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1.
In a series of related experiments, we studied associative phenomena in snails (Helix aspersa), using the conditioning procedure of tentacle lowering. Experiments 1A and 1B demonstrated a basic conditioning effect in
which the pairing of an odor (apple) as the conditioned stimulus (CS) with the opportunity to feed on carrot as the unconditioned
stimulus (US) made snails exhibit increased levels of tentacle lowering in the presence of the CS. Experiments 2 and 3 showed
that the magnitude of the conditioning was reduced when snails were exposed to the CS prior to the conditioning trial (a latent
inhibition effect). Experiment 4 examined the effects produced by pairing a compound CS (apple—pear) with food presentations
and demonstrated the existence of an overshadowing effect between the two odors. Experiment 5 revealed that pairing one CS
with another previously conditioned stimulus increased tentacle lowering to the new CS (a second-order conditioning effect).
Finally, Experiment 6 showed that pairing two odors prior to conditioning of one of them promoted an increase in tentacle
lowering in response to the other (a sensory preconditioning effect). The results are discussed in terms of an associative
analysis of conditioning and its implications for the study of cognition in invertebrates. 相似文献
2.
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
3.
Aversive chemosensory conditioning altersHermissenda’s feeding behavior. But opposite behavioral changes have been reported, depending on whether discrete-trial or context-conditioning
paradigms were used, raising questions about the roles of associative and nonassociative processes. We attempted to produce
chemosensory contextual conditioning but failed to do so across a wide range of conditions. In Experiments 1–3, we observed
large, nonspecific bite latency increases to shellfish extracts, regardless of whether they had signaled the presence or absence
of shaking. In Experiment 4, we found that mere exposure to shellfish extract produced latency increases; vestibular stimulation
was unnecessary. In a final experiment, using Y-maze choice tests, we failed to observe selective reductions in animals’ preference
for shellfish paired with shaking. Nonassociative processes stemming from prolonged exposure to concentrated shellfish extracts
appear to be major factors in our failure to demonstrate associative chemosensory contextual conditioning. 相似文献
4.
M. A. Ungless 《Learning & behavior》1998,26(1):15-19
Following brief pairing of an odor with a feeding experience (food-attraction conditioning), snails will lower their tentacles when subsequently presented with that odor alone. Three experiments investigated the possible behavioral mechanism mediating food-attraction conditioning in the snailHelix aspersa. It is suggested that food-attraction conditioning is an example of Pavlovian conditioning. In this case, the odor (conditioned stimulus) is paired with oral stimulation (unconditioned stimulus), which elicits lowering of the tentacles (unconditioned response). Following conditioning, the odor comes to elicit lowering of the tentacles (conditioned response). Experiment 1 ruled out nonassociative effects, such as habituation and sensitization, using an unpaired control group. Experiment 2 provided further evidence against a role for habituation of neophobia, through the demonstration of extinction following conditioning. In Experiment 3, an omission procedure was used to rule out the possible role of instrumental contingencies. 相似文献
5.
In two experiments, the influence of exposure to a CS? on the acquisition and retention of a conditioned odor aversion was examined. Preweanling rats were given exposure to the CS? either prior to (CS?/CS+) or following (CS + /CS?) the pairing of a second odor (the CS+) with footshock. The results of Experiment 1 indicated that subjects in both of the treatment conditions acquired aversions of comparable strength to the odor paired with footshock and that retention of the odor aversion was not affected by order of stimulus presentation during conditioning. Experiment 2 indicated, however, that the effectiveness of pretest exposure to various elements of the conditioning episode in reactivation of the memory for conditioningwas dependent on the order of stimulus presentation during conditioning. This differential effectiveness of the various reactivation treatments is discussed in terms of their relationship to the associative “status” of the stimuli present during conditioning and in terms of the information provided to the animal by the reactivation treatment. 相似文献
6.
We critically review chemosensory conditioning studies with molluscs and find that, in many studies, the influence of nonassociative
processes complicates, obscures, and renders ambiguous the unique contribution of associative learning. These nonassociative
processes include sensory adaptation, habituation, sensitization, and changes in feeding motivation. They arise from both
the food extracts that have often been used as conditioned stimuli and the aversive stimuli that have been used as unconditioned
stimuli. 相似文献
7.
In Experiment 1, four groups of male rats were given a session as an intruder in either aggressive (i.e., alpha) or nonaggressive colonies of conspecifics and later received either a 2-h exposure to the odors of the alpha colonies or an exposure-control session with the odors of a nonalpha colony. Two additional groups of rats that had been attacked and defeated by alpha residents were later given a 12-h exposure session with alpha-colony odors or nonaipha-control odors. Twenty-four h after the colony-intruder session, all subjects were given a single 6.5-mA shock from a prod with alpha-colony odors present in the bedding of the test chamber. Attacked rats that had been given exposure-control sessions showed significantly less prod burying and greater freezing than nondefeated subjects. This implies that the alpha-colony odors elicited conditioned fear. In contrast, the attacked subjects that had been given a pretest exposure session with alpha-colony odors showed significantly more prod burying and significantly less freezing. This suggests that the alpha-odor exposure resulted in the extinction of fear to these odors. Furthermore, the 12-h exposure to alpha-colony odors was found to be more effective in reducing fear-mediated responses than was the 2-h exposure. In Experiment 2, three groups of rats were exposed to a cat while they were in a protective cage; later they were given a 12-h exposure session with cat odors, a 12-h exposure-control session with no cat odors, or no exposure treatment. Compared with the two control groups, the subjects that were exposed to cat odors showed less freezing during subsequent prod-shock tests in the presence of cat odors, but they did not show prod burying. The reported changes in fear-mediated reactions to the odors of conspecifics and a predator are discussed in terms of both associative and nonassociative processes. 相似文献
8.
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
9.
In Experiment 1, olfactory bulbectomized and control rats were trained using operant conditioning to determine the taste threshold of aqueous amyl acetate. Concentrations below gustatory threshold were used in Experiments 2–5 to compare the effectiveness of odors with various concentrations of saccharin as cues for illness. The results showed the following: (1) The effectiveness of odor and taste was directly related to concentration; (2) the strength of an aversion to a concentration of taste could be matched by an appropriate concentration of an odor; (3) odor was as effective as taste with CS-US delays of 4 h; and (4) an effective odor potentiated an aversion to an otherwise ineffective taste. The results challenge the privileged role accorded tastes in food aversion learning and the manner in which tastes are held to interact with odors according to the sensory-and-gate channeling analysis of potentiation (Rusiniak, Hankins, Garcia, & Brett, 1979). 相似文献
10.
Richard E. Brown 《Learning & behavior》1991,19(1):18-28
Two experiments investigated the effects of isolation rearing on olfactory communication in rats. In Experiment 1, there were significant rearing and gender effects on the time spent investigating conspecific odors, the preferences for these odors, and the amount of urine marking over these odors by sexually naive male and female rats. Experiment 2 found significant effects of rearing condition and sexual experience on the responses of male rats to conspecific odors. In general, isolation rearing increased the time spent investigating conspecific odors, but reduced the amount of urine marking over these odors and altered the odor preference scales. These results suggest that the responses of both male and female rats to the odors of conspecifics are modified by rearing experience. The importance of learning conspecific odor signals for the development of normal social behavior is discussed. 相似文献
11.
In these experiments, we investigated the nature of potentiation in the conditioned flavor preference paradigm. Almond and banana extracts, which have strong odor components, were combined with salt and saccharin (liked tastes; Experiment 1) or quinine and citric acid (disliked tastes; Experiment 2) in a flavor preference procedure that mixed these solutions with a caloric reinforcer (polycose). The results showed that liked tastes potentiated preference conditioning to extracts (Experiment 1), whereas extracts potentiated preference conditioning to disliked tastes (Experiment 2). In both experiments, the presumably less liked stimulus (i.e., the extract in Experiment 1 and the disliked taste in Experiment 2) was the potentiated cue. 相似文献
12.
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
13.
In Experiment 1, the amount of time rats spent engaged in a range of behaviors was recorded immediately prior to and following the intraperitoneal administration of morphine sulfate (6 mg/kg) or distilled water. No behavioral differences were observed between these groups. In Experiment 2, preexposure to this low dose of morphine attenuated the subsequent acquisition of a morphine-induced taste aversion independent of the similarity of the preexposure and conditioning environments. These results with a dose of morphine that does not produce any behavioral effects, which in turn could potentially mask associative conditioning during preexposure, confirm that the attenuating effects of morphine preexposure on taste aversion learning are nonassociative. 相似文献
14.
Past experiments have reported that rats encountering reward (R) or nonreward (N) goal events emit odors that can be utilized as discriminative stimuli for instrumental behavior by conspecifics. In the present study, thirsty male rats were aversively conditioned by ingestional toxicosis to R and N odors, and their suppression of water consumption in the presence of these odors was measured. Thirsty trained donors were placed into chambers containing R or N goal events to generate, respectively, the R or N odors. Test animals were given eight differential conditioning trials (four with one odor as CS+; four with the other as CS?), involving placement into an odorcontaining chamber with water available, followed by a LiCl injection on CS+ trials. Animals tested in their CS+ odor consumed significantly less water than did CS? and control subjects. Both R and N odors were conditioned by aversive means and readily discriminable from each other. This represents the first laboratory demonstration of aversive conditioning of such naturally produced odors, and it suggests that aversive conditioning may be useful in the study of odorous emissions generally. Implications for innate meanings of R and N odors are discussed. 相似文献
15.
The acquisition of conditioned taste aversion was assessed relative to five control procedures. That is, forward conditioning using multiple-trial, brief-duration taste CSs and weak USs over a 30-min CS-US delay was compared to backward, CS alone, US alone, sham CS and sham US, and random control procedures. The outcome supported an associative conditioning interpretation of the learned aversion. While there were no differences between the various control procedures, all were different from the forward conditioning group. The argument was made that some of the distinctive associative and nonassociative phenomena attributed to taste aversion conditioning (but not seen in the present study) may in part be due to the duration and intensity of both the CS and US events. 相似文献
16.
The primary purpose of the present study was to assess the ontogeny of nonassociative learning and memory in 16-, 30-, and 75-day-old rats. In each of three experiments, habituation of the orienting response to a novel auditory stimulus was measured. The orienting response is an unconditioned reaction elicited by innocuous environmental stimulation that habituates with repeated stimulus presentations. Both an autonomic component (heart-rate deceleration) and a behavioral index (head jerk) of the orienting response were recorded in this study. Although no age differences in rate of habituation (i.e., rate of nonassociative learning) were found (see Experiment 1), a marked effect of age on retention of habituation was observed. Preweanling rats retained habituation of the orienting response to an auditory stimulus for less than 4 h (Experiment 2), whereas adult animals exhibited no forgetting even after a 1-week interval (Experiment 3). These results are discussed in terms of (1) demonstrations of age-related differences in associative memory, (2) the persistence of nonassociative memories in adults, and (3) the significance of the orienting response as a measure of retention of nonassociative learning. 相似文献
17.
Recognition of maternal axillary odors by infants 总被引：6，自引：0，他引：6
A series of 5 experiments was conducted to determine whether neonates, at approximately 2 weeks of age, can recognize their parents through axillary odors alone. Breast-feeding infants discriminated between their mother's axillary odor and odors produced by either nonparturient or unfamiliar lactating females. In contrast, breast-feeding infants displayed no evidence of recognizing the axillary odors of their father. Likewise, bottle-feeding infants appeared unable to recognize the odor of their mother when presented along with odors from a nonparturient female or an unfamiliar bottle-feeding female. Several hypotheses were presented in an attempt to account for the differential reactions to maternal odors by breast-feeding versus bottle-feeding infants. It was tentatively concluded that, while breast-feeding, infants are exposed to salient maternal odors and thereby rapidly become familiarized with their mother's unique olfactory signature. 相似文献
18.
In three experiments with rats, taste + odor interactions in compound aversion conditioning were investigated. In Experiment 1, two odors (0.02% almond and 0.02% orange) were compared on single-element odor aversions, taste (denatonium) potentiated odor aversions, and potentiated odor aversions following taste extinction. Although no odor differences were seen following single-element conditioning, both types of potentiated orange odor aversions were stronger than their almond odor counterparts. These data show that odors of similar conditionability are differentially potentiated by the same taste. To determine whether these differences were due to unique perceptual representations, the effects of elemental extinction or compound extinction on aversions to the compound were investigated in Experiments 2 and 3. In Experiment 2, orange odor extinction weakened responding to the compound significantly more than taste extinction did. In contrast, almond odor extinction and taste extinction produced similar decrements in responding to the compound in Experiment 3. These results suggest that the perceptual representation of these specific taste + odor compounds are different, and they are discussed in regard to configural and within-compound association accounts of potentiation. 相似文献
19.
Tolerance to morphine-induced hypoactivity in hamsters was investigated under conditions designed to test a Pavlovian conditioning model of morphine tolerance. One group of animals received i.p. injections of morphine (50 mg/kg) in the test environment and saline in the home cage; a second group received saline in the test environment and morphine in the home cage; a third group received saline in both environments. A subsequent morphine challenge in the test environment gave evidence of both associative and nonassociative tolerance. Associative tolerance was detectable 1 week later during a second morphine challenge. Compensatory hyperactivity, however, was not observed during a saline challenge in the presence of morphine-associated cues. Following the acquisition of tolerance, nonreinforced exposure to morphine-associated cues produced an attenuation of morphine tolerance (i.e., extinction of tolerance). The results are interpreted as providing partial support for the Pavlovian model and are discussed in terms of alternative associative models of tolerance. 相似文献
20.
In Experiment 1, male rats were exposed to either aggressive (i.e., alpha) or nonaggressive conspecific colonies and tested 24 h later, with or without alpha odors, for freezing behavior and burying of a wall prod that had been the source of a brief electric shock. The results indicated that prior defeat experience and the presence of alpha odors alone during testing had no significant effects, but the combination of prior defeat and alpha-odor testing significantly decreased burying and increased freezing behavior. In Experiment 2, we examined the effects of noncontact exposure to a cat, as a predatory Stressor, during subsequent prod-shock tests involving the presence or absence of cat odors. Exposure to a cat failed to disrupt later prod burying and did not produce freezing. However, the presence of cat odors during testing significantly reduced the amount of defensive burying,without resulting in an increment in freezing. In Experiment 3, rats were given 1, 5, or 30 inescapable preshocks in the presence of either cat odors or a hedonically neutral citronella odor and were tested 24 h later for prod burying and freezing with or without these odors. Both the cat and the citronella odors resulted in a significant reduction in burying and an increase in freezing for rats given 5 and 30 preshocks and tested in the presence of these respective conditioned odors. For the groups that were given 5 preshocks, preshock and later testing in the presence of cat odors resulted in significantly less prod burying and more freezing than for rats that were preshocked and tested in the presence of citronella. The findings of these three ethoexperimental studies are discussed in terms of the learned-helplessness theory, the stress-coping-fear-defense (SCFD) theory, and the concept of selective CS-US associability. 相似文献