共查询到20条相似文献，搜索用时 46 毫秒
1.
Four experiments examined generalization of latent inhibition (LI) as a function of the length of preexposure in a conditioned
taste aversion procedure with rats. Experiment 1 showed that one or four nonreinforced presentations of a flavor compound (BX) retarded subsequent conditioning to another
compound (AX). However, after eight presentations of BX, conditioning to AX occurred at the same rate as with no preexposure.
These results indicate that generalization of LI decreased as the length of preexposure to BX increased. Experiment 2 replicated this effect of reducing generalization, as well as demonstrating that LI actually increased as the length of preexposure
to AX increased. Experiment 3 extended the generality of the effect to a procedure in which both BX and AX were preexposed. Experiment 4 demonstrated a similar reducing-generalization effect when generalization of LI from BX to X was assessed. All of these data
are consistent with the notion that prolonged preexposure to BX enhances its discriminability. Different learning mechanisms
that might be responsible for this perceptual learning effect are discussed. 相似文献
2.
In three conditioned taste aversion experiments, we examined the roles of several variables in producing super-latent inhibition (LI). This effect, greater LI after a long interval than after a short interval between the conditioning and the test stages (De la Casa & Lubow, 2000), was shown to increase with the number of stimulus preexposures (0, 2, or 4; Experiment 1) and with the length of the delay interval (1, 7, 14, or 21 days; Experiment 2). Furthermore, super-LI was obtained when the delay interval was introduced between the conditioning and the test stages (Experiments 1 and 2), but not when it was introduced between the preexposure and the conditioning stages (Experiment 3). The results are discussed in relation to interference explanations of LI. 相似文献
3.
Two experiments with rat subjects examined conditioning of an aversion to a compound flavor stimulus after preexposing the compound, its constituent elements, or no explicit flavor stimulus. Experiment 1 used a short-term procedure in which preexposure and conditioning treatments occurred on the same day; Experiment 2 used a long-term procedure in which more extensive preexposure was administered several days before conditioning. In both experiments, preexposure of the elements slowed conditioning to the compound more than did preexposure of the compound itself. These effects were apparently not mediated by changes in pseudoconditioned or neophobic responses. The results were related to Lubow’s conditioned attention theory of stimulus preexposure effects. 相似文献
4.
In Experiment 1, rats received single-alternation training with 32% or 4% sucrose reward (Phase 1) followed by a shift in reward from 32% to 4%, and vice versa (Phase 2). In Phase 1, high reward facilitated alternation performance over low reward. In Phase 2, performance on rewarded trials increased as reward increased but was unchanged as reward decreased. Performance on nonrewarded trials showed negligible effects of shifts in reward. In Experiment 2, rats received goalbox placements with 32% or 4% sucrose alternated with nonreward in Phase 1; and in Phase 2, they received alternation runway training with the same or the opposite reward from that of placements. Performance on rewarded trials was faster, the higher the reward in runway training; performance on nonrewarded trials was slower, the higher the reward in placements. In Experiment 3, Phase 1 provided placements with 64%, 32%, 16%, or 4% sucrose or dry mash alternated with nonreward; Phase 2 provided alternation runway training with dry mash reward. Alternation prerformance developed more rapidly, the higher the sucrose concentration in placements. Only 64% sucrose produced performance superior to that for dry-mash placements. 相似文献
5.
Four experiments used a within-subjects design with rats to study the effects of preexposure on the restoration of fear responses
(freezing) to an extinguished conditioned stimulus (CS). In each experiment, rats were preexposed to one CS (A), but not to
another (B), and then were exposed to pairings of each of these CSs with an aversive unconditioned stimulus (US). In each
experiment, there was less freezing to A than to B across extinction, showing a latent inhibitory effect of preexposure. There
was no differential recovery to A and B following either a US reexposure (Experiment 1) or a delay interval (Experiment 2). However, when a delay interval included US reexposure, there was greater recovery to the preexposed CS, A, than to the
nonpreexposed CS, B (Experiments 1, 3, and 4). These results suggest that the effects of US reexposure and delay combine to affect recovery from the depressive effects
of CS-alone exposure. The results are consistent with the view that US reexposure produces better mediated conditioning of
CSs that are strongly associated with the context. The results may additionally reflect an effect of preexposure on the learning
produced by extinction. 相似文献
6.
Michael Domjan 《Learning & behavior》1978,6(2):133-142
Taste aversions were conditioned by exposing subjects to a 1.0% saccharin solution 30 min after an injection of lithium chloride. The aversion learning was disrupted if subjects had also received an additional lithium injection some time earlier (Experiments 1–3). This interference effect of US preexposure was a decreasing function of the preexposure interval, beyond the optimal interval (105 min) for observing the phenomenon (Experiment 1), and was directly related to the dose of the preexposure injection (Experiment 2). No interference with conditioning occurred at short (e.g., 30-min) preexposure intervals (Experiment 1), probably because under these circumstances the preexposure injection itself conditioned a strong aversion (Experiment 4). At moderate (105-min) but not at short (30-min) preexposure intervals, the interference with aversions learned as a result of taste exposure following drug injection was comparable to the interference with learning in a more conventional forward conditioning procedure (Experiments 3 and 4). These findings are similar to previously documented effects of proximal CS- and US-preexposure and are consistent with recent stimulus rehearsal and opponent-process theories. 相似文献
7.
Nicholas J. Grahame Robert C. Barnet Lisa M. Gunther Ralph R. Miller 《Learning & behavior》1994,22(4):395-408
Treatments that attenuate latent inhibition (LI) were examined using conditioned suppression in rats. In Experiment 1, retarded conditioned responding was produced by nonreinforced exposure to the CS prior to the CS-US pairings used to assess retardation (i.e., conventional LI). In Experiment la, retarded conditioned responding was induced by preexposure to pairings of the CS and a weak US prior to retardation-test pairings of the CS with a strong US (i.e., Hall-Pearce [1979] LI). Both types of LI were attenuated by extensive exposure to the training context (i.e., context extinction) following the CS-US pairings of the retardation test. Experiment 2 examined the specificity of the attenuated LI effect observed in Experiment 1. After preexposure to two different CSs in two different contexts, each CS was paired with a US in its respective preexposure context. One of the two contexts was then extinguished. This attenuated LI to a greater degree for the CS that had been trained in the extinguished context. Experiment 3 differentiated the roles in LI of CS-context associations and context-US associations. Following preexposure to the CS in the training context, LI was reduced by further exposure to the CS outside the training context. This observation was interpreted as implicating the CS-context association as a factor in LI. Thus, the results of these experiments suggest that LI is a performance deficit mediated by unusually strong CS-context associations. Implications for Wagner’s (1981) SOP model and Miller and Matzel’s (1988) comparator hypothesis are discussed. 相似文献
8.
Aversive conditioning was studied in individual honeybees flying back and forth between the hive and the sill of an open laboratory window, where they took sucrose solution from a target so constructed that shock could be delivered while the proboscis was in contact with the solution. During feeding, a conditioned stimulus—substrate vibration or airstream—was paired with brief shock avoidable by interruption of feeding. In Experiment 1, unreinforced preexposure of the conditioned stimulus was found to retard acquisition (latent inhibition). In Experiment 2, which was designed to inquire into the stimulus specificity of the effect, differential conditioning was found to be impaired by unreinforced preexposure of the positive stimulus and facilitated by unreinforced preexposure of the negative stimulus. In Experiment 3, a summation experiment designed to test various alternative explanations of the effect, a preexposed stimulus was found to suppress response to an excitatory conditioned stimulus when the two stimuli were presented together. 相似文献
9.
Philipp J. Kraemer Christopher K. Randall Timothy J. Carbary 《Learning & behavior》1991,19(2):139-145
A conditioned emotional response procedure was used to study the interactive effects of stimulus preexposure and retention interval in rats. In Experiment 1, the subjects were conditioned by presenting a light CS paired with mild footshock as the US. Half of the subjects were given nonreinforced preexposure to the CS, and the others were not. Separate preexposed and nonpreexposed groups were then tested 1,7, or 21 days after conditioning. Suppression of ongoing activity was used to assess the degree of conditioned fear. Latent inhibition was found at the 1-day retention interval; the preexposed subjects displayed less conditioned fear than did the nonpreexposed subjects. In contrast, equally strong conditioned fear was expressed by the preexposed and the nonpreexposed groups tested after the 7- and the 21-day retention intervals. These results indicate a release from latent inhibition similar to that obtained with conditioned taste aversions (Kraemer & Roberts, 1984). The results of Experiment 2 suggest that retention-interval-induced increases in sensitization, pseudoconditioning, or neophobia cannot account for the release from latent inhibition effect obtained in Experiment 1. The implications of these findings for a retrievaloriented view of latent inhibition are discussed. 相似文献
10.
Wallace R. McAllister Dorothy E. McAllister Stephen E. Dieter James H. James 《Learning & behavior》1979,7(2):165-173
In Experiment 1, four groups of subjects (n = 16 each) were exposed to the situational stimuli of a shuttlebox apparatus for 4 h. Subsequently, 200 two-way avoidance trials were administered (100/day) with either .3- or 1.6-mA shock and with either small or large reward (presence or absence of visual stimuli following the response). Avoidance performance was directly related to shock intensity on both days and to magnitude of reward on the 2nd day. In Experiment 2, four groups of subjects (n = 24 each) were given 4 h of exposure either to the situational stimuli of the shuttlebox or to a neutral box. Then, 10 two-way avoidance trials were given with 1.6-mA shock. Subsequently, subjects were allowed to escape from one of the shuttlebox compartments to an adjacent safe box. Following preexposure to situational stimuli, avoidance performance was superior whereas escape-from-fear performance was inferior. This latter finding demonstrated that less fear of situational cues was present during avoidance training in the preexposed condition. All of these results support the effective reinforcement theory, an extension of two-factor theory, which emphasizes the importance for avoidance learning of the amount of fear of situational cues present following a response. 相似文献
11.
Animals were first conditioned to expect lithium treatment following exposure to one taste solution (the CS+) and to expect no drug treatment following exposure to another flavor (the CS?). All subjects then received a saccharin taste-aversion conditioning trial. In Experiment 1, this conditioning trial was preceded 0, 1, 2, 4, or 6 h earlier by exposure to the CS+ flavor for independent groups. The CS+ exposure attenuated saccharin aversion learning if it occurred immediately before the saccharin conditioning trial but not if it occurred 1 h or more before conditioning. In Experiment 2, the saccharin conditioning trial was preceded 3 or 4.5 h earlier by a lithium injection. This proximal US preexposure injection was either unannounced (Li) or preceded by exposure to the CS+ (CS+Li) or the CS? (CS?Li) stimuli. The US preexposure attenuated saccharin aversion learning in all cases. However, the interference effect was less when the preexposure injection was expected (CS+Li) than when it was unexpected (CS?Li). This outcome could not be explained in terms of direct effects of the CS+ and CS? stimuli on the saccharin conditioning trial, and shows that the proximal US preexposure effect is a function of not only the drug dosage and preexposure interval, but also the anticipation of the drug pretreatment. 相似文献
12.
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
13.
Pentobarbital is self-administered by rats but has also been reported to produce a conditioned place aversion. Since the self-administration and place preference paradigms both are considered to assess drug reward, we further examined the hedonic properties of pentobarbital, using place conditioning. In Experiment 1, a dose of 15 mg/kg (intraperitoneal) of pentobarbital produced a conditioned place aversion after 4 conditioning trials of various durations (5, 15, 30, or 60 min). Since rats are typically drug experienced in the self-administration paradigm, in Experiments 2 and 3, we examined the effect of drug history on pentobarbital-induced place conditioning. Although preexposure to pentobarbital attenuated the place aversion, it never resulted in a place preference. As has been reported with alcohol, pentobarbital is hedonically aversive in rats, when novel. 相似文献
14.
Three experiments showed a savings procedure to be an effective and sensitive alternative to sensory preconditioning procedures as a measure of associations among neutral stimuli. Experiment 1 showed that within-compound associations developed more rapidly in reinforced appetitive serial compound conditioning when nonreinforced preexposure to the serial compound was given than when separate element or no preexposure was given. Experiment 2 showed the savings effect to be highly stimulus specific. Experiment 3 examined the facilitation of serial compound conditioning after either simultaneous or serial nonreinforced preexposure to the elements of the compound. The results of that experiment were consistent with those of analogous sensory preconditioning experiments. When preexposure involved only the two elements of the subsequently reinforced compound, serial preexposure produced more savings than simultaneous preexposure. But when preexposure involved a three-stimulus procedure like that used by Rescorla (1980b), simultaneous preexposure resulted in more savings. Advantages of the savings procedure over sensory preconditioning as a measure of association among neutral stimuli are discussed. 相似文献
15.
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
16.
The effect of morphine preexposure on place conditioning with morphine was investigated. In the first experiment, five injections of 10 mg/kg morphine were administered to rats prior to place conditioning or taste-aversion training with morphine. Although this number of preexposures retarded taste-aversion learning, there was no effect on place conditioning. In subsequent experiments we investigated the role of context blocking in UCS preexposure in place conditioning. In one experiment, preexposure to five morphine injections prior to place conditioning resulted in a reduced place preference, compared with preexposure and place conditioning in different contexts. However, the overall detrimental effect of morphine preexposure was questionable, because the rats that were preexposed were only marginally different from those that were not preexposed. In a final experiment we examined the effect of a context change from preexposure to place conditioning with 15 preexposures and demonstrated a detrimental effect of preexposure on place conditioning that was context specific. These results support a role of classical conditioning in place-preference conditioning with morphine. 相似文献
17.
In two experiments, we examined how preexposure to discriminative stimuli and introduction of a 21-day retention interval
affected the latent inhibition (LI) and perceptual learning (PL) of rats in a choice-maze discrimination task. Experimental
groups were preexposed to three wall patterns, one in each of three arms of a maze. Control groups were preexposed only to
white arms. PL groups were trained to discriminate A versus B, and LI groups, to discriminate A or B versus C. The A and B
patterns shared many elements not shared with the C pattern. In Experiment 1, both at the end of training and after the subsequent
retention interval, the PL groups performed better than controls, whereas the LI groups performed worse. In Experiment 2,
inserting the 21-day retention interval between preexposure and discrimination training disrupted final measures of LI but
not PL performance. Implications for current concepts of PL and LI are discussed. 相似文献
18.
Matías López Patricia Gasalla Mercedes Vega Cheryl L. Limebeer Erin M. Rock Katharine J. Tuerke Holly Bedard Linda A. Parker 《Learning & behavior》2010,38(2):177-186
The present experiments, using the latent inhibition (LI) paradigm, evaluated the effect of nonreinforced exposure to saccharin
on the acquisition of an LiCl-induced saccharin aversion as measured by conditioned disgust reactions in the taste reactivity
test and conditioned taste avoidance in a consumption test. When rats were preexposed to saccharin by bottle exposure (Experiments
1 and 3), LI was evidenced only by conditioned taste avoidance (bottle testing), but not by conditioned disgust reactions
(intraoral [IO] testing). On the other hand, when rats were preexposed to saccharin by IO infusion (Experiments 2 and 3),
LI was evidenced only by conditioned disgust reactions, but not by conditioned taste avoidance. Experiment 4 showed that LI
of conditioned disgust reactions does not appear to be affected by a context shift from preexposure to testing phases. These
results show that the expression of LI of both conditioned taste avoidance and conditioned disgust reactions depends critically
on a common method of flavor exposure during preexposure and testing. 相似文献
19.
Charles F. Flaherty Patricia S. Grigson Cynthia Coppotelli Colin Mitchell 《Learning & behavior》1996,24(1):68-81
Intake of a 0.15% saccharin solution was suppressed when it was followed by a 32% sucrose solution in brief daily pairings. With equal access durations to the two solutions, intervals of intermediate duration (2 or 3 min) produced a larger contrast than more extreme intervals (1 or 10 min). There was no evidence of inhibition of delay with the 10-min interval (Experiments 1A and 1B). When access times were asymmetrical, longer access time to the first solution reduced contrast, whereas longer access time to the second solution enhanced contrast (Experiment 2). Contrast was greater when the two solutions were presented at consistent and separate spatial locations than when location was changed randomly or when both solutions were presented in sequence at the same location. However, a degree of contrast occurred in all conditions (Experiment 3). Experiment 4, conducted with the solutions in opposite arms of a T-maze, showed that anticipatory approach to the location correlated with the 32% sucrose solution developed prior to lick suppression on the saccharin solution. However, within daily sessions, there was a reliable increase in contrast without correlated changes in anticipatory-approach behavior. Access-time effects were attributed to altered reward values, whereas spatial-separation effects suggest that goal-directed responses contribute to, but do not cause, anticipatory contrast. 相似文献
20.
In Pavlovian fear conditioning, context-mediated decrements in conditioned responding (e.g., the US preexposure effect) can
counteract competition between cues trained together (e.g., overshadowing). Two experiments were conducted using rats in a
conditioned lick suppression preparation to determine whether context-mediated competition also counteracts competition between
cues trained separately (retroactive interference, or RI). In Experiment 1, a combination of degraded contingency and RI treatments
produced less of a decrement in conditioned responding than did either of those treatments alone. Experiment 2 showed that
RI treatment attenuates the normally deleterious effect of trial massing. The results suggest that empirical similarities
are shared by interference between cues trained apart and competition between cues trained together. 相似文献