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1.
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
2.
Schedule-induced polydipsia was studied using a behavioral contrast paradigm. Food pellets were delivered to food-deprived rats on a response-independent FT 1-min schedule. Licking on a tube produced water on a MULT FR 10 FR 10, MULT FR 10 EXT, or MIXED FR 10 EXT for three rats (Experiment 1) and on a MULT VI VI, MULT VI EXT, or MIXED VI EXT schedule for three other rats (Experiment 2). On the FR schedules, rats could drink more water by increasing lick rates, but on the VI schedules the amount of drinking was fixed by the schedule parameters and was relatively unaffected by lick rates. Relative to MULT FR FR, positive polydipsia contrast was clearly demonstrated on MULT and MIXED FR EXT; but relative to MULT VI VI, contrast was not demonstrated on MULT and MIXED VI EXT. These data suggest that polydipsia contrast occurs only if increased licking permits increased drinking. 相似文献
3.
Two experiments with goldfish were performed to investigate the role of stimulus-reinforcer vs. response-reinforcer relationships in omission training and the role of stimulus localizability in a positive behavioral contrast paradigm. The directed behavior of fish, like that of pigeons and rats in other studies, was greatly influenced by positive stimulus-reinforcer correlations, as evidenced by maintained contacts of a signal for food, even though such responses terminated the signal and cancelled reinforcement delivery. Goldfish exhibited positive behavioral contrast when the signals for reinforcement and nonreinforcement were displayed directly on the response key, but no contrast was observed when variations in a diffuse houselight stimulus were used as signals for reinforcement or nonreinforcement. Analysis of sequential-trial data yielded effects analogous to Pavlovian positive and negative induction. Theoretical and methodological problems were briefly considered. 相似文献
4.
Two strains of rats (albino Wistar and hooded PVG/c) were exposed to a conditioned defensive burying paradigm that consisted of placing rats in a test chamber with bedding material on the floor, shocking them with a shock prod, and recording the time each rat spent in burying responses toward the prod. Various behaviors other than burying (freezing, grooming/paw licking) were observed by a time-sampling procedure during the control, conditioning, and extinction sessions, each of which was 15 min in duration. Wistar rats generally showed behavioral inhibition, as evidenced by less burying, lower exploratory and ambulatory behavior, and higher freezing behavior. PVG/c rats spent significantly more time engaged in burying and accumulated more bedding material in the conditioning session than did the Wistar rats. No significant differences between the two strains of rats were observed during the extinction session in terms of these measurements. The results indicate that Wistar rats have a greater tendency to freeze when coping with the noxious stimulus in a conditioned defensive burying paradigm, whereas the dominant coping style for PVG/c rats is defensive burying. 相似文献
5.
The effects of age on the forgetting of stimulus attributes in a differential fear-conditioning paradigm were examined with
18- and 70-day-old rats tested in either the original conditions or shifted stimulating conditions at one of three retention
intervals (1, 48, and 120 h). Adults displayed significant shifts at each retention interval, with those tested in the original
context displaying greater fear than those tested in the shifted conditions. By contrast, by 48 h the 18-day-olds had forgotten
the specific attributes of the training situation and began treating the two stimulating conditions as functionally equivalent
(Experiment 1). In Experiment 2, we tracked the ontogenetic emergence of adult-like memory for stimulus attributes and found
a dramatic increase in memory capability by 25 days of age. Experiment 3 illustrated that the forgotten memory attributes
of infants may be retrieved by administering a 90-sec cuing treatment 10 min prior to the 48-h test. Implications for the
phenomenon of infantile amnesia are discussed. 相似文献
6.
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
7.
Whereas rats exposed to a series of progressively decreasing shock durations show deficits in shuttle-escape performance 24 h later, the same number and intensity of shocks in the reverse (increasing) order of durations does not produce the “learned helplessness” effect (Balleine & Job, 1991). We conducted two experiments to establish the generality of this shock-duration order effect on other measures of distress and helplessness in rats. In Experiment 1, rats exposed to decreasing durations of inescapable shock showed reduced consumption of quinine-adulterated water (finickiness), whereas increasing durations produced no finickiness. By contrast, increasing shock durations produced greater conditioned fear to the shock context than did decreasing shock durations in Experiment 2. The differential effects of shock-duration order on finickiness and fear are explicated in terms of the specificity of fear conditioning during exposure to increasing versus decreasing series of shock duration orders. 相似文献
8.
Mark J. Gierl 《Educational Measurement》2005,24(1):3-14
In this paper I describe and illustrate the Roussos-Stout (1996) multidimensionality-based DIF analysis paradigm, with emphasis on its implication for the selection of a matching and studied subtest for DIF analyses. Standard DIF practice encourages an exploratory search for matching subtest items based on purely statistical criteria, such as a failure to display DIF. By contrast, the multidimensional DIF paradigm emphasizes a substantively-informed selection of items for both the matching and studied subtest based on the dimensions suspected of underlying the test data. Using two examples, I demonstrate that these two approaches lead to different interpretations about the occurrence of DIF in a test. It is argued that selecting a matching and studied subtest, as identified using the DIF analysis paradigm, can lead to a more informed understanding of why DIF occurs. 相似文献
9.
Andrés Molero-Chamizo 《Learning & behavior》2017,45(2):157-163
Latent inhibition of conditioned taste aversion (CTA) is sensitive to changes in the temporal context. A change in the time of day of conditioning with respect to the time of day of the preexposure can disrupt the latent inhibition. This contextual change in the time of day may reveal a temporal specificity of latent inhibition. The optimum procedure to induce this temporal specificity is not well established. For example, it has been shown that a long period of habituation to temporal contexts is one factor that can determine the effect. However, the experimental conditions on the conditioning day that facilitate this phenomenon are unknown. The aim of this study is to elucidate whether a restriction in the intake of the conditioned taste stimulus affects the temporal specificity of latent inhibition. Two main groups of Wistar rats were tested in a latent inhibition of CTA paradigm, in which the temporal specificity of this phenomenon was analyzed by a change in the time of day of conditioning. The intake of the taste stimulus was restricted in the conditioning day in one of the groups, but this restriction was not applied in the other group. The results indicated temporal specificity of latent inhibition only in the group without restriction, but not in the group with limitation in the intake of the taste stimulus during conditioning. These findings can help to elucidate the characteristics of the procedure to induce temporal specificity of latent inhibition. 相似文献
10.
In three experiments that used appetitive preparations with rats, we examined the effects of reinforcing a compound consisting of two previously reinforced stimuli on subsequent responding to those stimuli. Experiment 1 showed that a Pavlovian conditioned stimulus given this treatment evoked fewer magazine entries when presented alone than did a reinforced stimulus that did not receive the compound treatment. Experiment 2 examined inhibition of delay and generalization decrement accounts for the results of Experiment 1. Experiment 3 extended this finding to an instrumental learning paradigm. 相似文献
11.
在传统的用户/服务器网络结构中,本地数据需要传送到目的地去进行计算和处理,而移动代理的出现则使移动计算变为了现实.移动代理的移动性使之比用户/服务器网络结构更适用于传感器网络.本文提出了一种适用于传感器网络的通用移动代理结构.这种结构称为基于移动代理的传感器网络(MAWSN).本结构中的移动代理可以从以下三个方面减少信息冗余度和通信的额外开销以延长网络的生存时间:①通过本地处理功能减少应用层的冗余度;②通过数据汇聚功能减少数据的空间冗余度;③通过多目标数据融合功能减少通信的额外开销. 相似文献
12.
Dogs are thought to evaluate humans’ emotional states, and attend more to crying people than to humming people. However, it is unclear whether dogs would go beyond focusing attention on humans in need by providing more substantive help to them. This study used a trapped-other paradigm, modified from use in research on rats, to study prosocial helping in dogs. A human trapped behind a door either cried or hummed, and the dog’s behavioral and physiological responses (i.e., door opening and heart rate variability) were recorded. Then, dogs participated in an impossible task to evaluate gaze at the owner as a measure of the strength of their relationship with their owner. Dogs in the distress condition opened at the same frequency, but significantly more quickly, than dogs in the control condition. In the distress condition, the dogs that opened showed lower levels of stress and were able to suppress their own distress response, thus enabling them to open the door more quickly. In the control condition, opening was not related to the dog’s stress level and may have instead been motivated by curiosity or a desire for social contact. Results from the impossible task suggest that openers in the distress condition may have a stronger bond with their owner than non-openers, while non-openers in the control condition showed a stronger bond than openers, which may further suggest that the trapped-other paradigm is reflective of empathy. 相似文献
13.
In contrast to the plethora of literature that suggests that the increasing gulf between teachers and young people is due to the shifting interests and expectations of young people, the focus of this paper is on the roles teachers play in this relationship. Provoking our interest is a concern that some of the assumptions that underpin ‘mainstream’ pedagogic theory and practice might actually contribute, albeit unwittingly, to hardening rather than softening the communication divide. Drawing on an incident that took place between a group of 7–8 year old males in a primary school setting, we reveal the limits of a teaching paradigm that encourages teachers to adopt authoritative positions from which to separate and individualise student behaviour. In theoretical terms, we argue that the application of this paradigm asserts an exaggerated notion of agency to individuals in the construction of identity. In practical terms it promotes processes that individualise behaviour as a way of dealing with miscreance. Together these manifest themselves as a ‘pedagogy of separation’. The process of building more productive pedagogic relationships, we conclude, needs to begin with teachers better recognising and engaging with the collective investments of young people. 相似文献
14.
Scott H. Deibel Matthew L. Ingram Andrew B. Lehr Hiliary C. Martin Darlene M. Skinner Gerard M. Martin Isaac M. W. Hughes Christina M. Thorpe 《Learning & behavior》2014,42(3):246-255
It is difficult for rats to acquire daily time–place (TP) learning tasks. One theory suggests that rats do not use time of day as a stimulus signaling a specific response. In the present study, we tested rats’ ability to use time of day as a discriminative stimulus. A fixed-interval procedure was used in which one lever provided reinforcement on a FI-5-s schedule in morning sessions, and the same lever provided reinforcement on a FI-30-s schedule in afternoon sessions. Because only one place was used in this paradigm, the rats could only use time of day to acquire the task. Mean responses during the first 5 s of the first trial in each session indicated that the rats did not discriminate between the two sessions. In Phase II, a different lever location was used for each of the two daily sessions, which meant that both spatial and temporal information could be used to acquire the task. The rats readily acquired the task in this phase, and probe trials indicated that the rats were using a combination of spatial and temporal information to discriminate between the two different trial types. When the spatial cue was removed in Phase III, rats no longer discriminated the two sessions, suggesting that time can only be used as a discriminative stimulus when each daily session is associated with a distinct spatial location. 相似文献
15.
James D. Dougan Valeri A. Farmer-Dougan Frances K. McSweeney 《Learning & behavior》1989,17(2):247-255
The effects of reinforcement rate on behavioral contrast were examined in pigeons and rats. Each species was exposed to a series of 12 multiple variable-interval schedules, divided into four 3-schedule series. Each series consisted of a standard contrast manipulation, and baseline schedules provided a different rate of reinforcement in each of the series. The functions relating reinforcement rate to the magnitude of contrast were different across species. Rats showed a U-shaped function, with reliable contrast occurring only at high reinforcement rates. Pigeons showed an inverted U-shaped function, with contrast occurring on all schedules except the schedule providing the lowest rate of reinforcement. Pigeons discriminated between schedule components better than rats did, although differences in discrimination were probably not responsible for the differences in contrast. The results suggest that behavioral contrast in rats may be a different phenomenon from behavioral contrast in pigeons. The results cannot be explained by current theories, which view contrast as the product of a single general process. 相似文献
16.
Time spent in various behaviors by the rat was recorded in a defensive burying paradigm. Experiment 1 revealed that rats spent more time burying the shock prod than a control prod and that doubling the size of the test chamber did not have a significant effect on the time spent in any behavior. In Experiment 2, the location of bedding material in a two-compartment test chamber was found to affect the occurrence of burying (both the shock and control prods) and burrowing behavior. Burying did not occur when bedding was not available in the shock compartment but was located in the escape compartment. Burrowing was more likely to occur when bedding was in both compartments than when it was in only one compartment. Immobility and escape latencies were shorter than burying latencies in all subjects. Burying was viewed as belonging to a second stage of defensive behavior. 相似文献
17.
当前进化心理学理论范式的困难是缺乏认知领域的实验证据,而归纳推理研究则面临解释匮乏的困难。文章指出,通过进化心理学理论范式来解析归纳推理的心理机制可以解决两者的困难。进化心理学的功能分析的研究方法和领域特殊性的观点为归纳推理的解释提供了新的出路,归纳推理的实证研究则可以在认知领域为进化心理学提供实验支持。通过分析,文章提出,归纳推理是进化而来的领域特殊性适应机制。 相似文献
18.
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
19.
The present study employed a Pavlovian-instrumental-transfer paradigm to investigate the role of conditioned fear in appetitive discrimination learning. Each of three Pavlovian training procedures was used to establish a conditioned fear excitor (CS+), a “neutral” CS (CSo), and a conditioned fear inhibitor (CS?). Then, the CSs were administered to rats in the three groups contingent upon the rewarded response in a difficult visual discrimination. In addition, half of each group received shock punishment for each incorrect response. Relative to CSo, CS+ facilitated performance in contrast to the usual interfering effect of conditioned suppressors; conversely, CS? retarded performance even when its reinforcing action (fear inhibition) was potentiated by punishment for the incorrect response. These results, together with other findings showing a reversed outcome when the CSs are administered for the incorrect response, indicate that Pavlovian conditioning comprises both general signaling and affective functions, the former reflecting a basic “expectancy” or nominal type of cognitive processing in the rat. 相似文献
20.
Rudi K. Bresser 《Research in higher education》1984,20(1):3-15
This study demonstrates that the concept of paradigm development can explain differences in organizational contexts of university departments. Departments from high-paradigm fields are embedded in a context with clearly identifiable and distinguishable dimensions. In contrast, departments representing lower levels of paradigm development have unclear contexts where major dimensions like size and technology cannot be distinguished from one another. The implications of these results are discussed and elaborated. 相似文献