depends on a process of incentive learning. 相似文献
11.
William P. Bellingham Katy Gillette-Bellingham E. James Kehoe 《Learning & behavior》1985,13(2):152-164
Discrimination between a tone + light compound and its components in positive and negative patterning schedules was examined. In the positive schedule, reinforced compound presentations (C+) were intermixed with unreinforced component presentations (T?, L?). In the negative schedule, the compound was unreinforced (C?) and the components were reinforced (T+, L+). In Experiment 1, appetitive conditioning of rats’ anticipatory magazine responses was used, and in Experiment 2, aversive conditioning of the rabbit’s nictitating membrane response was used. Both experiments revealed that the positive patterning schedule consistently produced rapid acquisition of appropriate discriminative responding. The results of the negative patterning schedule were more complex. Specifically, the results of Experiment 1 demonstrated that naive rats initially showed rapid acquisition of the negative patterning discrimination. However, schedule reversals revealed that experience with the positive patterning schedule virtually abolished subsequent acquisition of discriminative responding under the negative patterning schedule. The results of Experiment 2 revealed that naive rabbits showed very slow acquisition of discriminative responding under the negative patterning schedule. The results are discussed in relation to the unique-stimulus hypothesis, a contextual encoding hypothesis, and a configural hypothesis. 相似文献
12.
Elizabeth D. Capaldi David E. Myers David H. Campbell Joan Denise Sheffer 《Learning & behavior》1983,11(1):107-115
In five experiments, rats’ preference for a flavor was greater if the flavor had previously been consumed under low rather than high deprivation. This preference was conditioned in as few as three flavor-deprivation pairings (Experiment 1), and persisted through 28 test days, half under each deprivation level (Experiment 2). Rats never preferred the flavor associated with high deprivation even when calories were increased by giving 40 ml of 8% sucrose or when caloric density was increased to the equivalent of 20% sucrose. The preference for the low-deprivation flavor was greater when saccharin solutions were used rather than sucrose solutions, but the preference did emerge when sucrose solutions were used as testing proceeded and when a lower concentration of sucrose was used. We suggest that these preferences may be a result of flavor-taste associations rather than associations between flavors and postingestive consequences, and that the taste of the solutions under low deprivation is preferred to the taste under high deprivation. 相似文献
13.
Delamater AR 《Learning & behavior》2011,39(3):259-270
Two experiments with thirsty rats explored the harmful effects of non-reinforced exposures to a flavor cue in the control
by sensory-specific flavor–sucrose associations in a conditioned flavor preference paradigm. Experiment 1 demonstrated that rats learned to prefer a flavor cue that was consistently paired with sucrose over one that was paired
with sucrose the same number of times but was also presented without sucrose on other occasions. However, rats for which sucrose
was devalued following the conditioning phase preferred the partially reinforced flavor cue over the consistently reinforced
flavor, suggesting that non-reinforcement weakened the ability of that flavor cue to evoke a specific representation of sucrose
during the preference test. Experiment 2 demonstrated comparable effects of non-reinforcement in a latent inhibition procedure, although relatively more non-reinforced
pre exposures to the flavor, in conjunction with fewer flavor–sucrose pairings, were required to see the effect. Together,
the results suggest, as is often found with more traditional learning paradigms, that non-reinforcement of a flavor cue has
deleterious effects on preference learning and/or performance. 相似文献
14.
In Experiment I, rats which were both hungry and thirsty were given a choice between a food reward and a water reward. The animals preferred food to water when the reward was delivered immediately, but preferred water to food when a 30-sec delay was imposed in the goalbox before the reward was received. Experiment II replicated the results of the first experiment and showed, in addition, that when the delay was imposed in a separate delay chamber devoid of differential goalbox cues, subjects preferred food to water, similar to the immediate group. The results were discussed in terms of an incentive value process and a competing response hypothesis. 相似文献
15.
Two experiments examined the counterconditioning of an aversively motivated response in rats. Presentation of a highly palatable sugar solution (maltose in Experiment 1; sucrose in Experiment 2) to thirsty rats was used as the counterconditioning treatment. In Experiment 1, the counterconditioning procedure was found to be effective in modifying both a newly acquired and a cue-reactivated fear memory. In Experiment 2, the counterconditioning effect was shown to occur when the fear memory was reactivated with a noncontingent exposure to the unconditioned stimulus rather than the conditioned stimulus. This outcome supports the interpretation of counterconditioning as a modification of some central representation of the original training memory, rather than the acquisition of a competing peripheral response. The methodological implications of the present approach to counterconditioning are considered. 相似文献
16.
Four experiments examined the effects of separate presentations of shock on conditioned suppression of instrumental responding evoked by a CS previously paired with shock. Experiment 1 showed that conditioned suppression of responding resulting from noise-shock pairings increased as a function of time after the initial noise-shock pairings. However, it also showed that this time-dependent increase in conditioned suppression of responding could be attenuated by presentations of light-shock pairings immediately prior to the test of the noise CS. Experiment 2 showed that this attenuation effect can be produced by presentations of either light-shock pairings or shock alone. Experiment 3 showed that the magnitude of this attenuation effect was directly related to the temporal proximity of the light-shock pairings to the test of the noise CS. Experiment 4 showed that the magnitude of this attenuation effect was inversely related to the intensity of separate shock presentations. 相似文献
17.
Fast, “playful” running was obtained in rats never given reward for running in an alley. The maintenance of such running was not dependent on hunger, thirst, or an “exercise” drive produced by confinement in small home cages. However, hunger facilitated the development of “playful” nonrewarded running in rats which initially did not run when food-satiated. “Playful” running was not seen in hungry, rewarded rats or in hungry, nonrewarded rats fed immediately after their daily running sessions. Probably incentive, but not drive, prevents the occurrence of self-reinforcing running. 相似文献
18.
Ruth M. Colwill 《Learning & behavior》1991,19(4):326-336
Three experiments using rats examined whether a signal for the nonreinforcement of an instrumental response (S-) provided information about the identity of the omitted outcome. In all three experiments, one stimulus was established as a signal for the nonreinforcement of a response that earned food pellets and another stimulus signaled the nonreinforcement of a response that earned liquid sucrose. Experiment 1 found that each S-suppressed another instrumental response trained with the same outcome significantly more than a response trained with a different outcome. Using a variant of this transfer design, Experiment 2 demonstrated that an S- was slower to develop discriminative control over a new response reinforced in its presence with the same outcome compared with an outcome different from the one whose omission-the S- had previously signaled. Experiment 3 examined transfer of the S- stimuli to a response trained with two outcomes, one of which had subsequently been devalued. Performance of this response significantly increased in the presence of a signal for the omission of the devalued outcome, but decreased in the presence of a signal for the omission of the valued outcome. These results suggest that S-s do provide information about the identity of omitted response-contingent outcomes. 相似文献
19.
Four experiments were conducted to explore outcome-specific transfer from causal predictive judgments to instrumental responding. A video game was designed in which participants had to defend Andalusia from navy and air force attacks. First, they learned the relationship between two instrumental responses (two keys on a standard keyboard) and two different outcomes (destruction of the ships or destruction of the planes). Then they learned to predict which of two different stimuli predicted which outcome. Finally, they had the opportunity of making either of the two instrumental responses in the presence of either stimulus. Transfer was shown as a preference for the response that shared an outcome with the current stimulus. The presentation of the stimulus during the test produced a decrease in the overall rate of response. Responding to a neutral stimulus in Experiments 2 and 3 suggested that this overall decrease in responding was due to a combination of the time needed to process the meaning of the stimulus and the activation of the representation of the outcome in the presence of the stimulus during the test. Transfer between predictive judgments and instrumental responding mirrors the outcome-specific Pavlovian instrumental transfer observed in conditioning studies with rats. 相似文献
20.
The source of renewal of instrumental responding in rats was investigated. In Experiment 1, two responses (R1 and R2) were reinforced with one outcome (O1) in contexts A and B (i.e., R1→O1, R2→O1), and then R2 was extinguished in A and R1 was extinguished in B. At test, the rate of R1 was higher than that of R2 in context A, and the reverse was the case in context B: Renewed responding was independent of the Pavlovian context→O1 associations. In Experiment 2, all rats received R1→O1 and R2→O2 trials in A and then were placed in B, where they were sated on O2 and either did (Group Extinction) or did not (Group No Extinction) receive concurrent extinction of R1 and R2. At test, we found more responding in A than in B for Group Extinction, but not for Group No Extinction, and the renewed responding in A was as sensitive to the current value of the outcome as responding that had not been subject to extinction (i.e., the rate was higher for R1 than for R2). That is, the renewed responding was goal-directed. These results identify the removal of contextual inhibion of either the response or the response→outcome associaon as potenal bases for renewal, and the response→outcome associaon as the source of renewed responding. 相似文献