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1.
The role of temporal uncertainty surrounding the time of US occurrence in Kamin’s two-stage blocking paradigm was studied. In Stage 1, stimulus A terminated with the onset of a .5-sec, 1-mA shock US; in Stage 2, a compound stimulus, AX, was similarly reinforced. For different groups of eight rats each, the duration of stimulus A and/or AX was either fixed or was varied from trial to trial. When the stimulus duration was fixed, it predicted the exact time of US onset; when it was varied, it did not. We suspected that uncertainty about the moment of US occurrence might enhance US “surprise.” If so, then blocking might be attenuated in the varied CS-duration conditions relative to the standard condition in which both A and AX were fixed. Within the range of temporal uncertainty studied here, however, no significant attenuation of blocking was observed. 相似文献
2.
Pigeons were trained to depress a treadle in the presence of a discriminative stimulus, either a tone or illumination of red houselights, in order to obtain access to grain or avoid electric shock. In avoidance training, the auditory discriminative stimulus yielded faster acquisition than did the visual one. In appetitive training, the visual discriminative stimulus yielded faster acquisition than the auditory one. Experiments 2 and 3 used these stimuli in Kamin’s (1969) blocking design. In Experiment 2, when the pigeons were trained to depress a treadle in the presence of tone to obtain grain and then red light was added as the redundant stimulus, the light acquired stimulus control over treadlepressing; blocking was not observed. In Experiment 3, when the pigeons were trained to depress a treadle in the presence of red light to avoid electric shock and then tone was added as the redundant stimulus, the tone acquired stimulus control over treadle-pressing. Again, blocking was not observed. The implications of these results for several models of stimulus control are discussed. 相似文献
3.
It is generally agreed that the Kamin blocking effect provides a differential test of the model of classical conditioning proposed by Rescorla and Wagner (1972), on the one hand, and the models proposed by Mackintosh (1975) and Pearce and Hall (1980), on the other. Specifically, if the blocking effect occurs with 1 compound trial, Rescorla and Wagner are supported. Experiment 1 showed that prior training with one element of a simultaneous compound stimulus prevented the added element from becoming conditioned with 10 compound trials when compared with a nonpretrained (Kamin) control. A pseudoconditioning control, which received no compound training, showed substantial suppression only on the first trial. A contextual conditioning control, which received unsignaled shock prior to compound training, was suppressed, suggesting a failure of conditioning to contextual cues. Experiment 2 demonstrated 1-compound-trial blocking using a simultaneous presentation of the compound elements. The importance of this support for the Rescorla-Wagner model is discussed in the light of other supportive studies and those which support alternative models of classical conditioning. 相似文献
4.
In three between-groups blocking experiments with rats, two concurrent and one forward, several common control procedures
were employed: Reinforced trials with the putative blocking stimulus were either omitted entirely (Kamin control), replaced
by unsignaled reinforcements (Wagner control), or replaced by reinforced trials with a different stimulus (C1 control). In
each experiment, parallel treatments with the target stimulus absent during training served to examine the possibility that
differential responding in tests with the target stimulus might be traced solely to differential exposure to the nontarget
stimuli. In Experiment 1, responding by a concurrent blocking group during the test was no different than responding by a
Kamin control group, and responding by a Wagner control group was greater than that of either of the other groups—a pattern
of results, mirrored in the performance of the target-absent groups, that could be attributed to the elevation of contextual
excitation by unsignaled reinforcement. In Experiment 2, responding in the test by a concurrent blocking group was no different
than that by a C1 control group. In Experiment 3, a finding of less responding by a forward blocking group than by a C1 control
group when the target stimulus was present during training, but not when it was absent, provided plausible evidence of blocking. 相似文献
5.
The present experiment used a transfer-of-training procedure in rabbit nictitating membrane response (NMR) conditioning to determine whether a retention interval and/or extinction could reduce associative strength. The experimental design required that groups receive 0, 3, 15, 45, 150, or 240 CS-US pairings in Stage 1. Next, the groups were given, in succession, a 10-day retention interval and 480 CS-alone trials. In Stage 2, all groups obtained 240 CS-US pairings for NMR conditioning. Another group was also employed and received only the 240 CS-US pairings in Stage 2. The results indicated that 15 to 240 CS-US pairings in Stage 1 substantially enhanced NM CR performance in Stage 2 despite the interpolation of the retention interval and CS-alone trials. When 3 CS-US pairings had been given in Stage 1, no augmentation in the NM CR performance rate occurred in Stage 2. However, the 3 CS-US pairings were effective in prohibiting the 480 CS-alone trials from retarding subsequent NM CR performance. Without any pairings in Stage 1, the 480 CS-alone trials produced strong latent inhibition of NMR conditioning in Stage 2. The data were used to support the theoretical view that associative strength resulting from CS-US pairings is relatively permanent. Moreover, the findings were relevant for an evaluation of Pearce and Hall’s (1980) recent statements concerning CS associability and the relationship between excitatory and inhibitory processes. 相似文献
6.
Although a number of studies have demonstrated nearly complete retention of fear in a conditioned suppression task, they provide little information about the nature of the memory for the CS. The purpose of the present experiment was to investigate the retention of an attribute of a tonal CS that had been paired with shock and was thus capable of eliciting a conditioned emotional response (CER) in rats. The Kamin blocking effect was utilized to detect changes in the memory of CS attributes. Either 1 or 21 days following conditioning to a tone, separate groups of rats received compound conditioning in which either the original or a novel tone was combined with a light. Subsequent measurement of suppression to the added element (light) indicated that only the original CS produced blocking at the short delay, but that both original and novel tones resulted in blocking at the 21-day interval. This increase in the extent of blocking suggests that memory for specific attributes of the CS does diminish as a function of time. 相似文献
7.
Rats were subjected to the Kamin two-stage blocking procedure. First, a stimulus, A, was conditioned and then reinforced in compound with a target stimulus, B. During compound training, an attempt was made to alleviate blocking of conditioning to B by presenting a “surprise” stimulus for 5 sec following the reinforced AB compound. The surprise stimulus consisted of the continued presentation of the previously reinforced element, A. During A training, A had never extended beyond the moment of reinforcement; thus, its extension beyond reinforcement during AB training was hypothesized to be “surprising” and, therefore, expected to alleviate blocking. Blocking in this condition was, however, just as strong as in a standard blocking condition. The results do not favor a surprise interpretation of unblocking but do seem to be consistent with other theoretical views (e.g., Rescorla & Wagner, 1972). 相似文献
8.
Barpress suppression in a 1-min interval following CS trials was investigated using 16 rats in a conditioned suppression procedure with a two-stage design. For one group, each CS co-terminated with a brief shock US in Stage 1; then, in Stage 2, only half the CSs ended with a shock, which in turn was followed 1 min later by a second shock. For a second group, the two stages were reversed. When CSs were followed by single shocks in Stage 1, posttrial suppression weakened across trials; but when, in Stage 2, double shocks followed half the CSs, posttrial suppression grew stronger. When half the trials were followed by double shocks in Stage 1, posttrial suppression was maintained at initial levels but weakened in Stage 2 when single shocks followed each trial. In both stages, posttrial suppression was stronger on nonreinforced than on reinforced trials. Two factors were hypothesized to control posttrial suppression. First, posttrial suppression weakens with training under the single-shock procedure because post-shock temporal stimuli come to inhibit fear unless themselves paired with shock. Second, posttrial suppression is stronger on nonreinforced trials than on reinforced trials because freezing behaviors initiated during the CS are not disrupted by a US and so persist into the posttrial interval. 相似文献
9.
Retention of a brightness discrimination avoidance task by rats is impaired (Kamin effect) following a 1-h training-to-test interval (TTI), is enhanced after a 3-day TTI (reminiscence, or long-term spontaneous improvement), and is disrupted following a 21-day TTI (long-term forgetting). An exposure to the conditioned stimulus (CS), delivered 5 mm before a 1-h delayed retention test, not only compensated for the performance deficit that corresponds to the Kamin effect, but induced a large improvement in performance similar to that normally obtained after a 3-day TTI. It can be proposed that such cuing may act either by accelerating a natural memory-trace maturation process or by improving the retrievability of the memory trace. Since these possibilities lead to opposite predictions concerning the length of the facilitation induced by cuing, the effect of a pretest exposure to the CS on performance obtained during a 1-h delayed retention test was studied after several cuing-to-test intervals (0, 5, 10, or 20 min). The results, which indicate that cuing transiently enhanced subsequent retention performance, more convincingly support the retrieval hypothesis. The effects of pretest exposure to the CS (which occurred 5 min before testing) were also examined 10 min, 1 h, or 24 h after initial training. The results indicate that the facilitative effect of cuing obtained when retention performance was disrupted shortly after training (1-h TTI) was also obtained after a 24-h retention interval, in the absence of performance disruption. An interpretation of the facilitative effect of a pretest exposure to the CS is proposed, and implications concerning the memory trace are further discussed in relation to the multidimensional hypothesis. 相似文献
10.
A classical conditioning procedure was instituted in which the locus of the US was changed coincidentally with the onset of the compound conditioning phase of the Kamin blocking design. The nictitating membrane of the rabbit served as the conditioning preparation. Three groups of nine rabbits each were employed: a conventional blocking group in which the US was unchanged during the simple and compound conditioning phases, a control group that received only the compound conditioning phase, and an experimental group given both simple and compound conditioning but in which the US was administered to the contralateral paraorbital region during the compound conditioning phase. Postconditioning presentations of the elements of the compound CS indicated that, relative to the control group, responding during the new element was markedly reduced in the conventional blocking group but was strongly conditioned in the group in which the US locus was changed. Implications of these findings for theoretical analyses of conditioning are discussed. 相似文献
11.
In four trace-conditioning experiments with rats, the influence on the blocking of differences between the blocking cue-unconditioned
stimulus (US) and the blocked cue-US trace intervals was explored. Experiment 1 demonstrated blocking despite the blocked
cue’s having a shorter trace interval than the blocking cue in both elemental (Phase 1) and compound (Phase 2) training. In
Experiment 2, blocking was attenuated when the blocked cue had a longer trace interval than did the blocking cue in both elemental
and compound training. In Experiments 3 and 4, the trace intervals of the two cues during compound training were matched (i.e.,
unlike in Experiments 1 and 2, neither had temporal priority). Blocking was attenuated when the blocking cue trace interval
in the elemental phase was shorter (Experiment 3) or longer (Experiment 4) than the compound cue trace during compound training.
The findings indicate that subjects encode interstimulus intervals, and they further suggest that cue competition is greatest
when the competing cues have the same temporal information as the US. 相似文献
12.
Two experiments demonstrated that transfer of training between CSs from different sensory modalities survived substantial reductions in responding to the first CS. In both experiments, animals received three stages of training. Stage 1 entailed CS-US training with a CS from one modality (e.g., light), and Stage 3 entailed CS-US training with a CS from another modality (e.g., tone). The experiments differed in treatment during Stage 2. In Experiment 1, animals either remained in their home cages or received unreinforced exposures to the first CS, which extinguished the original CR. In Experiment 2, the animals received either continued CS-US training or exposure to the CS and US but at a long interval (2,800 msec), which eliminated the original CR. As the baseline for detection of transfer effects, each experimental group had a control group that received Stage 1 training with a 2,800-msec CS-US interval, which produced minimal CR acquisition. The results of both experiments revealed substantial positive transfer across CS modalities regardless of the treatment during Stage 2. The transfer did not appear immediately on test presentations of the second CS in Stage 3. Rather, the transfer appeared as an enhancement in the rate of CR acquisition after reinforced training with the second CS had commenced. The results are discussed with respect to stimulus generalization, neutralization of background stimuli, and learning processes superordinate to specific associations. 相似文献
13.
In Experiment 1, rats experienced presentations of a discrete visual stimulus (Stage 1) until habituation of the orienting response (OR) occurred. On a test session given after an interval of 16 days (Stage 2) the OR reappeared. For control subjects that received no Stage 1 training but presentations of the light in Stage 2, habituation persisted during the test. All subjects then received conditioning trials on which the light preceded the delivery of food. They showed latent inhibition, acquiring the conditioned response less readily than control subjects that had not previously experienced the light. Experiment 2 confirmed that the latent inhibition effect survived the retention interval for subjects that received no habituation test session. This pattern of results implies that habituation of the OR and latent inhibition are determined by different mechanisms. 相似文献
14.
The growing emphasis on teachers as ‘reflective’ and ‘expert practitioners’ has led to a noticeable increase in action research involving a wide range of educational practitioners as well as professionals from the academic community. In the light of the complex demands frequently faced by action researchers, this article examines the ethical considerations involved in conducting a collaborative action research project which is concerned with children’s experiences of transition from Key Stage 2 to Key Stage 3. By exploring a range of theoretical and practical perspectives the discussion focuses on the problematic issue of ‘informed consent’. The article argues that, as a result of having to comply with the regulations imposed by institutional ethics committees, educational researchers, particularly when working with children, are often restricted in exercising the moral autonomy and professional discretion required to negotiate the complex, potentially conflicting imperatives confronting them. 相似文献
15.
Kathy Durkin 《Literacy》1997,31(2):42-48
Redrafting is clearly a crucial part of the writing process and teachers are currently required to teach children to redraft writing at Key Stage 2 in the National Curriculum. For Kathy Durkin this is much too late and she reports here on her investigations into introducing redrafting to Key Stage 1 children. From her work it seems there are many dangers in under-estimating children’s abilities in this regard. 相似文献
16.
杨莹 《宁波教育学院学报》2020,(1):76-78
马伏里奥是莎士比亚《第十二夜》中不可忽视的一个角色。从雅克·拉康的镜像阶段理论来看,马伏里奥对自我定位不够准确,将真实自我与信件描绘的理想自我统一起来,在自己和他人制造的幻象之镜里误认了自己的身份。剧中如奥丽维娅、玛利娅、信件这样的他者,误导了马伏里奥对自我的准确定位,使其自我产生"主体异化"的现象。他既对自己在奥丽维娅府中的身份定位缺乏清醒认知,又无法识破他人的诡计,稳固自己的管家职位,提升自己在府中的权威,因而导致其试图建构自我形象的失败。 相似文献
17.
In Stage 1, four groups of pigeons were given true discrimination (TD) and four groups were given pseudodiscrimination (PD) training along one of two dimensions orthogonal to wavelength. In Stage 2, all groups received single stimulus (SS) training with a wavelength cue compounded with the former S+ for four of the groups (two TD and Two PD) and with a novel stimulus for the other four (two TD and two PD). For all groups, the SS training was followed by a wavelength generalization test in order to assess the control acquired by the (incidental) wavelength cue during Stage 2. The presence of the former S+ should have blocked the acquisition of control by the wavelength cue leading to flat generalization gradients in the appropriate TD groups. To the contrary, however, these groups showed the sharpest wavelength gradients, i.e., rather than blocking, potentiation was found. One possible interpretation is that the superimposition of the previous S+ served as a reminder of previous TD training, thereby enhancing the transfer of an attentive set from Stage 1 to Stage 2. An alternative conditioning interpretation, suggested in a 1975 paper by Mackintosh, can also be extended to encompass these results. 相似文献
18.
Maria Mroz 《International Journal of Early Years Education》2006,14(1):45-61
This paper discusses the knowledge, skills and understandings of Foundation Stage teachers in relation to children’s speech and language development. Results from a questionnaire to 294 teachers reveal limited initial and post qualification training. Teachers’ knowledge of specific aspects of children’s language revealed that key areas for training were centred on the identification of children who may have speech and language difficulties and speech sound development. The discussion centres on how changes to the curriculum in initial teacher training, in the consolidation of the revised Special Educational Needs Code of Practice and in the assessment requirements within the Foundation Stage may impact on teachers’ knowledge of speech and language development and on their ability to identify children who have speech and language difficulties. 相似文献
19.
刘金锋 《西安文理学院学报》2014,(3):122-124
利用2012—2013赛季WCBA官网的技术数据统计,将WCBA常规赛的11个技术统计数据进行了逐步回归分析,得出了数学模型.研究表明2分球命中率、3分球命中率、盖帽、被侵是影响女篮得分能力的主要因素;对WCBA各队的训练提供建议,提高球队的竞技能力. 相似文献
20.
Rosemary Butt 《International Journal of Inclusive Education》2013,17(2):207-219
Research has shown that teaching assistants (TAs) working in mainstream classrooms with special needs students in Australia are being required to perform quite complex tasks such as curriculum modification and differentiation yet they are not required to have any formal qualifications nor training in these tasks. In the United Kingdom, TAs are not required to have any formal qualifications, while TAs employed in the USA are required to hold a two-year post-secondary degree or have obtained an associate’s or higher degree. Initial research was undertaken in Stage 1 to identify the roles and responsibilities, skills and training needs of TAs working with special needs students in one school in Canberra, Australia. Information was obtained through separate focus group interviews conducted with class teachers and TAs. Stage 2 involved the design and implementation of five skills-based training modules developed to respond to needs identified in Stage 1. In Stage 3, interviews were conducted with the TAs to determine the effect the training had on their skills and their ability to assist both the class teachers and the students whom they support. Results from the study indicate that there exists role confusion as well as a different emphasis and perception by class teachers and TAs of the skills required to perform in the role of a TA. Results also indicated that specifically targeted skills-based training benefited the TAs and the TAs perceived that this benefit flowed through to the class teachers and the students they support. 相似文献