共查询到20条相似文献，搜索用时 62 毫秒
1.
Eric W. Holman 《Learning & behavior》1976,4(3):329-332
In Experiment I, rats received eight habituation injections of either lithium chloride (LiCl) or sodium chloride (NaCl), then two aversion training trials in which access to saccharin solution was followed by LiCl injections, and finally eight extinction trials with saccharin but no injections. The rats habituated to LiCl showed less aversion to saccharin during training and extinction. In Experiment II, rats received two aversion training trials, then eight habituation trials to either LiCl or NaCl, then eight extinction trials, four more aversion training trials, and eight more extinction trials. The rats habituated to LiCl did not differ during the first extinction period from those habituated to NaCl, but showed less aversion to saccharin during the second training and extinction periods. Consequently, habituation to LiCl reduces the learning of an aversion to saccharin but does not reduce the performance of a previously learned aversion. 相似文献
2.
In four experiments utilizing an appetitive conditioning preparation, reacquisition of conditioned responding was found to occur both rapidly and slowly following extinction. In Experiment 1, acquisition of responding to a tone that had been conditioned and extinguished occurred more rapidly than acquisition in either a group that received equivalent exposure to the food unconditioned stimulus or a “rest” control group that received only exposure to the apparatus in the first two phases. However, reacquisition was impaired relative to acquisition in a “learning-experienced” group that had previously received conditioning and extinction with a different stimulus. Experiments 2 and 3 produced similar results, but also found that high responding during reacquisition was confined to trials that followed reinforced, rather than nonreinforced, trials. Experiment 4, in which very few initial conditioning trials were used, produced reacquisition that was slow compared with both learning-experienced and rest controls. The results are consistent with a role for sequential learning: Reacquisition is rapid when animals have learned that reinforced trials signal other reinforced trials. 相似文献
3.
Water-deprived rats were given a single exposure to saccharin and LiCl, either paired or unpaired. Half the subjects then received three saccharin-only exposures (extinction) in the training enclosure, followed by a single LiCl-only presentation (unconditioned stimulus reinstatement) 8 days after conditioning. The remaining subjects received six saccharin-only exposures, followed by LiCl reinstatement 13 days after conditioning. In both cases LiCl reinstatement occurred outside the training/test context. Appreciable recovery from extinction was observed after the partial loss of taste aversion obtained with three extinction sessions and the 8-day conditioning-reinstatement interval, but not after the asymptotic loss of taste aversion obtained with six extinction sessions and the 13-day conditioning-reinstatement interval. Conditioned taste aversions appear to be similar to more traditional associations with respect to both extinction and reinstatement-induced recovery from extinction. The results are discussed with reference to the event-memory, contextual-conditioning, and facilitated-retrieval hypotheses of postextinction reinstatement effects. 相似文献
4.
In two experiments, saccharin (CS) and lithium chloride (US) were paired in a context consisting of specific visual, auditory, tactual, and olfactory cues. The saccharin aversion was then extinguished in a context free from conditioning-context cues. Later, saccharin preference tests were given in the presence and absence of these cues. The results indicated that the background cues of the conditioning trial controlled the amount of saccharin drunk on extinction trials, and, furthermore, that extinction of the taste aversion was context specific; i.e., groups given extinction trials in a different (from conditioning) context retained their saccharin aversion in the conditioning context only. The results indicate an important role played by the exteroceptive context in taste-aversion conditioning. 相似文献
5.
Experiment 1 investigated the effects of US habituation on the acquisition and extinction of learned taste aversions in rats. Subjects receiving five noncontingent LiCl intubations prior to conditioning failed to develop a conditioned taste aversion, while control subjects experiencing a single saccharin/LiCl pairing displayed a pronounced taste aversion which weakened during subsequent poisonings. Experiment 2 examined whether habituation, defined as a waning of responses to repeated presentation of an illness stimulus, was a possible mechanism for explaining the results of Experiment 1. Subjects showed a decrease in motor activity following an initial LiCl intubation, but less attenuation of activity with successive intubations. 相似文献
6.
Extinction of a conditioned palatability shift preceded extinction of conditioned taste avoidance whether rats were tested
using a within-subjects design or a between-subjects design. In each of two experiments, consumption of 0.1% saccharin was
paired with either 20 ml/kg of 0.15 M LiCl or equivolume physiological saline on a single trial. In Experiment 1, on each
of 10 extinction trials, rats were given a taste reactivity test immediately prior to a consumption test. In Experiment 2,
half of the rats were extinguished by taste reactivity testing and half of the rats were extinguished by a consumption test
on each of 10 extinction trials. In both experiments, the aversive reactions of gaping and passive dripping were extinguished
in a single trial and the suppression of ingestive reactions was extinguished in 2 trials; however, extinction of taste avoidance
required 4–5 trials. These results suggest that rats continue to avoid a lithium-paired flavor even when they do not have
an aversion to the taste. 相似文献
7.
Rick A. Bevins Heather C. Jensen Todd S. Hinze Joyce Besheer 《Learning & behavior》1999,27(3):358-366
Rats (Rattus norvegicus) that received a taste cue (saccharin, saline, quinine, or sucrose) paired with a lithium chloride (LiCl) injection displayed
a robust decrease in consumption of that taste, relative to controls that had the taste unpaired with LiCl. Consumption of
the paired taste increased with each nonreinforced presentation (i.e., extinction). After asymptotic extinction, rats that
had had a 0.1% saccharin cue paired with LiCl consumed less of the saccharin solution than did controls. A similar data pattern
was observed with a 10% sucrose solution. These results are consistent with the view that some aspect of the excitatory CS-US
association remains after extinction. On the other hand, rats that had a bitter (0.005% or 0.001% quinine) or salty (1% or
0.5% saline) solution paired with LiCl drank similar amounts of the fluid as controls after asymptotic extinction treatment.
Together, these experiments suggest that a taste that is either sweet or preferred is required in order to demonstrate the
chronic decrease in fluid consumption after extinction treatment. The data suggest that the conditioning experience prevents
the later development of a preference for the sweet taste, rather than there being a retained aversion that suppresses fluid
consumption. 相似文献
8.
In the present experiments, savings phenomena following a limited amount of initial acquisition and extended extinction were
examined. Experiments 1 and 2 compared rates of reacquisition following brief acquisition and various amounts of extinction
in conditioning of the rabbit’s nictitating membrane and heart rate response, respectively. Experiment 3 compared rates of
acquisition to a novel stimulus (e.g., light) following brief acquisition and various amounts of extinction to another stimulus
(e.g., tone). In addition, in Experiment 3 recovery of responding to the extinguished stimulus during acquisition to the novel,
cross-modal stimulus was examined. Experiments 1, 2, and 3 demonstrated that with a limited number of acquisition trials (1)
there was a graded reduction in the rate of reacquisition as a function of the number of extinction trials in both conditioning
preparations, (2) there was a graded reduction in the rate of cross-modal acquisition as a function of the number of extinction
trials, but (3), in Experiment 3, recovery of responding to the extinguished stimulus during cross-modal training of the novel
stimulus appeared uniformly robust even in the face of extended extinction. 相似文献
9.
In five conditioned taste aversion experiments with rats, summation, retardation, and preference tests were used to assess the effects of extinguishing a conditioned saccharin aversion for three or nine trials. In Experiment 1, a summation test showed that saccharin aversion extinguished over nine trials reduced the aversion to a merely conditioned flavor (vinegar), whereas three saccharin extinction trials did not subsequently influence the vinegar aversion. Experiment 2 clarified that result, with unpaired controls equated on flavor exposure prior to testing; the results with those controls suggested that the flavor extinguished for nine trials produced generalization decrement during testing. In Experiment 3, the saccharin aversion reconditioned slowly after nine extinction trials, but not after three. Those results suggested the development of latent inhibition after more than three extinction trials. Preference tests comparing saccharin consumption with a concurrently available fluid (water in Experiment 4, saline in Experiment 5) showed that the preference for saccharin was greater after nine extinction trials than after three. However, saccharin preference after nine extinction trials was not greater, as compared with that for either latent inhibition controls (Experiments 4 and 5) or a control given equated exposures to saccharin and trained to drink saline at a high rate prior to testing (Experiment 5). Concerns about whether conditioned inhibition has been demonstrated in any flavor aversion procedure are discussed. Our findings help explain both successes and failures in demonstrating postextinction conditioned response recovery effects reported in the conditioned taste aversion literature, and they can be explained using a memory interference account. 相似文献
10.
In four experiments using rat subjects, we investigated the effects of presenting a novel flavor cue at the time of pairing an environmental context with illness. In each experiment, the subjects were allowed to spend time in a distinctive cage before receiving an injection of LiCl. For some, plain water was made available on these conditioning trials; for others, a novel taste (HCl) was presented. We measured the strength of the context aversion by assessing the ability of the contextual cues to block the acquisition of an aversion to sucrose in a further phase of training. We found that initial training with HCl present made the context less effective as a blocking cue and concluded that the HCl had overshadowed learning about the context. We suggest that this blocking procedure provides a more accurate assessment of contextual aversion than does the consumption test that has more usually been used and that taste-context overshadowing may be a more robust phenomenon than has thus far been thought. 相似文献
11.
Todd R. Schachtman Wesley J. Kasprow Robert C. Meyer Mark J. Bourne Julie A. Hart 《Learning & behavior》1992,20(3):207-218
Using a conditioned taste aversion preparation overshadowing of flavor-illness association was produced through the presentation of a second flavor during the interval between the first flavor and illness. The modulatory effects of extinguishing the association between the second (over-shadowing) flavor and illness on conditioned responding to the target flavor was investigated. In Experiment 1, we found that, following one-trial overshadowing, extinction of the overshadowing flavor had no effect on conditioned responding to the target flavor. In Experiment 2, we found a similar absence of an effect of extinction of the overshadowing stimulus in a multitrial over-shadowing paradigm. Experiment 3 confirmed the results of Experiments 1 and 2 using conditioning parameters that were designed to weaken the association between the overshadowed flavor and illness. In Experiments 4 and 5, we used simultaneous presentation of the flavors during conditioning and obtained a weakened aversion to the overshadowed flavor when the overshadowing CS was extinguished. These findings are inconsistent with previous observations in conditioned fear preparations that suggest that extinction of the association between the overshadowing stimulus and the unconditioned stimulus attenuates overshadowing. Possible reasons for the discrepant results are discussed. 相似文献
12.
Second-order conditioning of social approach to a female conspecific in male Japanese quail was investigated in four experiments. Subjects that received paired first- and second-order trials acquired second-order conditioning in both Experiments 1 and 2. In contrast, subjects that received paired first-order but unpaired second-order trials, and subjects that received unpaired first-order but paired second-order trials, did not acquire second-order conditioning. In Experiment 3, subjects for whom the first-order conditioned stimulus was presented in extinction showed second-order conditioning comparable to that shown by subjects in a control group that did not receive the extinction procedure. In Experiment 4, subjects approached a second-order stimulus less when sexually satiated than when sexually deprived. These findings suggest that second-order sexual conditioning in quail is mediated by an association of the second-order stimulus with a representation of the unconditioned stimulus. 相似文献
13.
Weanling rats were tested for retention of an aversion to a novel flavor (chocolate milk) that had been conditioned as a single-element conditioned stimulus (CS) or in compound with a novel ambient odor (banana). The presence of the ambient odor during conditioning had no effect on flavor aversion shortly thereafter, confirming previous results. The flavor aversion observed 21 days after conditioning, however, was significantly stronger for pups conditioned with the single-element CS than for those given the flavor-odor compound as the CS. This retention effect was due to a surprisingincrease in the conditioned aversion observed 21 days after conditioning with the single-element CS. A second experiment confirmed this paradoxical increase in retention of the aversion to chocolate milk. This experiment also verified that no such increase occurred in retention of the conditioned aversion to a different flavor (saccharin), whether the initial aversion was strong or weak. The results may be explained in terms of generalized latent inhibition from consumption of mother’s milk. 相似文献
14.
Richard V. Krane 《Learning & behavior》1980,8(4):513-523
The types of conditioned properties acquired by novel (i.e., nonpreexposed) or familiar (i.e., preexposed) exteroceptive cues that were paired with toxicosis, in the absence of a flavor CS, were evaluated in four experiments. In Experiment 1, the conditioned properties of novel exteroceptive cues served to block the acquisition of an aversion to a flavor CS during flavor conditioning and to suppress the ingestion response during flavor testing; animals failed to suppress their ingestion of either the flavor CS or a neutral flavor when tested in the absence of the exteroceptive CS, but suppressed their ingestion of both the flavor CS and the neutral flavor when tested in the presence of the exteroceptive CS. In Experiment 2, preexposed exteroceptive cues that had been paired with toxicosis failed to provide evidence of such conditioned properties. Experiment 3 demonstrated that preexposed contextual cues that were reinforced in compound with novel exteroceptive cues failed to acquire the conditioned properties acquired by nonpreexposed contextual cues under the same conditions of reinforcement. Finally, in Experiment 4, the conditioned properties of the novel exteroceptive cues served to evoke a conditioned gastrointestinal response that gradually extinguished as a function of repeated nonreinforced exposures to the exteroceptive cues, and, in the absence of such extinction, the conditioned properties served to block the acquisition of a flavor aversion. 相似文献
15.
In three experiments, we set out to determine whether the response of rats to an injection of LiCl would be modified by the presence of an environmental context that had previously been paired with LiCl. Experiment 1 confirmed that one feature of the malaise produced by LiCl is a reduced tendency to consume an otherwise palatable flavor. Experiment 2 showed that the size of this response was enhanced if it was measured in the presence of a conditioned context. In Experiment 3, we investigated the possibility that the postinjection response could be modified by an overshadowing treatment given during the conditioning phase. The significance of these findings for the understanding of chemotherapyinduced nausea in the clinical population is discussed. 相似文献
16.
Adult rats were injected with lithium chloride (LiCl) after consumption of a novel flavor (chocolate milk) that either was or was not presented together with a novel ambient odor (banana) as a compound conditioned stimulus (CS). In Experiment 1, the adults’ consumption of the flavor 24 h after conditioning was compared with that of weanling rats given the same conditioning treatment on Postnatal Day 21. The results confirmed previous indications that the reduction in aversion observed for adults conditioned with the compound CS (overshadowing) was weak or nonexistent in weanlings. After a longer retention interval (21 days), there was no evidence of overshadowing in adults despite maintained retention of the basic conditioned aversion. In Experiment 2 this decrease in overshadowing after a long retention interval was replicated with adult animals and extended to a different method of testing. The form of the effect was the same as in Experiment 1: The decrease in overshadowing occurred over the retention interval without loss in retention of the basic taste aversion; the decrease in overshadowing was a consequence of anincrease in the flavor aversion displayed by animals conditioned with the compound CS. The impaired flavor aversion (i.e., the overshadowing) observed shortly after conditioning apparently was due to factors associated with memory retrieval, rather than to reduced attentional or associative strength. 相似文献
17.
Rats tend to prefer flavors previously consumed under low deprivation to flavors previously consumed under high deprivation (Capaldi & Myers, 1982). We attempted to distinguish among possible associative explanations by determining whether this conditioning phenomenon was based upon conditioned preferences, conditioned aversions, or both. We compared preference for flavors presented exclusively under either high or low deprivation with preference for a neutral flavor. In Experiments 1A and 1B the neutral flavor was one that had been randomly paired with both high and low deprivation, whereas in Experiments 2 and 3 the neutral flavors had not been associated with either high or low deprivation. Our results strongly suggest that this conditioning phenomenon is based upon an actual increase in preference for the flavor consumed under low deprivation rather than on any form of aversion conditioning. 相似文献
18.
The attenuation of an LiCl-induced conditioned taste aversion (CTA) by LiCl preexposure is mediated primarily by associative blocking via injection-related cues. Given that preexposure to morphine attenuates morphine-induced CTAs, it was of interest to determine whether injection cues also mediate this effect. Certain morphine-induced behaviors such as analgesic tolerance are controlled associatively, via injection-related cues. Accordingly, animals in the present experiments were preexposed to morphine (or vehicle) every other day for five total exposures, followed by an extinction phase, in which the subjects were given saline injections (or no treatment) for 8 (Experiment 1) or 16 (Experiment 2) consecutive days. All of the animals then received five CTA trials with morphine (or vehicle). The morphine-preexposed animals in Experiment 1 displayed an attenuation of the morphine CTA that was unaffected by extinction saline injections, suggesting that blocking by injection cues during morphine preexposure does not mediate this effect. All of the morphine-preexposed subjects in Experiment 2 displayed a weakened preexposure effect, an effect inconsistent with a selective extinction of drug-associated stimuli. The attenuating effects of morphine preexposure in aversion learning are most likely controlled by nonassociative mechanisms, like drug tolerance. 相似文献
19.
Goldfish trained to discriminate between signals paired with shock (S?) and signals paired with shock omission (S+) with a linear presentation procedure, originally learned (OL) to control the signal state of a shuttle box and showed a decided preference for the S+ signal. In Experiment 1, following OL, groups had one OL signal replaced (S+ or S?), both signals replaced (S+ and S?), or the OL signals reversed (S+ and S? reversed) and were then tested in a transfer training procedure. In transfer, groups with one signal replaced maintained discriminated performance at OL levels; the S+ replaced group was slightly superior to the S? replaced group on the first day of transfer. With both OL signals replaced, discrimination dropped to chance performance levels, whereas, with OL signal shock pairing reversed, discrimination performance dropped below chance levels. In Experiment 2, following OL, extinction procedures consisted of turning off the shocker (0% shock) or of shocking 100% or a random 25% of the trials. A fourth extinction procedure (R,) retained the trial start response-dependent shock-omission contingency, but shock differentiating the S+ and S? signals was eliminated entirely. Extinction of the S+/S? discrimination was measured both during extinction training per se and with reversal retraining of the S+/S? discrimination later. Groups for which the OL S+ was paired with shock during extinction extinguished on both measures, but groups for which the OL S? was paired with shock omission did not extinguish, especially as shown by the reversal test procedure. Theoretical implications and the implications for several conditioning procedures are discussed. 相似文献
20.
In Experiments 1 and 2, rats were exposed to two compound flavors, AX and BX, containing one flavor in common (X). Following this exposure phase, an aversion was conditioned to A in the experimental group by pairing its consumption with an injection of lithium, while a control group drank A without being poisoned. The effect of this treatment was to establish B as a conditioned inhibitor. In Experiment 1, experimental animals were slower than controls to condition an aversion to B when its consumption was paired with lithium (a retardation test of conditioned inhibition). In Experiment 2, B alleviated the suppression of intake of another flavor previously paired with lithium (a summation test). Experiments 3 and 4 established that these effects depended upon prolonged prior exposure to AX and BX. 相似文献