共查询到20条相似文献，搜索用时 421 毫秒
1.
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
2.
Frederick R. Maxwell Richard S. Calef D. W. Murray J. C. Shepard R. A. Norville 《Learning & behavior》1976,4(4):480-484
Multiple shifts in reward amount were given to rats in a straight runway. Both positive and negative contrast effects were observed. A positive contrast effect was observed, however, only if the shift from small to large reward occurred while the subject was evidencing a negative contrast effect. Implications for current conceptions of reinforcement contrast are discussed. 相似文献
3.
In four experiments, the once daily availability of saccharin (.15%) preceded the availability of sucrose (32% or 2%). Experiment 1 showed that the intake of saccharin was reduced when it preceded 32% sucrose but not when it preceded 2% sucrose, as compared with saccharin-alone conditions. Experiment 2 showed that less saccharin was consumed when the saccharin preceded sucrose by 5 min than when there was a 30-min intersolution interval. Experiment 3 replicated this finding and showed that the presentation of the two solutions through the same or different access holes in the apparatus was not relevant to the result. Experiment 4 showed that there was an inverse relationship between saccharin intake and the length of the intersolution interval in the range of 1 to 30 min. These data were interpreted to indicate that the animals learn the predictive relationship between the saccharin and sucrose solutions and that the intake of the saccharin is reduced by an anticipatory contrast mechanism—a mechanism that may have restricted temporal parameters. 相似文献
4.
Joan S. Rabin 《Learning & behavior》1975,3(4):290-294
The effect of quantity and quality of reinforcement on performance change following a shift to uniform high reward was studied in four groups of rats. Twenty or 200 licks of a 5% or 20% sucrose solution constituted the four incentive conditions. Two additional subject groups were run in the high (20%–200 licks) and low (5%-20 licks) reward conditions to determine how amobarbital sodium, an emotional depressant, influences incentive shift performance. All six groups received 60 preshift runway trials (6/day), followed by 30 high reward trials. Twenty-four extinction trials contrasted drugged and normal performance relating to high and low reward Postshift positive contrast appeared in all nondrugged groups. An emotional base for positive contrast is considered. 相似文献
5.
Contrast in consummatory behavior was investigated following repeated shifts from 32% to 4% sucrose. In Experiment 1, contrast in licking and in open-field measures of activity occurred following the second and third downshifts. In Experiments 2a and 2b, equivalent contrast effects occurred following the first and second downshifts in sucrose. In Experiment 3, negative contrast remained unabated following nine downshifts in animals shifted between 32% and 4% sucrose on alternate days. Similar results were found for five downshifts in animals shifted every 2 days. In both of these latter conditions, positive contrast occurred over the first few shifts and was then lost as the 32% control group reached asymptote. These data show that repeated negative contrast effects in consummatory behavior are robust and enduring and occur under several different sets of experimental parameters. The results are discussed in terms of reinforcement level and emotional interpretations of contrast effects, and the possibility was suggested that the causal mechanism of contrast changes with repeated shifts. 相似文献
6.
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
7.
In three experiments, the time horizon over which the rat evaluates alternative feeding sources was investigated. The time horizon was measured by the suppression of intake of one incentive (a 0.15% saccharin solution) when a preferred alternative incentive (a 32% sucrose solution) was available but delayed. In Experiment 1, we found a direct function between the amount of saccharin intake and the delay time before access to 32% sucrose. Compared with intake for a saccharin-only control, saccharin intake was suppressed before 4-min and 16-min sucrose delays, but not before a 32-min delay. Because previous work (Flaherty & Checke, 1982) had reported suppression before a delay of nearly 32 min, in the subsequent experiments we examined factors that might account for this difference. In Experiment 2, we found that saccharin intake was suppressed before a 32-min delay interval when saccharin and sucrose solutions were presented in a bright-novel test environment but not when the same solutions were presented in the home cage. In Experiment 3, we found that the time between testing and subsequent postsession feeding could also affect the suppression of saccharin intake. Saccharin intake was suppressed when access to 32% sucrose was delayed by 32 min and the test situation was followed by immediate postsession feeding, but not when postsession feeding was delayed by 90 min. These results thus extend estimates of the rat’s time horizon to at least 32 min, but indicate that the effective time horizon can vary, depending on the test situation. 相似文献
8.
Previous experiments have shown that the intake of a 0.15% saccharin solution is suppressed if saccharin access is followed by access to 32 % sucrose in brief daily pairings. The present experiments found that: (1) the degree of suppression was not altered when no time elapsed between presentation of the two solutions each day (15 sec had been the minimum in previous experiments and was used as the control in this experiment); (2) the degree of suppression was not altered by chlordiazepoxide (6, 12, or 20 mg/kg), although the drug had large appetite-stimulating effects; (3) suppression was not influenced by amphetamine (0.25 or 0.50 mg/kg); and (4) contrast could be established or eliminated, even after extended training, by manipulating the sequences of solutions presented (saccharin-saccharin or saccharin-sucrose). The results were interpreted in terms of a contrast effect based on the learned anticipation of a preferred substance. The chlordiazepoxide data suggest that this contrast is different from successive negative contrast, and the intersolution interval data suggest that the occurrence of contrast rather than a reinforcement effect is not due to a time gap between presentations of the two solutions. 相似文献
9.
Reactivity to a reward is affected by prior experience with the different reinforcer values of that reward, a phenomenon known as incentive relativity, which can be studied using the consummatory succesive negative contrast (cSNC) paradigm, in which the performance of animals that receive a 4 % sucrose solution after trials on which they were exposed to 32 % sucrose is compared with that of subjects that always receive the 4 % sucrose solution. The exploration of a novel open field can enhance or block the acquisition of associative and nonassociative memories. The effect of open field on cSNC has not yet been explored. The main result of the present study was that open-field exposure significantly modified the expression of cSNC. Exposure to an open field 1 h but not immediately before the downshift interfered with the expression of cSNC. These animals drank more of the downshifted reward than did controls that were not exposed to the apparatus, and this behavior persisted for up to three recovery trials. This phenomenon was observed even when the animals were given a more protracted preshift phase and when the discrepancy between the preshift and shift incentive values of sucrose were increased. An open field also interfered with incentive downshift when open-field exposure occurred 6 h before the downshift, and repeated exposure to the apparatus did not deteriorate this effect. The present study adds to a growing body of literature that indicates that open-field exploration can interfere with memory formation. 相似文献
10.
Modulation of taste-induced drinking: The effects of concentration shifts and drinking interruptions
The drinking of saccharin solutions by nondeprived rats was found to increase on initial exposure as a function of daily sessions and not as a function of previous state of deprivation or vigor of drinking. Large and persisting positive and negative successive contrast effects followed a single shift in concentration. Forcing the drinking to occur in short bouts by withdrawing the drinking tube elevated total intake above the level established by the positive and negative contrasts. The drinking returned to baseline when uninterrupted drinking was permitted. Maximum drinking occurred with 10- and 20-min interruptions of 2-min drinking periods. Consecutive daily interrupted drinking sessions did not produce further increases in drinking, as might have been predicted by opponent process theory or by a classical conditioning interpretation. It was suggested that the persistence of the positive and negative contrasts was dependent on the limited past experience of the animals with the saccharin taste, and that the enhancement of drinking by interruption may depend on the increased excitement produced by drinking tube withdrawal and the reduction of the excitement by reintroduction of the tube. 相似文献
11.
Contrast in consummatory behavior occurs readily when a less preferred substance follows a preferred substance. A previous experiment indicated that contrast in consummatory behavior may also develop when a less preferred substance precedes a preferred substance in brief daily exposures. In the present experiment, the same animals sometimes received 0.15% saccharin followed, 15 sec later, by 32% sucrose (.15–32) and sometimes received 0.15% saccharin followed by the same 0.15% saccharin solution (.15-.15). One solution pair was given each day, and the two conditions, .15–32 and .15-.15, occurred in alternation across days. The two different solution conditions were correlated with different cues. Saccharin intake from the first tube was lower when the second tube contained 32% sucrose than when it contained .15% saccharin, both in original discrimination training and following a reversal of the cue-solution pairings. These results support the conclusion that contrast in this situation is based on the anticipation of the impending 32% sucrose each day, rather than on a retrograde comparison with the 32% sucrose received the previous day. These data are considered in terms of Pavlovian conditioning outcomes when the CS is a stimulus with hedonic value. 相似文献
12.
Bruce R. Lombardi 《Learning & behavior》1980,8(4):617-620
In two experiments, a successive negative contrast effect in licking was produced by shifting rats from 32% to 4% sucrose solution. Subsequent to the downshift in reward, the rats were tested for licking either a plain 12% sucrose solution or 12% plus a neutral flavor. Licking for the 12% solution was depressed in downshifted rats when a flavor was present, regardless of whether this flavor was novel or had been present in the shift solution. The results were interpreted in terms of an enhancement of neophobia by reward reduction. 相似文献
13.
In a repeated shifts experiment four independent groups of thirsty rats received the following treatments: LSLS, LLLS, SSLS, and SSSS, with each letter denoting the magnitude (large or small) of sucrose reward received in each of the four phases of the experiment. While no negative contrast effect (NCE) was obtained in Phase 2, a very reliable positive contrast effect (PCE) was found in Phase 3. Moreover, a significant NCE was obtained in Phase 4. The results were explained in terms of the relative rather than absolute effects of reinforcement. 相似文献
14.
In three experiments, we studied the consequences of ejaculation upon the frustrative or contrast response of male rats exposed
to reward downshift situations (i.e., surprising changes from 32% to 4% sucrose solutions). Similar to what has been found
after treatment with anxiolytic agents, consummatory suppression was partially reversed by previous ejaculations in a second
postshift trial (Experiments 2 and 3), such a result not having been obtained in a first postshift trial (Experiment 1). Moreover,
the effect of ejaculations upon males' behavior during a second postshift trial was transitory, disappearing when assessed
during the third and fourth postshift trials (Experiment 3). These results are in accordance with both Amsel's (1958, 1992)
frustration theory and Flaherty's (1996) multistage hypothesis of successive negative contrast; the diverse factors that are
known to modulate contrast effects are considered, including an interpretation of the present data in terms of the anxiolytic-like
effect of the ejaculation. 相似文献
15.
Joseph M. Scandura 《Journal of Experimental Education》2013,81(4):12-18
Four behavior patterns exhibited by students in the classroom have been identified by the authors. These behavior patterns are defined as an active learning pattern, a passive learning pattern, a non-participative pattern, and a disruptive pattern. Each behavior pattern is a result of the matching or mismatching of a student’s affective and cognitive skills with the demands of the classroom environment. Each behavior pattern is characterized by three stages-tentative, testing, and patterned-where the student perceives the possibility of reward for a certain behavior, tests whether this reward can be produced on demand, and finally adopts a behavior pattern. The authors believe that shifts in behavior patterns are possible at each stage of development if appropriate changes are made in the classroom environment, but that each stage of each pattern has its own discrete shift and remedy. 相似文献
16.
In three experiments, the learning of flavor preferences due to pairing with calories was examined. In Experiment 1, the relative hedonic values of four isocaloric solutions and saccharin were assessed by offering these substances simultaneously to naive rats. The caloric solutions were then used to condition a flavor preference in separate groups of rats. Although the solutions were reliably different in unconditioned hedonic value, the conditioned flavor preferences were identical. In Experiment 2, we compared solutions of sucrose and saccharin that were equal in unconditioned hedonic value. Only the sucrose conditioned a preference. Finally, in Experiment 3, preferences were found to be sensitive to the number of calories available during conditioning. These results are discussed in terms of a peripheral cholecystokinin (CCK) reflex and the integration of that information along with taste information at the area postrema (AP) and surrounding nuclei. It is proposed that CCK acts centrally to adjust the incentive motivation or hedonic value of flavors. 相似文献
17.
In four experiments, food deprivation was varied during conditioning and testing of conditioning of flavor preferences by sweeteners. Conditioned preferences for a flavor associated with a more concentrated solution were enhanced by increased deprivation in training whether sucrose or saccharin was used when rats consumed solutions freely during training. When consumption of solutions was controlled and higher deprivation levels were used, preference for the higher concentration of sucrose was still enhanced by increased deprivation in training, but this did not occur with saccharin. We suggest that deprivation may enhance the reinforcing value of sweetness only when calories increase along with sweetness. We also suggest that deprivation can enhance flavor preference learning by increasing consumption and thereby increasing exposure to the flavored solutions. 相似文献
18.
Four groups of rats were given six acquisition trials under continuous reward, continuous delay of reward, partial reward, or partial delay of reward, following which all Ss received continuous delay. It was found that the partial reward and the partial delay of reward groups were significantly more persistent during the shift phase than the continuous reward group. No differences were found over trials between either the two partial groups or between each one and the continuous delay group. 相似文献
19.
In three experiments, rats shifted from 32% to 4% sucrose consumed less of the 4% sucrose than did rats that had received only the 4% solution. Experiment 1 showed that this negative contrast effect was not accompanied by a corticosterone elevation on the first day subsequent to the shift. Experiments 2 and 2a showed that corticosterone levels were substantially elevated on the 2nd postshift day and that there was a tendency for degree of elevation in corticosterone to be related to degree of lick suppression. These results are discussed in terms of other data suggesting that anxiolytic drugs and disinhibitory stimuli are more effective in alleviating contrast on the 2nd postshift day than on the 1st postshift day. It is suggested that, in the present paradigm, reaction to stimulus change may be the primary determinant of contrast on the 1st postshift day, but emotional processes related to reward loss and/or conflict develop by the 2nd postshift day. 相似文献
20.
Robert Lehr 《Learning & behavior》1974,2(3):221-224
In two experiments, groups of rats were given 50% or 100% of either a large (eight pellets) or small (one pellet) reward. All rats were then given 100% large reward. A 20-sec delay of reward was used throughout. Positive contrast effects were obtained in both experiments and schedule of reward did not interact with this effect. 相似文献