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1.
Nonreinforced exposure to a nontarget stimulus that was followed by nonreinforced exposure to a target/nontarget simultaneous
compound stimulus resulted in enhanced latent inhibition of the target. Conditioning was slower after this treatment than
after nonreinforced exposure to the target stimulus alone (Experiment 1). However, a salient auditory stimulus presented immediately
after the compound in the second phase reduced levels of latent inhibition, relative to the enhanced latent inhibition produced
when no such extracompound stimulus was presented (Experiments 2 and 3). This effect was not noted if the salient auditory
cue was presented 10 sec after the termination of the compound stimulus (Experiment 4). In Experiment 5, there was no disruption
of simple latent inhibition produced by a salient stimulus. These results are consistent with enhanced latent inhibition’s
being produced by the formation of within-compound associations, which are disrupted by the salient extracompound stimuli. 相似文献
2.
Two experiments examined the effects of nonreinforced flavor exposure on the strength of a conditioned taste aversion. Rats were conditioned by pairing maple flavor with LiC1. Prior to or subsequent to this pairing, some animals received nonreinforced exposure to either maple or saccharin. In separate subjects, preference for maple was tested 1 or 21 days after the last training episode. In the first experiment, the nonreinforced stimulus exposure occurred before conditioning (latent inhibition, or LI, procedure); in the second experiment, the nonreinforced exposure occurred after conditioning (extinction, or EXT, training). In both experiments, nonreinforced exposure to maple or saccharin reduced the magnitude of a conditioned maple aversion when testing occurred soon after conditioning. When testing was delayed, however, the attenuation due to nonreinforced saccharin exposure dissipated, both with the LI procedure and with EXT. In contrast, the nonreinforced exposure to maple was found to attenuate conditioned reactions at both short and long retention intervals. The release from generalized LI and spontaneous recovery following generalized EXT training are discussed in terms of retrieval processing. The possibility that the same mechanism may underlie LI and EXT is considered. 相似文献
3.
In two experiments using the taste-aversion paradigm, we attempted to replicate a result reported by Holland and Forbes (1980), in which exposure to the elements of a compound produced more interference with future conditioning (latent inhibition) to the compound than did exposure to the compound itself. In our first experiment, a compound of HC1 and sucrose was used and the amount of fluid consumed during exposure and the first conditioning trial was controlled. Rather than finding enhanced interference produced by exposure to the elements, we found reduced interference relative to exposure to the compound. In Experiment 2, a compound of NaCl and sucrose was used and a method similar to that used by Holland and Forbes was employed. We replicated the result of our Experiment 1. We interpret these results as posing problems for some associative accounts of latent inhibition but as being easily explained as an instance of stimulus generalization decrement. 相似文献
4.
Water-deprived adult rats were used in a conditioned-suppression-of-licking procedure to determine the effect of inhibitory training with a novel stimulus trained in simultaneous compound with a previously established conditioned inhibitor. This procedure constitutes an inhibitory analogue to the excitatory blocking procedure in classical conditioning. The conditioned-inhibition training consisted of either explicitly unpaired CS and US presentations or negative contingency training, in which the likelihood of the US was greater in the absence than in the presence of the CS, but the CS and the US were occasionally paired. To assess conditioned inhibition, a retardation test was used, and comparable retardation was obtained for subjects that were administered the blocking treatment and control subjects given similar conditioned-inhibition training with a compound stimulus in which the nontarget element was not previously established as a conditioned inhibitor. 相似文献
5.
Conditioned attention theory (CAT) of latent inhibition (LI) states that parallel learning processes occur during reinforced and nonreinforced stimulus presentation. The present experiments investigated the effects of nonreinforced preexposure of either a compound CS or elements of that compound which differed in salience. Three predictions were advanced: (1) Both the compound and its elements will show an increase in LI as a function of the number of preexposures; (2) the two elements will show different levels of LI, with more LI accruing to the more salient element; (3) overshadowing will occur during compound preexposure. Two experiments, using rats as subjects and a conditioned suppression test, are reported. In Experiment 1, groups received 0, 20, 40, or 80 nonreinforced preexposures to a compound whose elements differed in salience. The results of the subsequent test confirmed predictions 1 and 2. Experiment 2, in which groups were preexposed to either the elements or the compound, provided evidence for an overshadowing effect, confirming prediction 3 from CAT. 相似文献
6.
The roles of deficient acquisition and deficient expression of learned information in the effect of relative stimulus validity were examined using rats in a conditioned lick suppression paradigm. Recovery from the effect without further pairings of the conditioned stimulus (CS) and the unconditioned stimulus (US) would favor an interpretation of the relative validity effect based on a latent CS-US association as distinct from a failure to acquire the CS-US association. As a potential recovery manipulation, “reminder” treatments, consisting of the US alone (Experiment 1) or the CS alone (Experiment 2), were administered following relative validity training. In both cases, subjects for which the CS target was of low relative predictive validity exhibited enhanced responding relative to appropriate controls. Additionally, Experiment 2 showed that the amelioration of the relative validity deficit was stimulus specific. Thus, the results of these experiments support previous suggestions that the performance deficit resulting from low relative stimulus validity is due, at least in part, to a failure to express acquired information (Cole, Barnet, & Miller, 1995a). 相似文献
7.
Rats were used in a conditioned-suppression paradigm to determine whether an extinction treatment would enhance a moderately developed conditioned inhibitor (CS?). To dissipate unconditioned suppression to the training stimuli, the subjects were first habituated to the stimuli and then given Pavlovian conditioned-inhibition (CI) training involving reinforced presentations of a clicker and nonreinforced compound presentations of that stimulus and the intended CS?, either a light or a tone. Thereafter, experimental subjects received presentations of their CS? by itself, whereas controls received no further training. Following the occurrence and loss of conditioned suppression to the CS? in the extinction phase, summation and retardation tests showed enhanced CI for the experimental subjects relative to both the controls and their own earlier levels of inhibitory performance. In fact, the enhanced inhibition for the experimental subjects approximated that shown by a comparison group for which the CS? had been strongly developed as an inhibitor. These findings suggest that an excitatory representation is associated with the CS? early in CI training, and that subsequent presentations of the CS? by itself strengthen its inhibitory effect by allowing it to be nonreinforced in the presence of that representation. 相似文献
8.
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
9.
Robert A. Rescorla 《Learning & behavior》1983,11(4):439-446
Five experiments used an autoshaping procedure with pigeon subjects to explore the consequences of separate-element presentation for within-compound associations. When a keylight compound had initially been reinforced, separate presentation of one element reduced responding to the other. This was true whether that separate-element presentation was itself reinforced or nonreinforced. That suggests that the detrimental effect of separate-element presentation results from an effect on the within-compound association, rather than one on the association of either element with the US. When the compound had initially been nonreinforced, a moderate level of reinforcement of one element resulted in responding to the other element. However, more extensive reinforcement reduced that responding. Moreover, an attempt to reverse the adverse consequences of extensive separate-element presentation by further exposure to the compound was not successful. These results comment on the associative mechanisms underlying performance in sensory preconditioning and related paradigms. 相似文献
10.
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
11.
In three between-groups blocking experiments with rats, two concurrent and one forward, several common control procedures
were employed: Reinforced trials with the putative blocking stimulus were either omitted entirely (Kamin control), replaced
by unsignaled reinforcements (Wagner control), or replaced by reinforced trials with a different stimulus (C1 control). In
each experiment, parallel treatments with the target stimulus absent during training served to examine the possibility that
differential responding in tests with the target stimulus might be traced solely to differential exposure to the nontarget
stimuli. In Experiment 1, responding by a concurrent blocking group during the test was no different than responding by a
Kamin control group, and responding by a Wagner control group was greater than that of either of the other groups—a pattern
of results, mirrored in the performance of the target-absent groups, that could be attributed to the elevation of contextual
excitation by unsignaled reinforcement. In Experiment 2, responding in the test by a concurrent blocking group was no different
than that by a C1 control group. In Experiment 3, a finding of less responding by a forward blocking group than by a C1 control
group when the target stimulus was present during training, but not when it was absent, provided plausible evidence of blocking. 相似文献
12.
Three experiments with rat subjects examined the development of simultaneous and serial feature-positive discriminations in appetitive conditioning. In Experiment 1, reinforced presentations of a simultaneous light-tone compound were intermixed with nonreinforced presentations of either the light or the tone. The compound stimulus acquired conditioned behaviors of a form characteristic of the predictive feature alone; the element common to reinforced and nonreinforced trials did not evoke conditioned behavior. In Experiment 2, reinforced presentations of a serial light-trace-tone compound were intermixed with nonreinforced tone-alone presentations. The light feature stimulus acquired conditioned behaviors characteristic of visual CSs. The tone stimulus, common to reinforced and nonreinforced trials, evoked conditioned behaviors characteristic of auditory CSs, but only when preceded by the light. In Experiment 3, variations in the interval between the light and tone on reinforced trials had little effect on responding to the light CS but substantially altered the pattern of responding to the tone CS. These results suggested that simultaneous and serial feature-positive discriminations may be solved differently. Performance in simultaneous feature-positive discriminations may be determined solely by associations between the feature stimulus and the reinforcer, but performance in serial discriminations may also involve the acquisition of a conditional cue function to the feature. 相似文献
13.
Robert A. Rescorla 《Learning & behavior》1999,27(2):140-151
In four experiments, rat subjects were used in appetitive Pavlovian magazine-approach and instrumental conditioning procedures. Experiments 1 and 2 found successful blocking of the Pavlovian conditioning of X when it was reinforced in an AX compound after prior conditioning of A. This occurred whether the outcome following AX was the same as or qualitatively different from what followed A. Experiment 3 repeated those findings but also used a transfer procedure to identify the individual associations between X and outcomes. Stimulus X developed an association with the outcome following AX when that outcome differed from that following A alone but not when it was the same as that following A alone. Experiment 4 repeated that pattern of observations for the case of an X that was an instrumental discriminative stimulus. These results suggest that different associative structures may result from a qualitatively changed and unchanged outcome in a blocking experiment. The results are related to comparable findings for the case of overexpectation. 相似文献
14.
Two experiments were performed using rats in a conditioned suppression procedure to test two different methods for extinguishing Pavlovian conditioned inhibition. In both experiments, a target stimulus, X, was made inhibitory by giving discrimination training of the form A+ AX?. Then, in Experiment 1, an attempt was made to extinguish the inhibition conditioned to X by presenting nonreinforced occurrences of X, of AX, and of A. Testing for conditioned inhibition took the form B+ BX?. It was found that the extinction procedure did not weaken the inhibitory properties of X. Experiment 2 attempted to extinguish the inhibition conditioned to X by presenting X randomly and independently of the reinforcer, electric grid shock. This procedure appeared to weaken inhibition quickly and permanently. 相似文献
15.
A classical conditioning procedure was instituted in which the locus of the US was changed coincidentally with the onset of the compound conditioning phase of the Kamin blocking design. The nictitating membrane of the rabbit served as the conditioning preparation. Three groups of nine rabbits each were employed: a conventional blocking group in which the US was unchanged during the simple and compound conditioning phases, a control group that received only the compound conditioning phase, and an experimental group given both simple and compound conditioning but in which the US was administered to the contralateral paraorbital region during the compound conditioning phase. Postconditioning presentations of the elements of the compound CS indicated that, relative to the control group, responding during the new element was markedly reduced in the conventional blocking group but was strongly conditioned in the group in which the US locus was changed. Implications of these findings for theoretical analyses of conditioning are discussed. 相似文献
16.
Foraging honeybees were trained in a concurrent blocking design with a compound stimulus (AX) reinforced and one of its components (A) either reinforced for a blocking group or nonreinforced for a control group. In Experiment 1, a compound of two colors was used; in Experiment 2, a compound of two odors was used; in Experiment 3, a color-position compound, with position defined in terms of proximity to a distinctive visual landmark, was used; and, in Experiment 4, an odor-position compound was used. In each of the first three experiments, the blocking group responded less than did the control group in a subsequent test with X; in the fourth experiment, the two groups did not differ. The results are in accord with expectations based on those of previous experiments with honeybees in which the independence assumption was found to hold for intermodal compounds but not for intramodal compounds. 相似文献
17.
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
18.
Three experiments examined rats’ ability to discriminate a compound conditioned stimulus (CS) from the individual elements of that compound in a flavor aversion conditioning paradigm. In Experiment 1, presentations of a compound of sucrose and saline solutions were followed by lithium chloride injections, but presentations of those elements individually were nonrein-forced (positive patterning). Conversely, in Experiments 2 and 3, presentations of the individual elements were followed by lithium chloride injection, but compound presentations were non-reinforced (negative patterning). The discriminations were acquired in all three experiments. In addition, all three experiments investigated the effects of preexposure of the discriminative stimuli on subsequent acquisition of the patterned discriminations. In positive patterning, preexposure had no measurable effect on the acquisition of responding (suppression) to the reinforced compound stimulus, but slowed the loss of suppression to the nonreinforced elements. In negative patterning, preexposure slowed the acquisition of suppression to the reinforced elements but had little effect on the loss of suppression to the nonreinforced compound. 相似文献
19.
Rats were subjected to the Kamin two-stage blocking procedure. First, a stimulus, A, was conditioned and then reinforced in compound with a target stimulus, B. During compound training, an attempt was made to alleviate blocking of conditioning to B by presenting a “surprise” stimulus for 5 sec following the reinforced AB compound. The surprise stimulus consisted of the continued presentation of the previously reinforced element, A. During A training, A had never extended beyond the moment of reinforcement; thus, its extension beyond reinforcement during AB training was hypothesized to be “surprising” and, therefore, expected to alleviate blocking. Blocking in this condition was, however, just as strong as in a standard blocking condition. The results do not favor a surprise interpretation of unblocking but do seem to be consistent with other theoretical views (e.g., Rescorla & Wagner, 1972). 相似文献
20.
Daniel Tomsic María E. Pedreira Arturo Romano Gabriela Hermitte Héctor Maldonado 《Learning & behavior》1998,26(2):196-209
An opaque screen moving overhead elicits an escape response in the crabChasmagnathus that habituates for a long period after just a few presentations. A series of experiments was performed to determine whether the crab’s long-term habituation (LTH) is mediated by an association between contextual cues and the eliciting stimulus.Chasmagnathus failed to exhibit LTH when a visual cue in the experimental environment was changed between training and testing. In addition, long-term exposure to the context in the absence of the eliciting stimulus impaired LTH, both when the exposure preceded the habituation training (latent inhibition) and when the exposure came after the training (extinction). Long exposure to the context alone prior to training also produced a decrease in responsiveness to the eliciting stimulus, which confirmed previous results. However, both effects of long exposure were only manifested when the crabs spent a period of time between exposure and testing out of the experimental context. The results of this paper are interpreted as supporting the view thatChasmagnathus LTH can be understood largely by Wagner’s associative theory of habituation. 相似文献