共查询到20条相似文献，搜索用时 187 毫秒
1.
Dominic M. Dwyer Hannah L. Pincham Thida Thein Justin A. Harris 《Learning & behavior》2009,37(4):305-310
Learned flavor preferences can be strikingly persistent in the face of behavioral extinction. Harris, Shand, Carroll, and
Westbrook (2004) suggested that this persistence may be due to flavor preference conditioning’s producing a long-lasting change
in the hedonic response to the conditioned stimulus (CS+) flavor. In the present study, the CS+ flavor was presented in simultaneous
compound with 16% sucrose, whereas the CS− flavor was presented with 2% sucrose. During subsequent two- and one-bottle tests,
the CS+ and CS− flavors were presented in 2% sucrose. Hedonic reactions during training and test were assessed using an analysis
of the microstructure of licking behavior. Conditioning resulted in greater consumption of the CS+ than of the CS− that did
not extinguish over repeated two- and one-bottle tests. The mean lick cluster size was higher for the CS+ than for the CS−
only on the first cycle of tests. Since lick cluster size can be used as an index of stimulus palatability, the present results
indicate that although the hedonic reaction to the CSs did change, this was not maintained across repeated tests. Thus, changes
in the hedonic response to the conditioned flavors cannot explain the resistance to the extinction of learned flavor preferences. 相似文献
2.
Dwyer DM 《Learning & behavior》2008,36(2):149-158
The microstructure of licking responses was analyzed to investigate the interaction between unconditioned responses to maltodextrin and the responses to flavor cues previously associated with maltodextrin. Experiment 1 demonstrated that although the consumption of maltodextrin peaked at intermediate concentrations, the mean lick cluster size showed a positive, monotonic increase with concentration. In Experiment 2, a (conditioned stimulus) CS+ flavor was paired with 16% maltodextrin, whereas a CS- flavor was paired with 2% maltodextrin. During test, consumption of the CS+ was higher than that of the CS- when the flavors were combined with 2% maltodextrin, but not when combined with 16% maltodextrin. In contrast, cluster size was larger with the CS+ than with the CS-, regardless of the concentration of maltodextrin present on test. Previous analyses of licking microstructure indicate that cluster size reflects the palatability of the ingested solution. Thus, the present results indicate that flavor conditioning can change the palatability of the cue flavors. Adding the CS+ flavor to maltodextrin produced results analogous to increasing the concentration of maltodextrin (in terms of both consumption and licking microstructure measures), which is consistent with the idea that after conditioning, responses to the CS+ flavor and to the unconditioned stimulus are mediated via the same representation. 相似文献
3.
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
4.
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
5.
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
6.
Delamater AR 《Learning & behavior》2011,39(3):259-270
Two experiments with thirsty rats explored the harmful effects of non-reinforced exposures to a flavor cue in the control
by sensory-specific flavor–sucrose associations in a conditioned flavor preference paradigm. Experiment 1 demonstrated that rats learned to prefer a flavor cue that was consistently paired with sucrose over one that was paired
with sucrose the same number of times but was also presented without sucrose on other occasions. However, rats for which sucrose
was devalued following the conditioning phase preferred the partially reinforced flavor cue over the consistently reinforced
flavor, suggesting that non-reinforcement weakened the ability of that flavor cue to evoke a specific representation of sucrose
during the preference test. Experiment 2 demonstrated comparable effects of non-reinforcement in a latent inhibition procedure, although relatively more non-reinforced
pre exposures to the flavor, in conjunction with fewer flavor–sucrose pairings, were required to see the effect. Together,
the results suggest, as is often found with more traditional learning paradigms, that non-reinforcement of a flavor cue has
deleterious effects on preference learning and/or performance. 相似文献
7.
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
8.
Elizabeth D. Capaldi David E. Myers David H. Campbell Joan Denise Sheffer 《Learning & behavior》1983,11(1):107-115
In five experiments, rats’ preference for a flavor was greater if the flavor had previously been consumed under low rather than high deprivation. This preference was conditioned in as few as three flavor-deprivation pairings (Experiment 1), and persisted through 28 test days, half under each deprivation level (Experiment 2). Rats never preferred the flavor associated with high deprivation even when calories were increased by giving 40 ml of 8% sucrose or when caloric density was increased to the equivalent of 20% sucrose. The preference for the low-deprivation flavor was greater when saccharin solutions were used rather than sucrose solutions, but the preference did emerge when sucrose solutions were used as testing proceeded and when a lower concentration of sucrose was used. We suggest that these preferences may be a result of flavor-taste associations rather than associations between flavors and postingestive consequences, and that the taste of the solutions under low deprivation is preferred to the taste under high deprivation. 相似文献
9.
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
10.
Hooded Lister rats exhibited less neophobia towards (i.e., drank more of) a novel fluid (3% lemon or 5% sucrose) on a 10-min test if given a 6-min exposure to that fluid 6 h earlier. Presentation of a distractor (1.26% coffee) immediately after preexposure to the test solution enhanced neophobia habituation to lemon (Experiment 1), but disrupted habituation to sucrose (Experiment 3). This bidirectional distractor effect was not due to distractor-induced change in the hedonic value of the preexposed test flavor (Experiment 4). Evidence was obtained (Experiment 5) indicating that the rat perceives lemon to be more similar to coffee than is sucrose. It is suggested that when test flavor and distractor are dissimilar, processing of the distractor denies the preexposed test flavor sufficient processing in STM to allow encoding of information about that flavor in LTM. Consequently, the rat responds to a subsequent presentation of the test flavor as it would to a novel stimulus. When test flavor and distractor are similar, however, the distractor elicits less processing in STM (cf. Wagner, 1976) and is therefore less able to disrupt STM processing of the preexposed test flavor. The resultant loss of neophobia to the test flavor resulting from encoding of information about that flavor in LTM may then be augmented by generalization of attenuated neophobia to the distractor. Consistent with this analysis, coffee was shown to suffer more proactive interference when preceded by lemon than when preceded by sucrose (Experiment 6). 相似文献
11.
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
12.
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
13.
Rats shifted from 32% sucrose to 4% sucrose lick less than rats that experience oniy the 4% solution. Previous experiments have found this negative contrast effect to be reduced (“disinhibited”) by the addition of a novel tone in the postshift period. In Experiment 1 of this paper, the negative contrast effect was enhanced when a novel flavor was added to the sucrose solution in the postshift period. In Experiments 2–4, changes in the ambient context, even changes sufficient to produce disruptions in licking, did not alter the degree of negative contrast. Tiese results suggest that (1) rats compare rewards across substantially different contexts, (2) contrast may serve to enhance taste neophobia, and (3) a disinhibitory effect may be confined to the presentation of punctate, nontaste, novel stimuli within a familiar context. 相似文献
14.
In a series of three experiments, rats shifted from a 32% to a 4% sucrose solution, after 10 days’ exposure to the 32% solution, exhibited a negative contrast effect in lick rate. In each experiment, shifted rats that received a novel stimulus (tone) during the postshift period exhibited a higher lick rate (smaller contrast effect) than shifted subjects not receiving the tone. This increase in lick rate resembles Pavlovian disinhibition and is interpreted as supporting an inhibitory view of successive negative contrast effects. Control conditions included in Experiments 2 and 3 favored the disinhibition interpretation of the effect of the tone, as opposed to a rate-dependency hypothesis or to the nonspecific energization of behavior. In Experiments 4–6, the tone was introduced coincident with the occurrence of a simultaneous negative contrast effect. Rather than disinhibition, a decrease in licking occurred. These results were discussed in terms of differences between successive and simultaneous contrast. 相似文献
15.
Joseph W. Ternes 《Learning & behavior》1976,4(3):317-321
Sixteen rats were maintained out of doors in cages with natural light, temperature, and social stimulation for 3 months. Subsequently, by pairing the taste of sucrose with IP injections of LiCl, the rats were conditioned to avoid sucrose. Each of four groups of rats received the CS-US pairing at a different time of day. Times of conditioning were 6 a.m., 12 a.m., 6 p.m. and 12 p.m. EST. A two-bottle preference test between 4% sucrose solution and tap water was initiated 24-h after conditioning. Daily measurements of preference were continued for 16 consecutive days. Results indicated that, although all groups initially exhibited equivalent sucrose aversions, the groups conditioned at 12 a.m. and 6 p.m. extinguished within 12 days while the 6 a.m. and 12 p.m. groups continued to manifest profound aversions for sucrose throughout the 16 test days. 相似文献
16.
It has been reported previously that rats prefer a flavor they consumed under high deprivation to a flavor they consumed under low deprivation (Revusky, 1967). Here it was found that this preference occurs only if nutritive solutions are used and the flavors are given preceding and following eating. If flavors are given separately from the daily feeding, rats prefer the flavor given under low deprivation, whether or not a nutritive solution is used (Experiment 3). If flavors are given before and after the daily feeding, rats prefer the flavor they had under high deprivation (before feeding) more if sucrose solutions are used than if saccharin solutions are used and more on a high-deprivation test than on a low-deprivation test (Experiments 1 and 2). It was concluded that the “incentive value” of consumption is not necessarily higher under high deprivation than under low deprivation. The preference for the low-deprivation flavor obtained here may reflect a greater proportional rewarding effect of consumption under low deprivation or may reflect an aversion to the flavor consumed under high deprivation. Perhaps a small taste of flavor under high deprivation initiates responses of digestion that are unsatisfied and thus aversive, and the more so the higher the deprivation level. 相似文献
17.
R. A. Burns 《Learning & behavior》1976,4(4):473-479
Two experiments assessed the role of aftereffect learning in rats rewarded with sucrose solutions. In Experiment 1, rats were trained in a single straight runway for two trials on each of 18 days, each trial terminating with either large (20% scurose) or small (3% sucrose) reward. The ITI was 3–5 min. The sequence of daily rewards for each of four groups was small-small (SS), small-large, (SL), large-small (LS), or large-large (LL). Response patterning and a simultaneous negative contrast effect were observed in LS and SL relative to the consistently rewarded controls. During 10 massed extinction trials, resistance to extinction was greatest for Group SL, followed in order by Groups SS, LL, and LS. Experiment 2 examined single alternation of large and small rewards administered for 10 trials on each of 31 days with an ITI of 60 sec. Reward for one group was 20% or 3% sucrose while another received 1 or 10 45-mg Noyes pellets. Appropriate patterning developed only in the food-pellet rewarded animals. The overall results suggest that sucrose rewards may produce high-amplitude and long-duration aftereffects which interfere with learning in designs employing several massed daily trials, but which may facilitate learning—relative to food-pellet rewards—with longer intertrial intervals and fewer daily trials. 相似文献
18.
William Timberlake 《Learning & behavior》1979,7(3):277-288
Separation of the contingent and noncontingent effects of a schedule on amount of instrumental responding is desirable but difficult in schedules that involve instrumental and contingent responses that are either highly probable or very similar. Three studies in which rats were required to lick a solution of .1% saccharin for access to a preferred solution of .4% saccharin showed that neither single nor paired operant baselines of the instrumental response allowed accurate separation of the contingent and noncontingent effects of a fixed-ratio schedule. Two within-subject yoking procedures provided the best baselines of noncontingent effects: the massed baseline measured amount of .1% licking when each subject received free access to the total amount of .4% licking it obtained at asymptote under the schedule; the matched baseline measured .1% licking when each subject received the same access to the .4% solution, but presented in the intermittent pattern obtained during the schedule. Of the three algebraic models used to predict noncontingent effects, the substitution model was most promising, but still not adequate. The procedure of a between-subjects yoked control was also not effective. 相似文献
19.
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
20.
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