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1.
Deprivation shifts, using conditions analogous to those which produce strong incentive contrast when reward quantity is changed (extended preshift training, short interval from the last preshift trial to the first postshift trial, large preshift differences in deprivation) resulted in contrast of runway speed and choice behavior. In the first experiment, a downshift of hunger during rats’ runway training produced a slow lessening of speed below that of a group trained continually at low hunger. In the second experiment, rats were trained to traverse a runway to one food-containing goalbox when very hungry and to another, distinctively different food-containing goalbox when not very hungry. The rats were next given a series of choice trials between the two goalboxes. There was a brief preference for the high-hunger goalbox, followed by a preference for the low-hunger goalbox. The results of the second experiment suggest that deprivation affects the strength of conditioning of a cue-reinforcer expectancy, while the slow development of contrast in the first experiment indicates that deprivation also affects the development of either habit strength or a response-reinforcer expectancy. 相似文献
2.
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
3.
This study further investigates the relationship between cage size and activity in the open field. Male hooded rats were housed at weaning either individually or in pairs in small, medium, or large cages and observed after 15 days in an apparatus providing a choice between three environments of identical construction and dimensions to the different home cages. Three experimental conditions were employed. Both isolated and pair-housed rats were tested alone in the unfamiliar apparatus and some isolated rats were first habituated to the apparatus. Time spent in each size apparatus component was recorded. The results failed to explain earlier findings of a positive relationship between open-field behavior and cage size in isolated rats, in terms of spatial preference. Isolated component preferences were inversely related to cage size, while pair-housed preferences were positively related to cage size. Component preference was not related to component area or perimeter distance. The implications of this spatial behavior for exploration and emotionality theories are discussed. 相似文献
4.
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
5.
Male and female Long-Evans rats were given open-field tests at 30 and/or 120 days of age. At 30 days of age, males and females did not differ in their open-field behavior. At 120 days of age, however, females locomoted more, reared more, and showed less wall-hugging than males, regardless of whether or not the animals had received tests in the open field at 30 days of age. The appearance of sex differences was due to an increase in the scores of the females between 30 and 120 days of age. 相似文献
6.
Charles F. Flaherty 《Learning & behavior》1982,10(4):409-440
The literature relevant to incentive contrast effects is reviewed, with emphasis on the data published since the reviews by Black (1968) and Dunham (1968). Contrary to the evidence available for the earlier reviews, the current literature indicates that positive contrast is a reliable phenomenon. Its occurrence is facilitated by use of a constant delay of reward, use of a long runway, or possibly by a shift while a negative contrast effect, resulting from a previous shift, is still present in the animals’ behavior. Positive contrast also occurs in consummatory behavior when sucrose or saccharin solutions are shifted. Conditions that are ineffective in producing positive contrast are reviewed, as are the effects of numerous variables on both successive and simultaneous contrast. In addition, positive and negative contrast effects resulting from shifts in delay or percentage of reward, contrast resulting from shifts in sucrose, saccharin, or ethanol solutions, contrast in choice behavior, and transsituational contrast are reviewed. The relationship of the data to several theoretical interpretations of contrast is also considered. 相似文献
7.
We previously reported that chimpanzees were unable to optimally select the smaller of two candy arrays in order to receive a larger reward. When Arabic numerals were substituted for the candy arrays, animals who had had prior training with numerical symbols showed an immediate and significant improvement in performance and were able to select reliably the smaller numeric representation in order to obtain a larger reward. Poor performance with candy arrays was interpreted as reflecting a response bias toward the intrinsic incentive and/or perceptual features of the larger array. In contrast, the Arabic numerals represent numerosity symbolically and appear to promote response choice on the basis of abstract processing of numerosity, with minimal interference from the inherent properties of the choice stimuli. The present study tested the hypothesis that, for mixed symbol-candy choice pairs, the requisite processing of the abstract numeral may foster a mode of numerical judgment that diminishes the interfering incentive/perceptual effects of the candy stimuli. The results were consistent with this hypothesis. Whereas performance on candy-candy arrays was significantly below chance levels, performance on numeral-candy choice pairs was significantly above chance and comparable with performance on numeral-numeral pairs. 相似文献
8.
An animal’s appetitive behavior is not a fixed response to current stimulation but can be affected by the anticipation of future events. For example, rats regularly given access to a moderately valued solution followed by a higher value solution (e.g., 4 % sucrose → 32 % sucrose) consume less of the initial solution than in control conditions where the initial solution is not followed by a higher value solution (e.g., 4 % sucrose → 4 % sucrose). Previous analyses have suggested that this negative anticipatory contrast effect does not depend on the “expectation” of a valuable stimulus producing a functional devaluation of a currently available stimulus of lesser value. In a within-subjects anticipatory contrast procedure, this study revealed that both consumption and the mean size of licking clusters were smaller for a 4 % sucrose solution on days when it preceded 32 % sucrose than on days when 4 % preceded 4 %. Since lick cluster size typically bears a positive monotonic relationship with the concentration of palatable solutions, this reduction is indicative of a decrease in the palatability/hedonic value of the solution subject to contrast. As such, we provide direct evidence that negative anticipatory contrast does produce a functional devaluation of the solution, thus challenging prevailing theoretical assumptions. 相似文献
9.
Previous work has shown that when a delay of reward (DOR) is introduced into a well-learned discrimination, even gradually, discriminative performance deteriorates and, with moderately long DORs, does not recover with practice. The present experiment assessed whether the decrement in performance was due to an associative loss or to a decline in the incentive value of the reward object caused by the DOR. Cebus monkeys were trained on a simple visual discrimination and tested with either a DOR or an identical delay period which preceded the appearance of S+ and S? (“predelay” trials); reinforcement on predelay trials was immediate. On half of the daily trials, the animals were given the option of choosing either the DOR or the predelay trial. The duration of the delay was increased gradually until terminal delays of 32 to 128 sec were reached. All four animals maintained almost errorless performance on predelay trials; in contrast, their error rate reached 36% on DOR trials. Surprisingly, none of the animals learned to choose predelay over DOR trials. Both results were interpreted in terms of the incentive loss hypothesis. 相似文献
10.
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
11.
Based on a model which holds that open-field behavior is due in large part to an interaction between social separation and the threat of predation, seven experiments were conducted to examine the relationship between tonic immobility and open-field activity in chickens. The results showed that placement in an open field prior to testing for tonic immobility reliably enhanced the duration of immobility. Similarly, procedures that have been shown to modify the length of the immobility episode had a comparable effect on the timing of activity onset in an open field. Since tonic immobility has been independently implicated as a putative predator defense, the correspondence between open-field behavior and tonic immobility was taken as indirect support for the hypothesis that open-field testing contains overtones of predation. 相似文献
12.
Luís Gonzalo De la Casa Auxiliadora Mena Juán Carlos Ruiz-Salas Esperanza Quintero Mauricio R. Papini 《Learning & behavior》2018,46(1):49-59
Three experiments explored the link between reward shifts and latent inhibition (LI). Using consummatory procedures, rewards were either downshifted from 32% to 4% sucrose (Experiments 1–2), or upshifted from 4% to 32% sucrose (Experiment 3). In both cases, appropriate unshifted controls were also included. LI was implemented in terms of fear conditioning involving a single tone-shock pairing after extensive tone-only preexposure. Nonpreexposed controls were also included. Experiment 1 demonstrated a typical LI effect (i.e., disruption of fear conditioning after preexposure to the tone) in animals previously exposed only to 4% sucrose. However, the LI effect was eliminated by preexposure to a 32%-to-4% sucrose devaluation. Experiment 2 replicated this effect when the LI protocol was administered immediately after the reward devaluation event. However, LI was restored when preexposure was administered after a 60-min retention interval. Finally, Experiment 3 showed that a reward upshift did not affect LI. These results point to a significant role of negative emotion related to reward devaluation in the enhancement of stimulus processing despite extensive nonreinforced preexposure experience. 相似文献
13.
In previous experiments with individual honeybees that visited the laboratory regularly to take sucrose solution from a target set on the shelf of an open window, the overlearning-extinction effect was found for high concentrations of sucrose but not for low. The purpose of the present experiment was to examine the possibility that declining resistance to extinction in the course of prolonged training with a high concentration of sucrose could be explained in terms of increasing nutritive level. Three groups of animals were extinguished on a distinctive target, one group after 6 visits to the target, a second after 18 visits to the target, and a third after 6 visits to the target that were interspersed among 12 visits to a different target. More rapid extinction in the second group than in the third, which had fewer training visits to the extinction target than the second but the same total number of training visits, rules out an explanation in terms of nutritive level and points instead to a frustration-like process evidenced also in earlier work on incentive contrast. 相似文献
14.
Foraging honeybees were trained individually with successively presented targets differing in color, one containing 5 µl and the other 20 µl of 50% sucrose solution, after which preferences were measured in unrewarded choice tests. The targets were conical, designed to control for the possibility of differential delay of reward stemming from the greater detectability of the larger as compared with the smaller drops of sucrose when the drops were presented on the conventional flat targets. The new results for color, like recent results for odor, can be understood on the assumption that the attractiveness of a stimulus increases as a function of the strength of its association with reward and that the effect of amount of reward is on asymptotic strength. 相似文献
15.
In Experiment I, rats which were both hungry and thirsty were given a choice between a food reward and a water reward. The animals preferred food to water when the reward was delivered immediately, but preferred water to food when a 30-sec delay was imposed in the goalbox before the reward was received. Experiment II replicated the results of the first experiment and showed, in addition, that when the delay was imposed in a separate delay chamber devoid of differential goalbox cues, subjects preferred food to water, similar to the immediate group. The results were discussed in terms of an incentive value process and a competing response hypothesis. 相似文献
16.
John Archer 《Learning & behavior》1974,2(1):43-48
Sex differences in the emotional behavior of three strains of rats were investigated, using a variety of measures taken during the initial 2 min of open-field exposure and after a loud bell had sounded. Animals were tested either in a clean open field or in one containing the odor of a same-sex conspecific. No general overall sex differences for a variety of measures associated with emotional reactivity were found, so the results did not support the theory that male rats are more “emotional” than females. Sex differences for particular measures associated with emotional responsiveness were found, but these varied with the strain, measure, and odor condition: The latter was found to be particularly important. 相似文献
17.
The role of incentive learning in instrumental performance following a shift in the degree of water deprivation was analyzed in three experiments. In Experiments 1A and IB, rats trained to perform an instrumental action reinforced with either sucrose or maltodextrin solutions when in a high-deprivation state were subsequently shifted to a low-deprivation state and tested in extinction. This within-state shift in water deprivation reduced instrumental performance only when the animals had been exposed to the reinforcer in the low-deprivation state prior to instrumental training. In Experiment 2, a concurrent training procedure was used to assess whether the change in the value of the reinforcer brought about by preexposurewas mediated by the contingency between the instrumental action and the reinforcer. Preexposure to the reinforcer under the low-deprivation state produced a selective reduction of the performance of the action upon which it was contingent during training when testing was conducted in extinction following a shift from the high- to the low-deprivation state. These experiments provide evidence that animals have to learn about the incentive value of a reinforcer in a particular motivational state through exposure to the reinforcer in that state. 相似文献
18.
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
19.
P. A. Russell 《Learning & behavior》1977,5(3):297-302
Stationary visual scanning and sniffing of novel stimuli were measured using a head-poke response to supplement existing equivocal data on sex differences in exploration. With a short exposure to a novel apparatus, males and females showed a similar frequency of exploratory bouts, but the bouts were longer in females, showing that the sex difference is independent of a simple activity difference. With longer exposure, the difference was reversed, with males “compensating” for their initially lower level. Following familiarization to the apparatus, the sexes did not differ in exploration of an introduced novel stimulus. These results are consistent with males being more susceptible to inhibitory influences, such as disturbance and extreme novelty. Differences in within-trial changes in the level of exploration of a novel stimulus in novel and familiar environments were also observed. 相似文献
20.
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