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1.
Eighteen Long-Evans rats were exposed to a MULT VT 30-sec EXT schedule of water presentations. The EXT schedule was signaled by a 2500-Hz, 70-dB tone. Mean number of bites of a plastic target during atone (S?) increased across sessions, whereas the mean number of target bites during the VT component signaled byno tone (S+) decreased across sessions. Changing the multiple schedule to MULT EXT EXT produced a decrease in target bites during the tone. Reinstating the original MULT VT 30-sec EXT schedule produced an increase in number of target bites during the tone (S?). Changing the multiple schedule to VT 30-sec VT 30-sec produced a decrease in target bites during the tone. The results indicate that target biting in rats increases in the presence of the exteroceptive tone (S?) of the MULT VT 30-sec EXT schedule, and that target biting during the tone varies directly with the negative correlation between tone and water presentations. 相似文献
2.
The present studies examined the effects of intermeal interval and pellet magnitude on the development and maintenance of schedule-induced polydipsia using a between-subjects design as contrasted with earlier investigations, which have exclusively employed within-subject procedures. In Experiment 1, pellets were delivered on one of six fixed-time schedules (20, 40, 60, 120,180, and 240 sec) to different groups of rats. Although the typical bitonic function relating water intake to intermeal interval was obtained, the function showed a wide plateau ranging from 60 to 180 sec. Experiment 2 demonstrated that both intermeal interval and pellet magnitude regulate schedule-induced polydipsia. While small-magnitude pellets could support drinking only at relatively short intermeal intervals, increasing pellet magnitude to medium or large resulted in drinking at progressively longer intermeal intervals. Indeed, we observed drinking on a fixed-time 720-sec schedule with large-magnitude pellets. These findings are derivable from the opponent-process theory of acquired motivation. 相似文献
3.
Two experiments tested the hypothesis that habituation contributes to within-session decreases in responding. In Experiment 1, rats’ leverpressing was reinforced under a fixed ratio (FR) 4 schedule throughout the baseline sessions. During the dishabituation sessions, the first 21 min and the last 21 min were FR 4; dishabituating events occurred during the middle 3 min. The dishabituating events altered the manner of reinforcer delivery in four different ways. Response rates increased after all dishabituating events. In Experiment 2, rats responded on several FR and variable ratio (VR) schedules. The ratio requirement varied from 3 to 15. Within-session decreases in responding were steeper during FR schedules than during VR schedules. In addition, response rates were well described as linear functions of cumulative number of food pellets eaten within sessions. These results support the habituation hypothesis but do not rule out the possibility that other satiety variables might contribute simultaneously. 相似文献
4.
Food-deprived rats that receive intermittent delivery of small amounts of food develop excessive drinking--specifically, schedule-induced polydipsia (SIP). A main characteristic of SIP is its occurrence at the beginning of interfood intervals. The purpose of this study was to demonstrate that SIP can be developed toward the end of interfood intervals, in closer proximity to upcoming than to preceding food delivery. In Experiment 1, two groups were exposed to a fixed-time (FT) 30-sec food schedule with water available during the first or the last 15 sec of each interfood interval. Two additional groups, which had access to water throughout, were exposed to FT 30-sec or FT 15-sec schedules of food presentation. The FT 30-sec group with free access to water developed the highest level of intake; similar and intermediate levels were induced in all the remaining groups. In Experiment 2, three groups of rats were exposed to an FT 90-sec food schedule with water available during the first, the second, or the last 30 sec of each interfood interval. One additional group with access to water throughout was exposed to the FT 90-sec schedule of food presentation. The group with free access to water developed a higher level of consumption than did the other groups, but by the end of training none of the four groups showed statistical differences in polydipsic drinking. Results show that adjunctive drinking can be developed in proximity to upcoming food delivery even with long interfood intervals. 相似文献
5.
In three experiments, we examined the effects of signaling reinforcement during operant responding in order to illuminate the factors underlying instrumental overshadowing and potentiation effects. Specifically, we examined whether signaling reinforcement produces an enhancement and attentuation of responding when the response-reinforcer correlation is weak and strong, respectively. In Experiment 1, rats responded on variable-ratio (VR) or variable-interval (VI) schedules that were equated for the number of responses emitted per reinforcer. A signal correlated with reinforcement enhanced response rates on the VR schedule, but attenuated response rates were produced by the signal on the VI schedule. In Experiment 2, two groups of rats responded on a VI schedule while the two other groups received a conjoint VI, negative fixed-ratio schedule in which the subjects lost the availability of reinforcements if they emitted high response rates. A reinforcement signal attenuated responding for the simple VI groups but not for the animals given the negative fixed-ratio component, although the signal improved response efficiency in both groups. In Experiment 3, a poor correlation between responding and reinforcement was produced by a VI schedule onto which the delivery of response-independent food was superimposed. A signal for reinforcement initially elevated responding on this schedule, relative to an unsignaled condition; however, this pattern was reversed with further training. In sum, the present experiments provide little support for the view that signaling reinforcement enhances responding when the response-reinforcer correlation is weak and attenuates responding when this correlation is strong. 相似文献
6.
In the first condition in Experiment 1, 6 rats were exposed to concurrent variable ratio (VR) 30, variable interval (VI) 30-sec
schedules. In the next two conditions, the subjects were exposed to concurrent VI VI schedules and concurrent tandem VI-differential-reinforcement-of-high-rate
VI schedules. For the latter conditions, the overall and relative reinforcer rates equaled those in the first condition. Only
minor differences appeared in time allocation (a molar measure) across conditions. However, local response rate differences
(a molecular measure) appeared between schedule types consistently with the interresponse times these schedules reinforced.
In Experiment 2, these findings reappeared when the prior experiment was replicated with 5 subjects, except that the VR schedule
was replaced by a VI plus linear feedback schedule. These results suggest that within the context tested, the molar factor
of relative reinforcement rate controls preference, whereas the molecular factor of the relation between interresponse times
and reinforcer probability controls the local response rate. 相似文献
7.
James V. Couch 《Learning & behavior》1975,3(4):347-358
Two experiments examined the presumed relationship between behavioral contrast and inhibitory stimulus control. In Experiment I, pigeons were exposed to mult VI 1-min VI 1-min or mult VI 5-min VI 5-min during baseline training prior to mult VI 1-min VI 5-min discrimination training. Half of the subjects received a timeout (TO) component during baseline in order to reduce the degree of contrast during discrimination training. Only 3 of 8 subjects receiving the TO showed contrast while all other subjects showed various degrees of contrast. Postdiscrimination generalization gradients indicated excitatory rather than inhibitory control by the stimulus associated with the VI 5-min schedule. During baseline training in Experiment II, responding to all the generalization stimuli was reinforced. In addition, some subjects received the TO stimulus. The subjects were next exposed to mult VI 1-min EXT, mult VI 1-min VI 5-min, or just the VI 5-min component. Generalization gradients indicated inhibitory control by the stimulus associated with EXT or VI 5-min for 19 of 20 subjects even though some subjects did not show contrast. These results question the presumed relationship between behavioral contrast and inhibitory stimulus control. 相似文献
8.
William S. Maki 《Learning & behavior》1975,3(4):312-316
In a study of sustained attention (“vigilance”), pigeons performed a conditional discrimination in a 3-key operant chamber. Pecking a white center key initiated a 0.2- or 2.0-sec cue (a red or green disk). The side keys then displayed white disks, and a peck on the right or left key was reinforced depending on whether the preceding cue was red or green. Pecks on the white center key initiated the cue according to one of two schedules of cue production (FR 1 or VI 7.5 sec). Control of side key choices by 0.2-sec cues was disturbed by transition from FR 1 to VI 7.5, and recovered after the schedule of cue production changed from VI 7.5 back to FR 1. Control of choices by 2.0-sec cues was not affected by changing schedules of cue production. Rates of pecking the cue were higher than rates of cue-producing responses. 相似文献
9.
Three experiments explored responses to molar and local schedule constraints. Thirsty rats pressed a lever for access to a water spout. In Experiment 1, response totals were unaffected by two local schedule characteristics—the variability of the instrumental requirement and the variability of the magnitude of contingent reward. Experiment 2 manipulated the correlation between the instrumental requirement and the magnitude of reward. This correlation did not affect the behavioral price ratio (presses per lick) at a molar level. At a local level, the positive correlation created a lower mean lick price than did the negative correlation. The rats licked more, and licked less efficiently, under the positive correlation than under the negative correlation. Experiment 3 compared two ways of manipulating the molar presses/lick ratio: The instrumental (contingent) series varied the instrumental (contingent) requirement, but held the other requirement constant. As the ratio increased, total leverpresses increased, and total licks decreased linearly; the two series did not differ significantly. At higher lick prices, the rats licked more efficiently and made more extra licks at the spout as it closed. The results help delimit the applicability of molar models of the organism’s response to schedule constraints. 相似文献
10.
In two experiments, the hypothesis that frustration mediates the production of schedule-induced polydipsia was tested. In Experiment I, a group in which reward was reduced from 6 to 2 pellets of food in an operant chamber was found to increase water intake compared to a group maintained at 2 pellets reward. In Experiment II, rats trained to approach food on a partial reinforcement schedule in a runway subsequently showed lower levels of water intake in the operant test for polydipsia than rats given continuous reinforcement during runway training. The results are interpreted as supporting a frustration hypothesis of schedule-induced polydipsia and are discussed within the context of persistence theory. 相似文献
11.
The aim of the four present experiments was to explore how different schedules of reinforcement influence schedule-induced
behavior, their impact on evaluative ratings given to conditioned stimuli associated with each schedule through evaluative
conditioning, and the transfer of these evaluations through derived stimulus networks. Experiment 1 compared two contrasting
response reinforcement rules (variable ratio [VR], variable interval [VI]). Experiment 2 varied the response to reinforcement
rule between two schedules but equated the outcome to response rate (differential reinforcement of high rate [DRH] vs. VR).
Experiment 3 compared molar and molecular aspects of contingencies of reinforcement (tandem VIVR vs. tandem VRVI). Finally,
Experiment 4 employed schedules that induced low rates of responding to determine whether, under these circumstances, responses
were more sensitive to the molecular aspects of a schedule (differential reinforcement of low rate [DRL] vs. VI). The findings
suggest that the transfer of evaluative functions is determined mainly by differences in response rate between the schedules
and the molar aspects of the schedules. However, when neither schedule was based on a strong response reinforcement rule,
the transfer of evaluative judgments came under the control of the molecular aspects of the schedule. 相似文献
12.
Charles H. M. Beck Thomas J. S. Huh Dave G. Mumby Marian E. Fundytus 《Learning & behavior》1989,17(1):49-62
Food-deprived rats develop polydipsia on an intermittent schedule (fixed time 60 sec) of food pellet delivery, but not on an identical schedule of food powder delivery. This result was demonstrated with separate groups receiving each type of food and was replicated using rats as their own controls. Powdered food not only prevented the development of polydipsia, but it abruptly terminated ongoing polydipsia in rats that were switched from the scheduled delivery of pellets to powder. Ethological analysis of the behavior showed that the rats receiving powder were not engaging excessively in some behavior other than drinking. After discounting several factors, we concluded that the amount of oral activity associated with feeding, which occurred immediately after food delivery, was reciprocally related to the level of drinking. 相似文献
13.
Three experiments delivered food at fixed or random intervals independently of the rat’s behavior, always less than the amount eaten with food freely available. The results revealed a Polydipsie response to this experimental suppression of eating, and total drinking decreased as total eating increased. When we added a lever that signaled each food delivery, leverpressing and drinking rose far above their baseline levels; both responses decreased as total eating increased. When a similar schedule presented lever and food independently, rats still became Polydipsie, but showed no sign of autoshaped leverpressing. A fourth experiment revealed a hypophagic response to schedules that suppressed drinking; total eating increased with total drinking. As mutual substitutes in the economic sense, one behavior falls as the other rises; as mutual complements in the economic sense, the two behaviors rise or fall together. We discuss polydipsia and autoshaping in terms of drinking as an intrinsic substitute for eating, and leverpressing as a learned substitute for eating. The results suggest a revision of conservation theory, which views drinking and eating as substitutes when the schedule suppresses eating but as complements when the schedule suppresses drinking. 相似文献
14.
Response rate (responses per minute) and response duration (time in seconds per press) were recorded in rats shifted from multiple variable-interval variable-interval (mult VI VI) to multiple extinction variable-interval (mult EXT VI). This procedure produced positive contrast (i.e., a decrease in response rate in EXT and an increase in VI) in 11 of 12 rats and, in addition, produced an increase in response duration (i.e., bar holding), which, for the most part, was confined to the EXT component of the mult EXT VI condition. One of the 12 rats showed negative induction (i.e., a decrease in response rate in both the EXT and VI components), and also an increase in response duration in both the EXT and VI components of the mult EXT VI condition. The results indicate that generalization of behavior from the EXT to the VI component can produce negative induction, and that such generalization must be prevented if positive contrast is to occur in the rat. 相似文献
15.
In three experiments, we examined the effect on the patterns of responding noted on fixed interval (FI) schedules of prior
exposure to a range of interval and ratio schedules. Rats leverpressed for food reinforcement on random ratio (RR), random
interval (RI), or variable interval (VI) schedules prior to transfer to FI schedules. In Experiment 1, prior exposure to an
RR schedule retarded the development of typical FI patterns of responding. Exposure to a yoked RI schedule produced even greater
retardation of typical FI performance. This effect was replicated in Experiment 2, using a within-subjects design. Rats responded
on a multiple RR-RI schedule prior to a multiple FI-FI schedule. Typical FI performance emerged more slowly in the component
previously associated with the RI than with that associated with the RR. In Experiment 3, exposure to an RR schedule retarded
the development of FI performance to a greater extent than did exposure to a VR schedule. The latter schedule was programmed
to allow the possibility that inhibitory control would develop after reinforcement. These results confirm that ratio schedules
independently result in the disruption of FI responding. This effect was not long lasting and cannot be used plausibly to
explain species differences in responding to FI schedules. However, it does suggest that temporal control—as manifested by
the transfer of inhibitory control from one schedule to another—could facilitate movement between interval schedules. 相似文献
16.
Reed P 《Learning & behavior》2006,34(4):379-386
Three experiments were performed to examine the effect of response force on rats’ performance on various schedules of reinforcement.
Response force was manipulated by changing the weight of the lever in the operant chamber—a heavy lever for high response
force and a light lever for low response force. Using a within-subjects design, Experiment 1 replicated previous findings
that rats respond more quickly on variable ratio (VR) than on equivalent variable-interval-plus-linear-feedback (VI+) schedules.
Experiment 2 replicated this finding but also showed that the use of a smaller response force abolished the response rate
difference between the VR and VI+ schedules. Experiment 3 used a between-subjects design and showed a response rate difference
between the VR and VI+ schedules with a high response force but no response rate difference with a low response force. This
suggests that under conditions of low force, when the rats’ responding can continue at prolonged high rates, these subjects
show little difference in their response rates between VR and VI+ schedules. These data are similar to those found for human
subjects. 相似文献
17.
In Experiment 1, rats were allowed to acquire either schedule-induced drinking or schedule-induced wood-chewing behavior under a fixed-interval (FI) 60-sec schedule of food reinforcement, following which food was omitted from 20% and then 50% of interreinforcement intervals. Omission of food severely disrupted induced drinking but had relatively little effect on induced wood-chewing. Experiment 2 investigated wood-chewing as a function of reinforcement rate, using a range of FI schedules from 5 to 180 sec in duration. Both the amount of chewing per session and the relative time spent chewing were bitonically related to reinforcement rate. In Experiment 3, schedule-induced chewing that had been acquired under a response-dependent schedule was found to persist under a response-independent schedule. Induced wood-chewing resembles other induced behaviors in important respects, but quantitative differences are also apparent. 相似文献
18.
In three experiments, we examined the effect of response-outcome relations on human ratings of causal efficacy and demonstrated
that such efficacy ratings transfer to novel situations through derived stimulus relations. Causal efficacy ratings were higher,
and probability of an outcome given a response was lower, for a differential reinforcement of high rate schedule than for
either a differential reinforcement of low rate schedule (Experiment 1) or a variable interval schedule (Experiment 2). In
Experiment 3, we employed schedules that were equated for outcome probability and noted that ratings of causal efficacy and
the rate of response were higher on a variable ratio than on a variable interval schedule. For participants in all three experiments,
causal efficacy ratings transferred to the stimulus present during each schedule and generalized to novel stimuli through
derived relations. The results corroborate the view that schedules are a determinant of both response rates and causal efficacy
ratings. In addition, the novel demonstration of a mechanism of generalization of these ratings via derived relations has
clinical implications. 相似文献
19.
Anthony L. Riley Richard L. Hyson Cory S. Baker Paul J. Kulkosky 《Learning & behavior》1980,8(2):211-217
In Experiment 1, rats poisoned following schedule-induced saccharin consumption showed a moderate reduction in the schedule-induced consumption of saccharin. With repeated poisoning, schedule-induced saccharin polydipsia was markedly reduced. Acquisition of conditioned aversion under the schedule-induced procedure was significantly slower than acquisition under water deprivation. In addition, recovery of consumption of the previously poisoned solution during extinction was more rapid under schedule-induced polydipsia. Experiment 2 revealed that schedule-induced polydipsia was less sensitive to suppression by conditioned aversions than a prandial drinking condition in which subjects were equally food deprived but were given a mass feeding instead of spaced pellet deliveries, suggesting that the relative insensitivity of schedule-induced polydipsia to conditioned taste aversions is not simply a function of different levels of food deprivation. This relative insensitivity is offered as a partial basis for the occurrence and maintenance of schedule-induced alcohol polydipsia. 相似文献
20.
Wild black-tailed prairie dogs were run on FR, FI, VR, and VI schedules for Noyes pellet reinforcement. Cumulative barpress responses, postreinforcement pause lengths, and responses per second were recorded. The highest response rates occurred in the VR schedules, with the lowest response rates coming in the FI schedules. Fixed-ratio schedules had the longest postreinforcement pauses, VI schedules had the shortest. At the upper levels of the fixed-ratio schedules (FR 90–100), the animals ceased to respond consistently. Generally, data from prairie dogs were consistent with data reported in studies from other mammalian species. 相似文献