共查询到20条相似文献，搜索用时 15 毫秒
1.
Ruth M. Colwill 《Learning & behavior》2001,29(2):153-164
The effect of noncontingent outcomes on an instrumental response-outcome (R-O) association was examined in four experiments using transfer tests. In each experiment, rats were first given instrumental discrimination training designed to establish different stimuli as signals (S+s) for different outcomes. Transfer responses were subjected to different treatments across the experiments and then tested with the S+s. In Experiments 1 and 2, two transfer responses were both initially trained with two contingent outcomes. Then, each transfer response was subjected either to the addition of noncontingent presentations of one of those outcomes (Experiment 1) or to the replacement of one of the contingent outcomes with noncontingent presentations of that outcome (Experiment 2). Transfer tests revealed no significant difference in the ability of an S+ to promote performance of a transfer response based on their shared association with either the contingent or the noncontingent outcome. These results suggest that a response reinforced with two outcomes remains equally well associated with both of those outcomes despite prolonged exposure to noncontingent presentations of one of those outcomes. In Experiments 3 and 4, the possibility that the noncontingent schedules of reinforcement used in Experiments 1 and 2 might be capable of establishing an association between a response and its noncontingent outcome was examined. Transfer responses were trained with one contingent outcome and a different noncontingent outcome. Performance of these transfer responses was augmented more by presentations of an S+ trained with the contingent outcome than with the noncontingent outcome. These results confirm previous reports that instrumental responses are sensitive to outcome contingencies in acquisition and that noncontingent outcome presentations do not weaken previously established R-O associations. Several explanations are considered for the failure of subsequent noncontingent presentations of an outcome to reduce the strength of its association with the instrumental response. 相似文献
2.
We conducted three experiments to investigate the associative structure underlying the reinstatement of instrumental performance
after extinction. In each experiment, rats were initially rewarded on two responses with different outcomes. At test, both
responses were extinguished in order to assess the impact of a single noncontingent outcome delivery on response selection.
Experiment 1 found evidence of outcome-selective reinstatement (i.e., more responses were performed on the lever that was
trained with the reinstating outcome than on the other lever). Experiment 2 demonstrated that the outcome’s capacity to reinstate
performance was not affected by a reduction in its motivational value. Experiment 3 found evidence that the reinstating outcome
selectively retrieved the response it signaled rather than the response it followed during training. Together, these findings
are consistent with the view that instrumental reinstatement depends on the discriminative stimulus properties of the reinstating
outcome. 相似文献
3.
To demonstrate a facilitating stimulus effect, as opposed to an incentive effect, of food reward, rats were trained on an easy, light-dark discrimination with different amounts of reward for correct and incorrect responses (1-0, 2-0, 3-1, and 5-1 pellets, respectively), and with shock or no shock administered in the correct goalbox. Both errors and trials to criterion were fewer with a large reward differential (LRD: 2-0 and 5-1), as compared with a small reward differential (SRD: 1-0 and 3-1), but were not affected by the “base” reinforcement condition of either 1 or 0 pellets for the incorrect response. In addition, choice and arm speeds during early training were positively related to the combined, or average, number of pellets contingent upon both correct and incorrect responses, indicating a generalization of reward expectancies. Although shock uniformly suppressed arm speeds under all reward conditions, it facilitated discrimination learning in the SRD conditions. That such facilitation occurred only when the conditions of reward for correct and incorrect responses were relatively similar indicates that not only shock, but also food can function as a distinctive cue: As a stimulus selectively applied to one response, it can decrease the similarity of the alternatives, and, in this manner, it can faciltate performance. 相似文献
4.
Angelo Santi 《Learning & behavior》1989,17(3):349-354
Pigeons were trained in a two-choice delayed matching-to-sample task with red and green hues. A brief postsample cue (a vertical or horizontal line) signaled whether the comparison stimuli would be presented or omitted on each trial. Comparison stimuli were always presented following the remember (R) cue, but never following the forget (F) cue or no-cue trials. One group of birds, the differential outcome (DO) group, received reinforcement with a probability of 1.0 for correct responses following one sample stimulus and a probability of 0.2 for correct responses following the other sample stimulus. The nondifferential outcome (NDO) group received reinforcement with a probability of 0.6 for correct responses to either stimulus. The effect of postsample cues was greater for the DO group than for the NDO group. Relative to the NDO group, the DO group displayed higher accuracy on R-cue trials and lower accuracy on F- and no-cue trials. Both tendencies contributed to the enhanced cue effectiveness obtained in the DO group. The results indicate that outcome expectancies are subject to maintenance rehearsal, which comes under the control of postsample R and F cues. They also suggest that maintenance rehearsal may be easier to sustain under DO conditions than under NDO conditions when a memory test is anticipated, but that it may be easier to terminate maintenance rehearsal under DO conditions when a memory test is not anticipated. The results are inconsistent with the assumption that the rehearsal of outcome expectancies is automatic. 相似文献
5.
The present work introduced a task which superimposed a tray brightness, stimulus-response contingency on previously acquired, highly successful, one-trial oddity performance. Continuing with new one-trial oddity problems, the new contingency was that responses to the odd objects were rewarded on a white tray and responses to the nonodd objects were rewarded on the black tray. Since there is no opportunity to learn specific stimuli or stimulus patterns, successful performance may be interpreted as having a conceptual basis. All monkeys achieved criterion (90% based on 18/20) and statistically significant performances (p<.001). Discussion considered the appropriate nomenclature to describe a conceptual conditional discrimination task and the necessary evidence to justify a conceptual interpretation of conditional discrimination behavior. 相似文献
6.
Three experiments, using rats, demonstrated the encoding of a food unconditioned stimulus (US) in a simple Pavlovian conditioning paradigm. In all three studies, one stimulus was used to signal the delivery of pellets and a different stimulus was used to signal the delivery of sucrose. In Experiment 1, postconditioning devaluation of one of the food USs selectively reduced the frequency of conditioned magazine-directed behavior during the stimulus trained with that US. In Experiment 2, transfer of the stimuli to instrumental responses resulted in selective depression of the response trained with a different outcome. In Experiment 3, acquisition of stimulus-outcome learning was impaired by unsignaled intertrial presentations of the same outcome but not of a different outcome. These results indicate that a detailed representation of the outcome is encoded in the normal course of Pavlovian conditioning. 相似文献
7.
The effect of stimulus rotation was assessed in four Guinea baboons (Papio papio), using pictures of familiar human faces presented in a computerized go/no-go task. In Experiment 1, 2 baboons were initially trained to discriminate upright faces, and 2 others were trained to discriminate upside-down faces. For the two groups, postlearning discrimination was impaired when the training faces were rotated 180°. In Experiment 2, upright and upside-down priming faces appeared prior to the display of target faces. For the two groups, response times were faster when the prime and the target faces had the same orientations than when they were depicted under different orientations. Finally, Experiments 3 and 4 identified variations in facial contours as the most salient discriminative cue controlling performance in 2 baboons. Altogether, our results provide no evidence that the baboons processed the pictures as representations of faces. It is suggested that the effect of rotation derived from the encoding of the pictorial faces as meaningless mono-oriented shapes, rather than as natural human faces. 相似文献
8.
Four experiments examined the influence of a stimulus presented after one response in a two-lever choice task. In Experiment 1, food-deprived rats trained on a concurrent variable-interval extinction schedule responded more often on the extinction lever when such responding periodically produced a visual stimulus than when it did not. In Experiments 2 and 3, a similar signal-induced enhancement effect was found even when food was delivered randomly with respect to responding on both levers or when no food was presented. In Experiment 4, a response-contingent visual stimulus elevated responding to the lever on which it was presented, but an auditory cue suppressed responding. These findings indicate that visual stimuli may possess intrinsically reinforcing properties for rats. 相似文献
9.
Acquisition, extinction, and transfer of facilitation were explored in a series of experiments with C57BL/6J mice. With a
procedure in which an auditory target was followed by food only in the presence of a visual facilitator, Experiments 1—4 showed
that the facilitator promoted magazine entries to the auditory target. This enhancement effect was eliminated by training
the facilitator as a conditioned inhibitor (Experiments 1 and 3B). Enhancement was also reduced by nonreinforced presentations
of the facilitator in a discrimination procedure (Experiment 1) and by simple nonreinforcement of the facilitator (Experiments
2, 3A, and 4). In contrast to the results obtained with a facilitator, simple nonreinforcement of an inhibitor, a visual cue
that had signaled when an auditory target would not be reinforced, did not reduce its ability to modulate responding to that
target (Experiment 4). However, both the facilitator and the inhibitor were found to transfer their modulatory effects to
other targets (Experiment 4). Finally, mice demonstrated no evidence of differential responding on a biconditional discrimination
procedure in which one auditory target (A1) was reinforced in the presence of one visual stimulus (L1) but not in the presence
of another (L2), and a different auditory target (A2) was reinforced in L2 but not in L1 (Experiment 5). The implications
of these results for analysis of the function of a facilitator are discussed. 相似文献
10.
Robert A. Rescorla 《Learning & behavior》1992,20(3):223-232
In three experiments with rats as subjects, instrumental training procedures were used to study the format of encoding of the reinforcing outcome (O). At issue is the relative contribution of response-outcome (R-O) associations between responses and their earned outcomes and of O-R associations between anticipated outcomes and responses reiaforced in their presence. In Experiments 1 and 2, R earned one O during a stimulus that controlled the anticipation of another O. Devaluation and transfer tests suggested that the earned O was more critical than the anticipated O in controlling behavior. In Experiment 3, a differential-outcomes procedure was used, with consistent R-0 relations arranged in groups that differed in the consistency of O-R relations. Subsequent devaluation of O produced similar selective depression of R, regardless of the O-R relations. These results suggest that an R-O association can contribute to instrumental performance more than does an O-R association. 相似文献
11.
Four experiments examined transfer of differential outcome performances to new choice responses in pigeons. Experiments 1A and 1B showed that new responses trained off a matching-to-sample baseline readily substituted for the choice alternatives in differential outcome matching, provided that they shared the same outcome associations as the alternatives they replaced. Experiment 2 showed that comparison responses trained on baseline, but in a task in which their different outcomes occurred equally often following each sample (viz., one-to-many matching), substituted for the choices in a standard, differential outcome task. Experiment 3 showed, somewhat surprisingly, that the choices in the latter task were likewise effective substitutes in one-to-many matching. These results pose separate challenges for standard two-process theory and for the bidirectional account of differential outcome performance, and they suggest other cues that pigeons may use to predict outcomes. 相似文献
12.
Ruth M. Colwill 《Learning & behavior》1991,19(4):326-336
Three experiments using rats examined whether a signal for the nonreinforcement of an instrumental response (S-) provided information about the identity of the omitted outcome. In all three experiments, one stimulus was established as a signal for the nonreinforcement of a response that earned food pellets and another stimulus signaled the nonreinforcement of a response that earned liquid sucrose. Experiment 1 found that each S-suppressed another instrumental response trained with the same outcome significantly more than a response trained with a different outcome. Using a variant of this transfer design, Experiment 2 demonstrated that an S- was slower to develop discriminative control over a new response reinforced in its presence with the same outcome compared with an outcome different from the one whose omission-the S- had previously signaled. Experiment 3 examined transfer of the S- stimuli to a response trained with two outcomes, one of which had subsequently been devalued. Performance of this response significantly increased in the presence of a signal for the omission of the devalued outcome, but decreased in the presence of a signal for the omission of the valued outcome. These results suggest that S-s do provide information about the identity of omitted response-contingent outcomes. 相似文献
13.
Working memory in a bottlenosed dolphin was tested in both indirect and direct auditory delayed-discrimination tasks in which a correct spatial response was conditional upon the nature of a preceding sound. In the indirect task, either one of two possible sounds was briefly presented. After a prescribed delay, the dolphin was cued to go either to a left-hand or right-hand paddle pair. Responses to the outer paddle of a pair were rewarded following sound A, and responses to the inner paddle of a pair were rewarded after sound B. In the direct delayed-discrimination task, only one paddle pair was used in each session. In both tasks, the delay interval between the discriminative sound stimulus and the opportunity for a spatial response was progressively increased over sessions until the animal failed to meet a specified performance criterion or self-terminated a session. Delay limits of about 30 and 60 sec were obtained in the indirect and direct tasks, respectively. The increase in delay limit in the latter task was attributable to the use of an overt mediational response during the longer delays. In both cases, however, the obtained delay limits fell considerably short of the 2- to 3-min limits obtained in auditory delayed-matching studies using the same test sounds and the same subject. The task differences indicate that working memory functions cannot depend upon memory of the predelay stimulus alone, but must be determined in part by additional processes. 相似文献
14.
Four experiments were conducted to explore outcome-specific transfer from causal predictive judgments to instrumental responding. A video game was designed in which participants had to defend Andalusia from navy and air force attacks. First, they learned the relationship between two instrumental responses (two keys on a standard keyboard) and two different outcomes (destruction of the ships or destruction of the planes). Then they learned to predict which of two different stimuli predicted which outcome. Finally, they had the opportunity of making either of the two instrumental responses in the presence of either stimulus. Transfer was shown as a preference for the response that shared an outcome with the current stimulus. The presentation of the stimulus during the test produced a decrease in the overall rate of response. Responding to a neutral stimulus in Experiments 2 and 3 suggested that this overall decrease in responding was due to a combination of the time needed to process the meaning of the stimulus and the activation of the representation of the outcome in the presence of the stimulus during the test. Transfer between predictive judgments and instrumental responding mirrors the outcome-specific Pavlovian instrumental transfer observed in conditioning studies with rats. 相似文献
15.
Robert A. Rescorla 《Learning & behavior》1990,18(2):206-211
In three experiments, thirsty rats were trained to make several instrumental responses whose outcomes differed in which of two relatively inconsequential flavor features they contained. In Experiment 1, one of the features was subsequently devalued by pairing it with lithium chloride; in Experiment 2, it was enhanced in value by pairing it with sucrose. In both experiments, differences in the value of the features resulted in parallel differences in the likelihood of the responses during a subsequent extinction test. In Experiment 3, the animals chose between these responses in the presence of discriminative stimuli that had signaled the occurrence of these different features following another response. The stimuli selectively augmented the likelihood of the response with which they shared training by the same-flavored consequence. These results indicate that rats can separately encode features that differ along one dimension, both in the association between an instrumental response and its outcome, and in the association between a discriminative stimulus and that outcome. 相似文献
16.
Four number-trained rhesus monkeys were trained to enumerate their sequential responses. After completing a series of computerized
maze trials, the monkeys were given a same/different discrimination involving a numerical stimulus (an Arabic numeral or a
visual quantity) and the letterD. The goal was to choose the numerical stimulus if it matched the number of just-completed maze trials, and to choose the
letterD if it did not. There were large individual differences in performance, but one animal performed above 70% when receiving
randomly intermixed series of 1, 3, 5, and 9 maze trials. This indicates that the monkey was keeping track of the approximate
number of maze trials completed in each series and using that numerical cue to respond during the same/different discrimination. 相似文献
17.
Five rhesus monkeys were tested across a series of object discrimination problems requiring avoidance of noxious pressurized air. Each S displayed a progressive reduction in the number of trials to reach criterion on particular problems, eventually achieving 82% and 88% correct performance on Trials 2–6 and Trial 6. respectively. Certain error factors also appearing in appetitive discrimination learning set research (stimulus perseveration and differential cue) were identified, as well as a factor of relative unimportance in appetitive set (positional responding). A most persistent appetitive error factor presumably reflecting a tendency to explore the unchosen object (response shift) did not appear. In addition, the results extend the effectiveness of aversive airblasts to a relatively complex discrimination task. 相似文献
18.
In three experiments the sensitivity of instrumental responding to revaluation of the instrumental outcome in the absence of experience with the revalued outcome was examined. Hungry rats were trained to make one response for food pellets and a different response for sucrose liquid. In Experiment 1, these responses were tested in extinction when the animals were either thirsty or hungry. A significant preference for the sucrose-trained response was observed in the test conducted under thirst but not in that conducted under hunger. In Experiments 2 and 3, the effect of experience with sucrose under thirst on the magnitude of this preference was explored. Following training of the instrumental responses in Experiment 2, half of the animals received presentations of sucrose while they were thirsty; the other half received sucrose while they were hungry. In Experiment 3, the same design was used but these sucrose presentations were made contingent on an instrumental response. Also in Experiment 3, the specificity of the sucrose-response preference to a shift to thirst was examined by testing under increased and decreased levels of hunger. The results of those experiments indicated that the sucrose-response preference is exhibited only under thirst and that exposure to the sucrose under thirst only marginally enhanced that preference. These findings suggest that instrumental responding may be modified by changes in the value of its outcome in the absence of experience with the revalued outcome. 相似文献
19.
Midsession reversals with pigeons: visual versus spatial discriminations and the intertrial interval
Jennifer R. Laude Jessica P. Stagner Rebecca Rayburn-Reeves Thomas R. Zentall 《Learning & behavior》2014,42(1):40-46
Discrimination reversal learning has been used as a measure of species flexibility in dealing with changes in reinforcement contingency. In the simultaneous-discrimination, midsession-reversal task, one stimulus (S1) is correct for the first half of the session, and the other stimulus (S2) is correct for the second half. After training, pigeons show a curious pattern of choices: They begin to respond to S2 well before the reversal point (i.e., they make anticipatory errors), and they continue to respond to S1 well after the reversal (i.e., they make perseverative errors). That is, pigeons appear to be using the passage of time or the number of trials into the session as a cue to reverse, and are less sensitive to the feedback at the point of reversal. To determine whether the nature of the discrimination or a failure of memory for the stimulus chosen on the preceding trial contributed to the pigeons’ less-than-optimal performance, we manipulated the nature of the discrimination (spatial or visual) and the duration of the intertrial interval (5.0 or 1.5 s), in order to determine the conditions under which pigeons would show efficient reversal learning. The major finding was that only when the discrimination was spatial and the intertrial interval was short did the pigeons perform optimally. 相似文献
20.
Dave G. Mumby Tom J. Kornecook Emma R. Wood John P. J. Pinel 《Learning & behavior》1995,23(4):447-453
Two experiments assessed whether odors left on stimulus objects by experimenters who handle them might confound the interpretation of ostensibly visually guided object-memory tasks for rats. In Experiment 1, rats were able to discriminate the relative recency with which an experimenter touched two otherwise identical objects (intertouch interval = 4 sec), presumably on the basis of an odorintensity discrimination. However, after the rats mastered the odor discrimination with no delay between when the second of the two stimulus objects was last touched by the experimenter and when the rats were permitted to attempt the discrimination, their performance dropped to chance levels when this delay was increased to 15 sec. In Experiment 2, rats were trained in two slightly different ways to perform a delayed-nonmatching-to-sample (DNMS) task, one that involved systematic differences in the temporal order in which the experimenter handled the sample and novel stimulus objects and one that did not. There were no significant differences in the rate at which rats mastered the DNMS task with these two procedures, and the performance of rats that were trained according to the former procedure was unaffected when they were switched to the latter procedure. Moreover, rats required considerably fewer trials to master the DNMS task than the rats in Experiment 1 required to master the odor discrimination. These findings demonstrate that, under certain circumstances, rats can discriminate the relative recency with which two objects are handled by an experimenter, but that this ability contributes little to their performance of conventional object-based DNMS tasks. 相似文献