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1.
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
2.
Control of pigeons’ keypecking by conditionalities in the spatial arrangement of two element stimuli (designated A and B) was investigated. In Experiment 1, reinforcement for keypecking was made conditional upon the left-right location of A and B: Reinforcement was available when A was on the left and B was on the right (AB), but not on BA, AA, or BB trials. The pigeons successfully discriminated the rewarded AB configuration, but only after a stage in which a particular element in a particular location (e.g., A on left) primarily controlled pecking. Experiments 2 and 3 systematically replicated these findings and included controls to discount discrimination of the AB compound on the basis of the temporal order (e.g., A followed by B) rather than the spatial configuration of the elements. During a generalization test in Experiment 4, the elements were presented singly either in the left (AX, BX) or right (XA, XB) positions. As would be expected had the animals learned “A on the left, B on the right is rewarded,” responding on AX trials exceeded that on XA trials, and responding on XB trials exceeded that on BX trials. 相似文献
3.
Three conditioned lick suppression experiments with rats were performed to assess the influence, following compound training
of two stimuli (A and X) with the same outcome (AX-O trials), of extending training of the blocking association (i.e., A-O)
on responding to the target stimulus (X) at test. In Experiment 1, backward blocking was attenuated when the blocking association
was extensively trained. Experiment 2 showed that forward blocking was also attenuated by extensive further training of the
blocking association following the AX-O trials. Experiment 3 contrasted candidate explanations of the results of Experiments
1 and 2 and demonstrated that these results are consistent with the framework of the extended comparator hypothesis (Denniston,
Savastano, & Miller, 2001). 相似文献
4.
Rats received training in which two auditory target stimuli, X and Y, were signaled by two visual stimuli, A and B, and followed by food (i.e., A-->X+, B-->Y+). The test consisted of presentations of X and Y preceded either by the same signal as during training (same trials: A-->X, B-->Y) or by the alternative signal (different trials: A-->Y, B-->X). After 8 training sessions, the animals responded less on same trials than on different trials; this effect was significantly reduced after 24 training sessions. In two additional experiments, animals that had also experienced presentations of A and B alone, either before or during training, showed the opposite pattern of results, responding more on same trials than on different trials. These results are interpreted as being due to the interaction between the effects of occasion setting and negative priming (see Wagner, 1981). 相似文献
5.
C. H. Bennett V. L. Scahill D. P. Griffiths N. J. Mackintosh 《Learning & behavior》1999,27(3):333-345
Preexposure to two compound flavors (AX and BX) typically enhances their discriminability: An aversion conditioned to AX will generalize less to BX, especially if the preexposure regime has involved alternated presentations of AX and BX rather than presenting all AX trials before BX trials (or vice versa). One possible explanation of this finding is that alternating preexposure establishes inhibitory associations between the two unique features A and B, thus counteracting the generalization produced by excitatory associations between X and A and between X and B, which might result in either the retrieval of B on a conditioning trial to AX, or the retrieval of A on a test trial to BX. Three experiments on flavor aversion conditioning in rats tested these predictions. Experiment 1 suggested that the more important of these excitatory associations was that which allowed X to retrieve A on the test trial to BX. Experiment 2 suggested that the more important inhibitory association was that which allowed B to inhibit the representation of A on this test trial. Experiment 3 provided direct evidence of the role of this inhibitory B⊣A association. 相似文献
6.
Rats were exposed to three-trial series consisting of reinforced (R) trials and one nonreinforced (N) trial in a fixed order,
RRN and RNR (Experiments 1 and 2) or NRR and RRN (Experiment 3), on extended visually distinct runways in a T-maze. When initially
presented with the same sequence on each series in a session (separate presentations) with the same runway on all trials within
a series (Experiments 1 and 3), all the rats developed slower running speeds on N than on R trials. When a runway was sometimes
changed between the first and next two trials during separate presentations training (Experiment 2) or both sequences were
later intermixed within each session in each experiment, only rats exposed to each sequence on a specific runway maintained
these serial running patterns. Rats displayed serial running patterns on a test RNN sequence similar to that on the RNR sequence
(Experiment 2), as would be predicted by an intertrial association model of serial pattern learning (Capaldi & Molina, 1979),
but responded on test RRR and NRN sequences (Experiment 3) as would be predicted by an ordinal-trialtag/intratrial association
model (Burns, Wiley, & Payne, 1986). Results from test series of free-choice trials in Experiments 1 and 2 failed to support
a prediction of the intratrial association model that these rats would integrate RRN and RNR sequences. Rather than always
selecting a baited runway on both the second and the third free-choice trials, the rats only selected a baited runway on the
third trial on the basis of their choice on the second trial, as would be predicted by the intertrial association model. Only
after experiencing all possible outcome sequences during forced-choice training in Experiment 3 did these rats predominantly
select a baited runway on every free-choice trial. 相似文献
7.
Two fear-conditioning experiments with rats assessed whether retrospective revaluation, which has been observed in cue competition (i.e., when compounded cues are followed with an outcome), can also be observed in retroactive cue interference (i.e., when different cues are reinforced in separate phases with the same outcome). Experiment 1 found that after inducing retroactive cue interference (i.e., X-outcome followed by A-outcome), nonreinforced presentations of the interfering cue (A) decreases interference with responding to the target cue (X), just as has been observed in retrospective revaluation experiments in cue competition. Using the opposite manipulation (i.e., adding reinforced presentations of A), Experiment 2 demonstrated that after inducing retroactive cue interference, additional reinforced presentations of the interfering cue (A) increases interference with responding to the target cue (X); alternatively stated, the amount of interference increases with the amount of training with the interfering cue. Thus, both types of retrospective revaluation occur in retroactive cue competition. The results are discussed in terms of the possibility that similar associative mechanisms underlie cue competition and cue interference. 相似文献
8.
A variant of the taste aversion procedure for sensory preconditioning, as used by Rescorla and Cunningham (1978), was employed in a study of the context dependency of within-event learning. In two experiments, rats received Phase 1 exposure to a simultaneous flavor compound, AX; flavor X was paired with illness during Phase 2, and any tendency for the resulting aversion to be elicited by A was measured. It was found that subjects were less likely to shun flavor A as a consequence of this training if the Phase 1 and test episodes were conducted in distinctively different contexts. This effect was evident both when the change of context occurred just before the test with flavor A (Experiment 1) and when it occurred before Phase 2 (Experiment 2). These results were taken to imply that, as is often found with serial associations, the retrieval of within-event associations is subject to contextual control. The implications of these findings for the interpretation of perceptual learning effects are discussed. 相似文献
9.
We used an appetitive sensory preconditioning procedure to investigate temporal integration in rats in two experiments. In
Phase 1, rats were presented with simultaneous compound trials on which a 10-sec conditioned stimulus (CS) X was embedded
within a 60-sec CS A. In Group Early, CS X occurred during the early portion of CS A, whereas in Group Late, CS X occurred
during the latter portion of CS A. In Phase 2, CS X was paired simultaneously with sucrose. On a subsequent test with CS A,
the rate of magazine entries peaked during the early portions of the stimulus in Group Early and during the latter portions
of the stimulus in Group Late (Experiments 1 and 2). Similar response peaks were not observed on tests with a control stimulus
that had been presented in compound with a stimulus that did not signal reward (Experiment 2). 相似文献
10.
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
11.
In three experiments, the specificity of action of occasion setters was examined, using a discretetrial leverpress procedure. Rats’ acquisition of anXA+, A?, XB?, B+ discrimination, in which a single feature cue (X) signaled the reinforcement of responding in the presence of one target cue (A) and the nonreinforcement of responding during another target (B), was no more difficult than acquisition ofXA+, A?, X?, B+ orX+, A?, XB?, B+ discriminations, in whichX signaled only one target-response-reinforcement contingency. In transfer tests,X did not modulate responding controlled by other cues that were untrained or consistently reinforced, either when the elements of the compounds were presented serially or when they were presented simultaneously in training and testing. However, after serial, but not after simultaneous, compound training ,X facilitated responding controlled by a cue that was trained and then extinguished. Implications for the nature of occasion setting and configurai learning are discussed. 相似文献
12.
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
13.
Chad M. Ruprecht Joshua E. Wolf Nina I. Quintana Kenneth J. Leising 《Learning & behavior》2014,42(3):215-230
During feature-positive operant discriminations, a conditional cue, X, signals whether responses made during a second stimulus, A, are reinforced. Few studies have examined how landmarks, which can be trained to control the spatial distribution of responses during search tasks, might operate under conditional control. We trained college students to search for a target hidden on a computer monitor. Participants learned that responses to a hidden target location signaled by a landmark (e.g., A) would be reinforced only if the landmark was preceded by a colored background display (e.g., X). In Experiment 1, participants received feature-positive training (+←YB/ XA→+/A?/B?) with the hidden target to the right of A and to left of B. Responding during nonreinforced transfer test trials (XB?/YA?) indicated conditional control by the colored background, and spatial accuracy indicated a greater weighting of spatial information provided by the landmark than by the conditional cue. In Experiments 2a and 2b, the location of the target relative to landmark A was conditional on the colored background (+←YA/ XA→+/ ZB→+/ +←C /A?/B?). At test, conditional control and a greater weighting for the landmark’s spatial information were again found, but we also report evidence for spatial interference by the conditional stimulus. Overall, we found that hierarchical accounts best explain the observed differences in response magnitude, whereas spatial accuracy was best explained via spatial learning models that emphasize the reliability, stability, and proximity of landmarks to a target. 相似文献
14.
Three experiments examined inhibitory learning in rats, using Pavlovian and differential inhibitory eyeblink conditioning
procedures. Experiment 1 was designed to compare summation and retardation effects following Pavlovian conditioned inhibition
(A1/XA) or differential inhibition (A1/X) training using auditory and visual conditioned stimuli (CSs). After ten 100-trial
sessions of training, both Pavlovian conditioned inhibition and differential inhibition produced a retardation effect. However,
a summation effect was obtained only for rats given Pavlovian conditioned inhibition training. Experiment 2 showed that increasing
differential inhibition training to twenty 100-trial sessions produced summation and retardation effects. In Experiment 3,
rats were trained with either ten or twenty 100-trial sessions of intramodal inhibitory training with two tone CSs (2 kHz
vs. 8 kHz). Summation and retardation effects were obtained after only 20 sessions of differential conditioning. The findings
indicate that extensive training is needed to establish conditioned inhibition with intermodal or intramodal differential
conditioning. 相似文献
15.
The present study investigated the decrement in nutrient-based conditioned flavor preference found in hungry rats exposed
to a flavor following simultaneous flavor–sucrose conditioning while thirsty. Although a significant decrease in preference
was found in the experimental group in each experiment, there was no evidence of either spontaneous recovery (Experiment 1) or reinstatement (Experiment 2). In addition, posttraining flavor exposure weakened the original flavor–sucrose association (Experiment 3). These results suggested that the flavor–US association might have been impaired after posttraining flavor exposure. Two
further experiments assessed whether the flavor acquired the properties of a net inhibitor, using the retardation and summation
tests for conditioned inhibition. Experiment 4 revealed that the flavor suffered retardation when retraining was conducted after the exposure phase. In Experiment 5, the target flavor decreased the preference shown for a different flavor previously paired simultaneously with sucrose when
both were presented forming an unreinforced compound in the summation tests. None of these effects was found in a control
group, which had received serial flavor → nutrient presentations during training. Together, these results suggest that a flavor
simultaneously paired with sucrose acquires the properties of a net inhibitor when it is subsequently presented outside the
compound to hungry animals. 相似文献
16.
In Experiment 1, rats experienced presentations of a discrete visual stimulus (Stage 1) until habituation of the orienting response (OR) occurred. On a test session given after an interval of 16 days (Stage 2) the OR reappeared. For control subjects that received no Stage 1 training but presentations of the light in Stage 2, habituation persisted during the test. All subjects then received conditioning trials on which the light preceded the delivery of food. They showed latent inhibition, acquiring the conditioned response less readily than control subjects that had not previously experienced the light. Experiment 2 confirmed that the latent inhibition effect survived the retention interval for subjects that received no habituation test session. This pattern of results implies that habituation of the OR and latent inhibition are determined by different mechanisms. 相似文献
17.
Robert A. Rescorla 《Learning & behavior》1991,19(4):355-360
In two autoshaping experiments, pigeons received training of several modulators with each of two target excitors. Experiment 1 used a conditioned-facilitation (A?/XA+) procedure, and Experiment 2 used a conditioned-inhibition (A+/XA?) procedure. In the first procedure, the X modulators promoted responding to A, whereas in the second they depressed responding to A. Pairs of the X modulators were then presented in conjunction with a novel target stimulus, B. The ability of those pairs to modulate responding to B was greater when the modulators in a pair had both been trained with the same A stimulus rather than with different A stimuli. That suggests an involvement of the original training targets in the transfer of modulators to a novel target. 相似文献
18.
Retroactive cue interference refers to situations in which a target cue X is paired with an outcome in phase 1 and a nontarget cue Z is paired with the same outcome in phase 2, with less subsequent responding to X being seen as a result of the phase 2 training. Two conditioned suppression experiments with rats were conducted to determine whether retroactive cue interference is similarly modulated by a manipulation that influences retroactive outcome interference (e.g., extinction). Both experiments used an ABC renewal-like design in which phase 1 training, phase 2 training, and testing each occurred in different contexts. Experiment 1 found that training the target association in multiple contexts without altering the number of training trials during phase 1 decreased retroactive cue interference (i.e., increased responding consistent with the target association). Experiment 2 found that training the interfering association in multiple contexts without altering the number of interference trials during phase 2 increased retroactive cue interference (i.e., decreased responding consistent with the target association). The possibility of similar mechanisms underlying cue interference and outcome interference is discussed. 相似文献
19.
Three experiments investigated conditioning of the rabbit’s nictitating membrane response (NMR) in a second-order conditioning procedure which intermixed first-order trials (CS1-US) and second-order trials (CS2-CS1) from the outset of training. Experiment 1 provided a controlled demonstration that substantial levels of second-order conditioning can be obtained with the NMR preparation. Experiment 2 showed that the level of CR acquisition to CS2 was an inverse function of the CS2-CS1 interval over the values of 400, 800, and 2,400 msec. Experiment 3 found that CR acquisition to CS2 and CS1 in second-order conditioning varied in a parallel fashion across CS1-US intervals. Similarly, Experiment 3A found that the level of CR acquisition to the two components of a serial compound (CSA-CSB-US) varied in a parallel fashion as a function of the CSB-US interval. The results of the CS2-CS1 and CS1-US interval manipulations were all predictable from the known CS-US interval effects in NMR conditioning with a single CS. The present results are discussed with regard to their implications for accounts of serial compound conditioning and second-order conditioning. 相似文献
20.
It is generally agreed that the Kamin blocking effect provides a differential test of the model of classical conditioning proposed by Rescorla and Wagner (1972), on the one hand, and the models proposed by Mackintosh (1975) and Pearce and Hall (1980), on the other. Specifically, if the blocking effect occurs with 1 compound trial, Rescorla and Wagner are supported. Experiment 1 showed that prior training with one element of a simultaneous compound stimulus prevented the added element from becoming conditioned with 10 compound trials when compared with a nonpretrained (Kamin) control. A pseudoconditioning control, which received no compound training, showed substantial suppression only on the first trial. A contextual conditioning control, which received unsignaled shock prior to compound training, was suppressed, suggesting a failure of conditioning to contextual cues. Experiment 2 demonstrated 1-compound-trial blocking using a simultaneous presentation of the compound elements. The importance of this support for the Rescorla-Wagner model is discussed in the light of other supportive studies and those which support alternative models of classical conditioning. 相似文献