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1.
In four experiments using rat subjects, we investigated the effects of presenting a novel flavor cue at the time of pairing an environmental context with illness. In each experiment, the subjects were allowed to spend time in a distinctive cage before receiving an injection of LiCl. For some, plain water was made available on these conditioning trials; for others, a novel taste (HCl) was presented. We measured the strength of the context aversion by assessing the ability of the contextual cues to block the acquisition of an aversion to sucrose in a further phase of training. We found that initial training with HCl present made the context less effective as a blocking cue and concluded that the HCl had overshadowed learning about the context. We suggest that this blocking procedure provides a more accurate assessment of contextual aversion than does the consumption test that has more usually been used and that taste-context overshadowing may be a more robust phenomenon than has thus far been thought. 相似文献
2.
The relationship between absolute and relative stimulus novelty was examined within the context of the conditioned taste aversion paradigm in which the relative novelty of the conditioned interoceptive stimulus was manipulated by differential exteroceptive context habituation. Rats received similar isolation histories but either 5 or 30 days of habituation to the test environment prior to treatment. One group was administered lithium chloride following saccharin consumption, a second group was administered isotonic saline following saccharin consumption, and a third group was administered saline after water consumption. The animals habituated for 30 days exhibited greater conditioned avoidance and greater neophobic avoidance of saccharin than did animals habituated for only 5 days. The results are interpreted in terms of a cross-modality stimulus contrast effect which implicates context habituation as an important parameter of both taste neophobia and taste aversion learning. 相似文献
3.
Julia Wallace Pamela A. Steinert Stanley R. Scobie Norman E. Spear 《Learning & behavior》1980,8(1):10-16
Two experimental paradigms are presented aimed at determining the retention of auditory and visual information over brief delay intervals. First, a conditional delayed matching-to-sample procedure was used in which rats were required to symbolically match the modality of the sample stimulus with one of two comparison stimuli. In the second experiment, subjects were trained and tested using a Konorski-type procedure. Despite the conceptual and procedural differences between the two procedures, subjects in both experiments showed steeper forgetting functions for visual events than for auditory events, while performance levels at 0-sec delay intervals were equivalent for both stimuli. These results, when taken together with related research conducted with pigeons, suggest that content of memory may have important influences on the short-term retention abilities of animal subjects. 相似文献
4.
A series of experiments was conducted to examine the phenomenon of potentiation. Experiment 1 demonstrated potentiation of odor aversions by taste when morphine served as the unconditioned stimulus (US). Experiment 2 provided evidence that the observed potentiation was due to a within-event association between odor and taste stimuli, rather than reflecting an enhanced odor-morphine association. In Experiment 3, morphine supported place conditioning to contextual cues and aversive conditioning to a taste cue, but potentiation of place conditioning by a taste cue was not obtained. Apparently the absence of potentiation was due to the dual nature of the morphine US, as potentiation of a contextual aversion by taste was obtained in Experiment 4 when a strictly aversive US (lithium) was used. These data suggest that potentiation depends on (1) an initially weak association between the to-be-potentiated conditioned stimulus (CS) element and the US, and (2) the elicitation of qualitatively similar responses by the individual elements of the CS compound. Collectively, these results support an explanation of potentiation based on within-event learning. 相似文献
5.
In this study, we investigated the separability of novelty from specific stimulus characteristics (e.g., color or taste quality) in the transfer of aversion effects. Ninety-six chicks (Gallus domesticus) received a novel visual (red water) or taste (3.0% vinegar) CS paired with an injection of lithium chloride or saline. The chicks were then tested for aversion to the CS or for conditioning-enhanced neophobia in response to a different novel visual cue (green water) or taste cue (1.0% saline). Aversions to the CSs were reliable and similar to each other. Reliable evidence of conditioning-enhanced neophobia occurred with respect to each test stimulus, irrespective of the type of CS, but conditioning with the vinegar CS produced reliably greater enhancement of neophobia than did conditioning with red water. For each CS, postconditioning neophobia was more persistent in testing with saline than with green water. The results for postconditioning neophobia suggested that novelty is a general stimulus property that is separable from specific stimulus characteristics. 相似文献
6.
《Contemporary educational psychology》1988,13(2):102-115
Two experiments examined the effects of visual and auditory modes of input on long-term memory. In Experiment 1, 40 subjects learned a 40-word list presented in a blocked or random fashion. In the blocked conditions learners were presented half the nouns in one modality followed by the remaining 20 words in the other modality (See-Hear or Hear-See). Subjects in random conditions also received half the list in each modality, but the presentation was random (Mixed or Mixed Reverse). Following a 6-min delay, subjects completed an 80-item visual recognition test. Analysis of these data showed significantly (p < .05) greater recognition of words presented visually than those presented auditorily. Experiment 2 was designed to test the hypothesis that learners may visualize a “literal copy” of the stimulus item by controlling for the extent to which the recognition measure offered a visual cue. Two groups of 40 subjects were examined using the same procedure used in Experiment 1, with the exception that one group received a visual recognition test while the other was tested auditorily. These data showed that the lack of a visual cue hindered the recognition of visually presented words, while it had little effect on stimuli presented auditorily. The results of these experiments were interpreted as support for the hypothesis that physical characteristics of a stimulus may persist in memory well beyond immediate memory intervals. Subjects were seen to make modality-specific decisions by testing long-term memory for the presence or absence of a visual memory trace. 相似文献
7.
In a Pavlovian conditioning situation, an initially neutral stimulus may be made excitatory by nonreinforced presentations
in compound with an established conditioned excitor [i.e., second-order conditioning (SOC)]. The established excitor may be
either a punctate cue or the training context. In four conditioned suppression experiments using rats, we investigated whether
SOC phenomena parallel other cue interaction effects. In Experiment 1, we found that the response potential of a target stimulus
was directly related to the intertrial interval when SOC was mediated by a punctate cue, and inversely related to the intertrial
interval when SOC was mediated by the training context. Experiment 2 demonstrated that punctate- and context-mediated SOC
are oppositely affected by posttraining context extinction, and Experiments 3 and 4 demonstrated that context- and punctate-mediated
SOC are differentially affected by conditioned stimulus (Experiment 3) and unconditioned stimulus (Experiment 4) preexposure
treatments. These findings parallel phenomena in conditioned inhibition and cue competition situations. 相似文献
8.
Four experiments examined the influence of a stimulus presented after one response in a two-lever choice task. In Experiment 1, food-deprived rats trained on a concurrent variable-interval extinction schedule responded more often on the extinction lever when such responding periodically produced a visual stimulus than when it did not. In Experiments 2 and 3, a similar signal-induced enhancement effect was found even when food was delivered randomly with respect to responding on both levers or when no food was presented. In Experiment 4, a response-contingent visual stimulus elevated responding to the lever on which it was presented, but an auditory cue suppressed responding. These findings indicate that visual stimuli may possess intrinsically reinforcing properties for rats. 相似文献
9.
In delayed matching-to-sample with pigeons, brief postsample cues signaled different trial outcomes. The normal comparison stimuli followed the cue to remember (R cue). In the comparison-omission procedure, comparison stimuli and reinforcement were omitted following the cue to forget (F cue). In the comparison-substitution procedure, comparison stimuli were replaced by a single stimulus and reinforcement for a single response following the F cue. Infrequent probe trials revealed that F cues disrupted matching, with the amount of accuracy loss dependent on the length of the cue-comparison delay. These results, however, were found only with the comparison-omission procedure (Experiment 1). Replacing the comparison stimuli with another simultaneous (unconditional) discrimination revealed no accuracy loss in F-cue probes (Experiment 2), even though choice latencies were again lengthened by F cues. These results suggest that, while the F cue interferes with performance at the time of a retention test by slowing choices, it also interferes with sample retention. Alternative models of the cuing effect and its apparent dependence on end-of-trial reward are outlined. 相似文献
10.
Although taste memory has been extensively studied within the context of long-delay taste aversion learning, little attention has been devoted to taste memory within more traditional memory designs, for example, simple delayed discriminations. This was examined in the present experiment. Specifically, following taste discrimination training during which responding was reinforced following exposure to only one of two tastes, delays were imposed between sampling of the initial taste and the opportunity to respond. On the average, subjects were able to perform the simple delayed taste discrimination with an accuracy of 80% or better at a delay of 45 sec. Discrimination performance returned to chance at an average delay of 58 sec. Taste memory within the simple delayed discrimination paradigm is discussed and compared with other assessments of short-term memory in the rat and other species. 相似文献
11.
In the present study, we examined whether the presentation of postevent cues would bias recognition in a visual delayed matching-to-sample task with pigeons. Postevent cues were either consistent with the original target stimulus (i.e., they were the same as the correct choice option at recognition), inconsistent (i.e., they were the same as the incorrect recognition option), or neutral (i.e., they were different from both the correct and the incorrect recognition options). In Experiment 1, a single colored light served as the target stimulus. In Experiment 2, the target stimulus was one of three lights presented in a sequence. Both experiments demonstrated that recognition choices were biased toward the option corresponding to the postevent cue, but only if the cue occurred at the end of the delay interval. The present results mirror those found using the misinformation paradigm with human subjects. 相似文献
12.
Nonreinforced exposure to a nontarget stimulus that was followed by nonreinforced exposure to a target/nontarget simultaneous
compound stimulus resulted in enhanced latent inhibition of the target. Conditioning was slower after this treatment than
after nonreinforced exposure to the target stimulus alone (Experiment 1). However, a salient auditory stimulus presented immediately
after the compound in the second phase reduced levels of latent inhibition, relative to the enhanced latent inhibition produced
when no such extracompound stimulus was presented (Experiments 2 and 3). This effect was not noted if the salient auditory
cue was presented 10 sec after the termination of the compound stimulus (Experiment 4). In Experiment 5, there was no disruption
of simple latent inhibition produced by a salient stimulus. These results are consistent with enhanced latent inhibition’s
being produced by the formation of within-compound associations, which are disrupted by the salient extracompound stimuli. 相似文献
13.
Douglas C. Brooks Matthew I. Palmatier Eliseo O. Garcia Jessica L. Johnson 《Learning & behavior》1999,27(1):77-88
The effect of an auditory cue presented during extinction on spontaneous recovery of a conditioned taste aversion was investigated in three experiments. Experiment 1 demonstrated that the presence of the cue during extinction did not influence saccharin consumption during that phase, and that an aversion to saccharin in the absence of the cue was stronger at 18 days than at 1 day after extinction, representing spontaneous recovery rather than a renewal effect. Experiment 2 showed that a cue presented during extinction and testing reduced spontaneous recovery. Experiment 3 replicated that effect and showed that it depended on the cue’s correlation with extinction and not on an unconditioned effect; cues that had been presented during or prior to conditioning did not reduce spontaneous recovery when presented during testing. The cue’s potential to reduce spontaneous recovery through conditioned inhibition or configural cue learning is discussed, as is the possibility that the cue retrieves a saccharin extinction memory in a manner consistent with Bouton’s (1993) account of spontaneous recovery. 相似文献
14.
Geoffrey Hall 《Learning & behavior》1980,8(2):282-286
Two experiments demonstrated that pigeons can solve a simultaneous discrimination in which on half the trials the positive and an ambiguous cue (A) are presented and on half the trials choice is between A and the negative stimulus. In Experiment 1, where a relatively nondistinctive A cue was used, performance on the former type of trial was superior to that shown on the latter. In Experiment 2, where a distinctive A cue was provided, this pattern of results was reversed. These findings are interpreted in terms of an approach-avoidance explanation first proposed by Leary (1958). Experiment 3 tested and confirmed a central prediction of this explanation by showing that in an orthodox simultaneous discrimination, occasional reinforcements of the negative stimulus produce less accurate performance than do nonreinforcements of the positive. 相似文献
15.
The ability of visual CSs previously paired with flavored substances to substitute for those substances as conditional discriminative cues was examined in two Pavlovian appetitive conditioning experiments using rat subjects. In Experiment 1, a visual stimulus was first paired with the delivery of a sucrose solution. Then the rats were trained in conditional discrimination tasks in which sucrose delivery alone served as a conditional cue signaling whether or not a subsequent tone would be reinforced with food pellets. Subjects rapidly acquired discriminative performance to the tones, especially in a feature-negative condition in which sucrose delivery signaled when the tone would not be reinforced. In a subsequent test in which neither food nor sucrose was delivered, presentation of the visual CS also controlled discriminative performance to subsequently presented tones. Experiment 2 showed the ability of a visual CS to substitute for a flavored substance as a conditional cue to be highly stimulus specific. Experiment 2 also showed that a flavored substance was less effective as a conditional cue when it was made to be expected by preceding it with a previously associated visual signal than when it was made to be surprising by preceding it with a visual stimulus signaling another flavored liquid. These results indicate that CS-evoked representations of events can substitute for those events themselves in the control of previously established conditional discrimination performance. 相似文献
16.
Rescorla RA 《Learning & behavior》2008,36(2):67-74
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
17.
In two experiments, rats were presented with a taste conditioned stimulus (CS) alone, an odor CS alone, or an odor-taste compound followed by lithium chloride injection. When tested 1 day following conditioning, there was evidence that the odor cue overshadowed conditioning to the taste; however, there was no indication of overshadowing following a longer (21-day) retention interval, despite undiminished strength of the aversion in animals conditioned with only the single element (taste). The overshadowing observed at the 1-day retention interval was not reciprocal. Rats conditioned with the odor CS alone or with the compound CS expressed odor aversions of comparable strength—that is, no overshadowing. However, in contrast to the taste aversion, overshadowing of conditioning to the odor by taste was evident following a 21-day retention interval. Rather than reflecting a failure of the overshadowed stimulus to acquire associative strength, these data suggest that overshadowing may be expressed, or not expressed, as a result of changes in the relative retrievability of learned associations over time. 相似文献
18.
Rats exposed for 60 sec to a flashing light stimulus following one-trial fear conditioning showed enhanced retention performance relative to controls not exposed to the flashing light. The results of a second experiment demonstrated a time-dependent gradient of the enhancement effect. In view of additional data indicating that the flashing light is not aversive, these results suggest that the presentation of an exteroceptive stimulus can influence memory processing. 相似文献
19.
In Experiment 1, olfactory bulbectomized and control rats were trained using operant conditioning to determine the taste threshold of aqueous amyl acetate. Concentrations below gustatory threshold were used in Experiments 2–5 to compare the effectiveness of odors with various concentrations of saccharin as cues for illness. The results showed the following: (1) The effectiveness of odor and taste was directly related to concentration; (2) the strength of an aversion to a concentration of taste could be matched by an appropriate concentration of an odor; (3) odor was as effective as taste with CS-US delays of 4 h; and (4) an effective odor potentiated an aversion to an otherwise ineffective taste. The results challenge the privileged role accorded tastes in food aversion learning and the manner in which tastes are held to interact with odors according to the sensory-and-gate channeling analysis of potentiation (Rusiniak, Hankins, Garcia, & Brett, 1979). 相似文献
20.
Angelo Santi 《Learning & behavior》1989,17(3):349-354
Pigeons were trained in a two-choice delayed matching-to-sample task with red and green hues. A brief postsample cue (a vertical or horizontal line) signaled whether the comparison stimuli would be presented or omitted on each trial. Comparison stimuli were always presented following the remember (R) cue, but never following the forget (F) cue or no-cue trials. One group of birds, the differential outcome (DO) group, received reinforcement with a probability of 1.0 for correct responses following one sample stimulus and a probability of 0.2 for correct responses following the other sample stimulus. The nondifferential outcome (NDO) group received reinforcement with a probability of 0.6 for correct responses to either stimulus. The effect of postsample cues was greater for the DO group than for the NDO group. Relative to the NDO group, the DO group displayed higher accuracy on R-cue trials and lower accuracy on F- and no-cue trials. Both tendencies contributed to the enhanced cue effectiveness obtained in the DO group. The results indicate that outcome expectancies are subject to maintenance rehearsal, which comes under the control of postsample R and F cues. They also suggest that maintenance rehearsal may be easier to sustain under DO conditions than under NDO conditions when a memory test is anticipated, but that it may be easier to terminate maintenance rehearsal under DO conditions when a memory test is not anticipated. The results are inconsistent with the assumption that the rehearsal of outcome expectancies is automatic. 相似文献