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1.
In a series of related experiments, we studied associative phenomena in snails (Helix aspersa), using the conditioning procedure of tentacle lowering. Experiments 1A and 1B demonstrated a basic conditioning effect in which the pairing of an odor (apple) as the conditioned stimulus (CS) with the opportunity to feed on carrot as the unconditioned stimulus (US) made snails exhibit increased levels of tentacle lowering in the presence of the CS. Experiments 2 and 3 showed that the magnitude of the conditioning was reduced when snails were exposed to the CS prior to the conditioning trial (a latent inhibition effect). Experiment 4 examined the effects produced by pairing a compound CS (apple—pear) with food presentations and demonstrated the existence of an overshadowing effect between the two odors. Experiment 5 revealed that pairing one CS with another previously conditioned stimulus increased tentacle lowering to the new CS (a second-order conditioning effect). Finally, Experiment 6 showed that pairing two odors prior to conditioning of one of them promoted an increase in tentacle lowering in response to the other (a sensory preconditioning effect). The results are discussed in terms of an associative analysis of conditioning and its implications for the study of cognition in invertebrates.  相似文献   

2.
Five experiments are reported in which rats were given CS-shock pairings and then permitted, in the absence of shock, to perform a hurdle-jump response that led to CS offset. In Experiment 1–4, the animals failed to learn the required response. Although several procedural variations were employed, the experimental groups continued to perform no better than backward-conditioned controls. In Experiment 5, some animals were punished for remaining immobile during a single trial at the start of hurdle-jump training. These animals performed significantly better than nonpunished controls and better than any group in Experiments 1–4. The results support the idea that the major role of the CS in escape-from-fear situations is to activate an innate motivational system which chooses between the species-specific defense reactions of freezing and fleeing.  相似文献   

3.
Reinstatement after counterconditioning was examined in three experiments with rats. The rats received CS-shock pairings in Phase 1 and then CS-food pairings in Phase 2. When unsignaled shock was presented after appetitive conditioning, fear performance to the CS replaced food performance. This reinstatement effect depended on initial pairings of the CS and shock in Phase 1. It also depended on shock exposure occurring in the test context. The results parallel previous data obtained after extinction. Counterconditioning and extinction yield several parallel effects (spontaneous recovery, renewal, and now reinstatement) which suggest that Phase 2 does not destroy the learning acquired in Phase 1.  相似文献   

4.
In two experiments using the shuttlebox apparatus and negative (shock) reinforcement, goldfish learned to discriminate between same color signals differing only in brightness and to choose the brightness level paired with shock-omission to avoid shock. Experiment 1 compared two signal presentation procedures, one presenting only one signal at a time but allowing for successive alternation of signals within a trial (SUC) and the other presenting both signals simultaneously (SIM). SIM performance was superior to SUC in acquisition and showed more positive transfer with signal color changed (CC), more negative transfer with brightness-level—shock pairing reversed (R), and, although attenuated, more negative transfer with both signal color changed and shock pairing reversed (CC + R). Further, SIM relearning following reversal was faster than SUC. In Experiment 2, using the SIM procedure, eight transfer groups were tested for transposition with one of their original acquisition signals replaced in transfer by a signal bearing either the same or the opposite brightness relationship to the retained signal. Four transfer groups showed positive and four showed negative transfer effects, but all eight groups showed transfer performances consistent with a transpositional expectation. The present two experiments alone do not elucidate the mechanisms accounting for either the SIM superiority over SUC in Experiment 1 or the transposition effect in Experiment 2. These experiments show only that the transposition phenomenon can be supported by negative reinforcement procedures, which has not been demonstrated before. Now that techniques exist for producing negatively reinforced transposition, work investigating the underlying mechanisms and comparing them with the mechanisms of positively reinforced transposition can begin.  相似文献   

5.
The effect of tail-handling on exploratory behavior of the rat, measured as step-through latency in a well-lighted, two-box apparatus, was investigated. Male adult Wistar rats, aged 60 days, were employed in all three experiments. Experiment 1, in which the subjects were handled at different times after entering the goal chamber (0, 10, 30, 60, 300, and 600 sec), showed that immediate handling, relative to detention in the goal chamber (delay of handling) had an inhibitory effect on exploration. Experiment 2 showed that groups handled immediately after entering the goal chamber but then detained there for different durations all showed the same progressive inhibition of exploration. Experiment 3 showed that the inhibition of exploration (very long step-through latencies) due to tail-handling immediately after entering the goal chamber could be significantly decreased by further trials in which handling was delayed for a sufficient duration (30 sec or more). Handling is discussed as a stimulus that is aversive enough to elicit conditioned passive-avoidance responses (inhibition of exploratory behavior), although it is subject to rapid extinction.  相似文献   

6.
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   

7.
The co-benefit of hazardous trace elements such as mercury (Hg), arsenic (As), and selenium (Se) capture in dust removal devices of ultra-low emission coal-fired power plants was investigated. Feed fuel and ash samples collected from 15 different coal-fired power units equipped with ultra-low emission systems were characterized to determine the concentrations and distribution characteristics of trace elements. It was found that the low-low temperature electrostatic precipitator (LLT-ESP) and the electrostatic fabric filter (EFF) had greater abatement capacity for Hg than normal cold-side ESP (CS-ESP). Only 0.8%–36.1% of Hg escaped from LLT-ESP and EFF, whereas 42.1%–90.6% of Hg escaped from CS-ESP. With the employment of EFF and ESP (inlet temperature<125 °C), 72.3%–99.1% of As and 70.7%–100% of Se could be captured before the wet flue gas desulfurization (WFGD) system. The significance level of the effects on the abatement capacity for Hg, As, and Se in ESP were analyzed by the Pearson correlation analysis and grey relational analysis. The results indicated that the low inlet temperature of LLT-ESP had significant promotional effect on the simultaneous removal of Hg, As, and Se. The smaller particle size of fly ash can be conducive to the adsorption of hazardous trace elements. The inhibitory effect of sulfur content in coal was significant for the enrichment of Hg and Se in fly ash.  相似文献   

8.
In three experiments, thirsty rats were trained to make several instrumental responses whose outcomes differed in which of two relatively inconsequential flavor features they contained. In Experiment 1, one of the features was subsequently devalued by pairing it with lithium chloride; in Experiment 2, it was enhanced in value by pairing it with sucrose. In both experiments, differences in the value of the features resulted in parallel differences in the likelihood of the responses during a subsequent extinction test. In Experiment 3, the animals chose between these responses in the presence of discriminative stimuli that had signaled the occurrence of these different features following another response. The stimuli selectively augmented the likelihood of the response with which they shared training by the same-flavored consequence. These results indicate that rats can separately encode features that differ along one dimension, both in the association between an instrumental response and its outcome, and in the association between a discriminative stimulus and that outcome.  相似文献   

9.
Two experiments investigated the capacity of a nominal CS to overshadow background stimuli. Rats received CS-shock pairings in one compartment of a double-compartment apparatus. After training, the shock compartment was re-presented but in the absence of both the CS and shock, and overshadowing was assessed by measuring the rats’ latency to enter the compartment. In the first experiment, predictive values of temporal cues provided by CS onset and CS offset were manipulated. Rats readily entered the shock compartment, provided shock onset had previously been predicted by CS onset or CS offset. This indicates that background cues in the shock compartment had acquired little associative strength during training. In contrast, rats avoided the shock compartment under every condition in which shock onset had not previously been predicted by either CS onset or CS offset. In the second experiment, a precise temporal cue provided by CS onset was dissociated from other factors arising from CS-shock contiguity. It was found that rats’ reactions to the shock compartment after training was governed by both temporal and contiguity factors. The results are relevant to theories which state that conditioning is a function of a competitive relationship between stimuli present in an animal’s environment during training.  相似文献   

10.
Three experiments used a compound test procedure to evaluate whether superior conditioning results from the pairing of stimuli that are related to each other. In each case, a stimulus compound was tested after its component conditioned stimuli (CSs) had been conditioned by the same unconditioned stimuli (USs) arranged such that either related or unrelated CSs and USs were paired. Experiment 1 explored auditory and gustatory stimuli conditioned by LiCl or shock, using rats. Experiments 2 and 3 used second-order conditioning in pigeons to pair stimuli that were similar by virtue either of qualitative features or of shared physical location. In each case, the compound test provided clear evidence that pairing related stimuli produces superior associative learning.  相似文献   

11.
In Experiments 1 and 2, rats were exposed to two compound flavors, AX and BX, containing one flavor in common (X). Following this exposure phase, an aversion was conditioned to A in the experimental group by pairing its consumption with an injection of lithium, while a control group drank A without being poisoned. The effect of this treatment was to establish B as a conditioned inhibitor. In Experiment 1, experimental animals were slower than controls to condition an aversion to B when its consumption was paired with lithium (a retardation test of conditioned inhibition). In Experiment 2, B alleviated the suppression of intake of another flavor previously paired with lithium (a summation test). Experiments 3 and 4 established that these effects depended upon prolonged prior exposure to AX and BX.  相似文献   

12.
In four experiments, each using a single conditioning trial, rats avoided a light more than a saccharin solution after these stimuli had been paired with footshock, whereas saccharin was avoided more than the light after these stimuli had been paired with lithium injection. The use of a single conditioning trial precludes possible US-induced differential orientations from influencing which stimuli will be associated on the conditioning trial. This cue-consequence specificity effect was obtained even when subjects conditioned with lithium received a non-contingent footshock prior to the test session, and when subjects conditioned with footshock received a noncontingent lithium injection before testing (Experiments 2–4). Weak aversions to the light in rats given a light-lithium pairing and noncontingent footshock and to the saccharin in subjects that received a saccharin-footshock pairing and noncontingent lithium administration were obtained in Experiment 2. However, these weak aversions were not obtained when subjects were given three nonreinforced exposures to the test chamber before the test session (Experiments 3 and 4). These results indicate that US-induced differential orientations do not mediate the cue-consequence effect in aversion learning.  相似文献   

13.
Two experiments were conducted to investigate functional similarities between “hunger CRs” of Konorski’s (1967) model of appetitive classical conditioning and sign-tracking behavior in rats. Konorski’s model predicts that hunger CRs will be facilitated (1) when a nonrein-forced stimulus similar to the reinforced CS is introduced, and (2) when some CS presentations are unexpectedly nonreinforced. In Experiment 1, hungry rats acquired a leverpress response to a retractable lever that was paired with response-independent food. Following this training, a second lever was introduced whose presentation was not followed by food. The effect of the presence of this second lever was to facilitate responding to the original lever. In Experiment 2, single-lever autoshaping training was followed by a shift from 100% pairing of the lever with food to only 50% of the lever presentations being followed by food. The introduction of partial reinforcement produced an immediate and durable increase in leverpressing. The findings of both experiments are consistent with predictions from Konorski’s model of classical conditioning if sign-tracking is considered as a “hunger CR.”  相似文献   

14.
In three experiments, the nictitating membrane response of rabbits was conditioned for 10 daily sessions at interstimulus intervals (ISIs) ranging from 48 to 125 msec, followed by a shift to 250 msec for 5 days. At tested ISIs shorter than 67 msec, there was no evidence of conditioning, and postshift performance revealed neither facilitation nor interference as a result of the first 10 conditioning sessions. Postshift performance of groups conditioned at preshift ISIs of 67 msec or longer revealed a gradient of increasing savings with increasing ISI. One of the groups in Experiment 1, initially conditioned at 250 msec ISI and then shifted to 48 msec, exhibited extinction of the previously well-conditioned response. Analysis of CR-onset latencies substantiated the absence of associative effects at very short ISIs. It was concluded that there is a temporal limit below which classical conditioning of the nictitating membrane response of rabbits employing forward CS-US pairing does not occur.  相似文献   

15.
通过构建家庭环境影响小学生学习表现的基本机制并运用结构方程模型、多元线性回归分析等方法对770名参与新教育实验“家校合作共育”行动和726名未参与这一行动的小学生进行配对抽样并分析,结果发现:家庭环境通过学生学习投入、学校环境等中介变量对小学生学习表现产生显著作用,学校环境能够直接对小学生的学习投入和学习表现产生显著的正向作用,家校合作共育能够显著改善小学生学习表现。新教育实验学校学生的家庭藏书量显著高于非新教育实验学校的学生,新教育实验学校学生在阅读表现和数学表现上存在显著优势。学校参与新教育实验“家校合作共育”行动的时间越长,其学生的阅读表现和数学表现明显更好。为强化家庭环境对小学生学习表现的积极影响,在兼顾学生性别、年龄以及学校所在地区等因素的同时,可通过打造家庭书屋、创建书香校园、推进每月一事、优化家校合作等方式强化家庭环境对小学生学习表现的积极影响。  相似文献   

16.
In five experiments, a Pavlovian appetitive conditioning preparation was used with rats to explore the interaction of associations with different, but equivalently valued, outcomes. Experiment 1 demonstrated summation in magazine responding when two stimuli previously associated with different outcomes were combined. Experiments 2A and 2B found that pairing that stimulus compound with one of the outcomes led to a decrease in performance (overexpectation) for both of the stimulus elements. Experiments 3A and 3B confirmed that result but demonstrated the continued presence of the original stimulus-outcome associations. The results are consonant with a view in which replacing one outcome with another leads to an associative structure containing both stimulus-outcome associations and an outcome-independent depressive process.  相似文献   

17.
Three experiments investigated the fact that the static visual features of an imprinting object (its color, size, and shape characteristics, as represented by the object remaining stationary during its presentation) can gradually acquire control over filial behavior by virtue of their repeated spatial-temporal pairing with visual motion—an effect that has been interpreted as a process of classical conditioning. Experiment 1 found that the static features can acquire control if they are made conspicuous in some other, nonmovement way (i.e., by manipulating the relative illumination of the imprinting object). Further experiments then failed to find any qualitative difference between the behavioral control developed by conspicuous but static aspects of a duckling’s environment and the control developed by the static features of a moving object, either in terms of persistence of the acquired control (Experiment 2) or in terms of possible restrictions imposed by the sensitive period for imprinting (Experiment 3). Taken together, these results support the plausibility of a perceptual learning hypothesis, although the classical conditioning view was not itself contradicted. The present findings are also relevant to the broader issue of whether any valid distinctions exist between the behavioral control exerted by static aspects of a precocial bird’s environment and the control exerted by animate, presumably social stimuli.  相似文献   

18.
Binge eating is often associated with stress-induced disruption of typical eating patterns. Three experiments were performed with the aim of developing a potential model for this effect by investigating the effect of presenting response-independent stimuli on rats’ lever-pressing for food reinforcement during both fixed-interval (FI) and fixed-ratio (FR) schedules of reinforcement. In Experiment 1, a response-independent brief tone (500-ms, 105-dB, broadband, noisy signal, ranging up to 16 kHz, with spectral peaks at 3 and 500 Hz) disrupted the performance on an FI 60-s schedule. Responding with the response-independent tone was more vigorous than in the absence of the tone. This effect was replicated in Experiment 2 using a within-subject design, but no such effect was noted when a light was employed as a disrupter. In Experiment 3, a 500-ms tone, but not a light, had a similar effect on rats' performance on FR schedules. This tone-induced effect may represent a release from response-inhibition produced by an aversive event. The implications of these results for modeling binge eating are discussed.  相似文献   

19.
The instructional effect of worked examples has been investigated in many research studies. However, most of them evaluated the overall performance of the participants in solving post-intervention problems, rather than individual step performance in multi-step problems. The two experiments reported in this article investigated the relations between using worked examples and individual step performance in solving isomorphic problems. In Experiment 1, the effect of worked examples was found for overall performance for novice learners, whereas this effect was gradually reduced from Step 1 (the most difficult one) at which the effect was the strongest, to Step 3 (the easiest one) at which the effect was the weakest or even disappeared. In Experiment 2, relatively more knowledgeable participants learned the same sets of materials, and no effect of worked examples was found for either overall performance or individual step performance. Learner levels of expertise and levels of element interactivity were used to explain the results.  相似文献   

20.
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   

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