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1.
We investigated the effect of associating unique contextual cues with an interpolated learning task on retroactive interference in long-term memory. Rats were originally trained in a two-bar operant chamber with an auditory conditional discrimination stimulus. During interpolated learning, which occurred in either the original or a new context, some rats were trained on a probability learning task that did not include the auditory stimuli present during original learning. Subsequent retraining on the original conditional discrimination task in the original context showed that (1) significant retroactive interference occurs in rats, and (2) the presence of unique contextual cues during interpolated learning significantly reduces this interference. These results extend the conditions under which the susceptibility to retroactive interference can be altered by contextual cues. 相似文献
2.
Robert D. Tarte 《Learning & behavior》1974,2(4):289-292
In two experiments, hungry rats received four extinction sessions in the presence of free food. When the free food was removed for eight subsequent extinction sessions, the animals made significantly fewer responses than did control groups which received no intervening sessions. The results are contrary to those of Enkema et al (1972). From the results of additional groups of rats which received four intervening sessions of free food only, empty chamber, or time in home cage, it was concluded that the presence of free food caused the diminution in extinction responding. 相似文献
3.
Many characteristics of a series of discrete independent hedonic events may be remembered by rats in terms of, for example, how many events were rewarded and how many were nonre-warded. Such memory for multiple hedonic events, which has been shown to be a potent factor controlling instrumental responding, was examined here in five investigations employing serial anticipation learning in a runway. It was found that the ability of rats to remember the hedonic events reward and nonreward is highly developed, accurate, and quite resistant to forgetting and interference. Rats not only remembered a rewarded event and a nonrewarded event, but they also remembered the order in which the two events occurred. Rats remembered how many nonrewarded events there had been accurately enough to suggest that they were using some form of a counting mechanism. Rats exhibited little forgetting of eight prior discrete hedonic events, one rewarded followed by seven nonrewarded, even when these occurred over an interval of 20 min and involved considerable potential interference. In the serial learning situation employed here, marked primacy effects were obtained, earlier nonrewarded trials in a series being better anticipated than later ones. The primacy effect was found to depend upon the type of series employed. By assuming that stimulus generalizations occur between the multiple hedonic events remembered by rats, all anticipatory learning obtained here could be explained in considerable detail. 相似文献
4.
Rats were exposed to an autoshaping procedure in which each lever-contact or leverpress delayed trial offset and, hence, food delivery. Yoked subjects received identical trial-food pairings as did delay subjects. This procedure was studied at two delay values (2.5 and 10.0 sec) in experimentally naive rats and those which had previously received 25 sessions of autoshaping. The delay procedure retarded the acquisition of autoshaped responding in naive subjects and reduced responding for experienced subjects. Yoked subjects responded at higher levels than did delay subjects throughout training. 相似文献
5.
Rats are typically less accurate in their arm selections in the radial maze over successive trials in a session (Roberts & Dale, 1981). In the present study, rats’ choice accuracy declined when such trials were separated by 2-min (massed) but not by 2-h (spaced) intertriai intervals. Changing intramaze visual/tactile arm stimuli (Experiments 1 and 3) or extramaze landmark stimuli (Experiment 4) between trials weakened the massed-trials effect, but changing the number of food pellets per arm, either alone or in conjunction with changes in intramaze cues (Experiments 2 and 3), did not. The rats also tended to avoid the spatial locations of their last four choices on a previous trial during their first four choices on a current trial, and more so with massed than with spaced trials. These findings indicate that intertriai proactive interference (PI) occurred only with massed trials and was weakened by changing intra- and extramaze cues between such trials. 相似文献
6.
David Chiszar Santford Wellborn Mary Ann Wand Kent M. Scudder Hobart M. Smith 《Learning & behavior》1980,8(3):505-510
In Experiment 1, boid and colubrid snakes defecated with shorter latencies after their home cages were cleaned than did control snakes that received equivalent handling without cage cleaning. Experiment 2 replicated this finding and also showed that snakes exposed to clean cages emit more tongue flicks after reintroduction to the clean home cage than do control snakes. Experiment 3 demonstrated that cage cleaning has similar effects in two species of crotalid snakes. The increase in tongue flicking after cage cleaning is interpreted as investigatory behavior and reflects the fact that snakes respond to the absence of familiar odors. Experiment 4 showed that a clean cage containing odors derived from snake feces produces less tone-flick exploration and fewer defecation responses in rattlesnakes than does a clean cage without such odors. 相似文献
7.
In a conditioned suppression experiment, rats received a single, massed session of conditioning in which one backward conditioned inhibitory stimulus (CS-) followed shocks that were signaled by a visual cue, and a second backward CS-followed shocks that were unsignaled. Conditioning was preceded by a preexposure phase in which some groups of rats were preexposed to unsignaled shock, while others were not preexposed and remained in the experimental apparatus in the absence of shock. The groups were further distinguished by whether US preexposure and conditioning occurred in the same or different contexts, and by whether conditioning began immediately or after a 24-h rest period in the home cage. Although the conditioning itself was effective in establishing the visual cue as a conditioned excitor in the nonpreexposed groups, it was not effective in establishing the two backward cues as reliable inhibitors with either signaled or unsignaled USs. After 210 US preexposures, however, the same conditioning sessions did yield conditioned inhibition to both CS-s. A 24-h rest period in the home cage reduced the magnitude of, but did not completely abolish, the facilitative effect of US preexposure on inhibitory conditioning. Other tests demonstrated that US preexposure had retarded excitatory conditioning to the visual cue. This interference with excitatory conditioning was unchanged in magnitude after the 24-h rest period. The facilitative effect of US preexposure on backward inhibitory conditioning, and the interference effect on excitatory conditioning, were both eliminated by a change in context between US preexposure and conditioning. These observations encourage predominantly associative accounts of the effects, but allow for a small nonassociative habituation component. 相似文献
8.
William A. Roberts 《Learning & behavior》1991,19(4):305-316
A four-arm radial maze containing 10 feeders in each arm (patch) was used to study patch sampling in rats. In each of three experiments, rats foraged for 30 sessions. On each session, two randomly chosen patches were baited with food and the remaining two patches were empty. In Experiment 1, the number of baited feeders in baited patches (6) was varied from 1–10 over five groups of subjects. Mean visits to empty patches was an inverse function of 6, as predicted by an optimal foraging model. In Experiments 2 and 3, rats’ ability to discriminate between baited and empty patches was examined when food in baited patches was placed in fixed locations, either in clumps (Experiment 2) or distributed throughout the patch (Experiment 3). Rats in fixed-food-location conditions reliably visited fewer feeders in empty patches than did rats in randomly changing control groups. Examination of within-patch foraging patterns indicated that rats in fixed-food-location groups selectively sampled potentially baited locations and abandoned the patch if food was not found. It is suggested that processes of patch discrimination were responsible for these effects. 相似文献
9.
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
10.
David Chiszar Santford Wellborn Mary Ann Wand Kent M. Scudder Hobart M. Smith 《Learning & behavior》1980,8(3):511-511
In Experiment 1, boid and colubrid snakes defecated with shorter latencies after their home cages were cleaned than did control snakes that received equivalent handling without cage cleaning. Experiment 2 replicated this finding and also showed that snakes exposed to clean cages emit more tongue flicks after reintroduction to the clean home cage than do control snakes. Experiment 3 demonstrated that cage cleaning has similar effects in two species of crotalid snakes. The increase in tongue flicking after cage cleaning is interpreted as investigatory behavior and reflects the fact that snakes respond to the absence of familiar odors. Experiment 4 showed that a clean cage containing odors derived from snake feces produces less tone-flick exploration and fewer defecation responses in rattlesnakes than does a clean cage without such odors. 相似文献
11.
Robert Ader 《Learning & behavior》1975,3(4):337-339
Beginning at 21 days of age, rats were housed 10 per cage in a competitive environment (a large cage containing a single food and water source) or a noncompetitive environment (a large cage containing multiple food and water sources). At maturity, matched pairs of animals from within a single rearing cage were tested for shock-elicited fighting over five 100-trial sessions. In each of two experiments, animals reared in the noncompetitive environment displayed more aggressive behavior than animals reared in the competitive environment. 相似文献
12.
Rats were exposed for approximately 1 month to a single stimulus mounted on the home cage wall. During discrimination training, half of the Ss had the exposed figure as the positive stimulus and half the exposed figure as the negative stimulus. Control Ss had no pattern mounted on the wall. The results indicate that when the exposed figure was the positive stimulus, the Ss made significantly more errors than the control Ss. but when the exposed figure was the negative stimulus, the Ss made significantly fewer errors. These results are consistent with the exploratory literature, which suggests that exposure to a stimulus will reduce the invitational properties of that stimulus relative to a more novel stimulus and thereby will affect the probability of selecting one stimulus over another, at least for a period of time, in a discrimination task. 相似文献
13.
Alfred V. Bacotti 《Learning & behavior》1976,4(1):41-44
Eleven rats were exposed to a multiple variable-interval 1-min variable-interval 1-min schedule of reinforcement. All rats were initially fed a daily ration of food in the home cages immediately after the end of each session. In a later phase of the experiment, the same amount of food was fed 1 h after the end of each session. Later, five rats were again fed immediately after each session. Amount of food received and deprivation level in terms of percent of free feeding weight were constant across conditions. Response rates decreased within each session under immediate feeding. When feeding was delayed, rates in each component of the multiple schedule increased throughout the session and the decreasing trends were generally eliminated. The results suggest that home cage feeding time, apart from changes in deprivational level, is an important variable in the control of behavior in experimental sessions. 相似文献
14.
Rats were trained on an interval time-place learning (TPL) task in which the location of food availability depended on the
time since the start of the session. Each of four levers (numbered 1, 2, 3, 4) provided food on an intermittent schedule for
two nonconsecutive 3-min periods. The order in which the levers provided food was 1, 2, 4, 3, 2, 3, 1, 4. This order was consistent
across sessions. Previous research conducted in our lab has shown that when only four “places” are used, rather than the eight
in the present study, rats use a timing strategy to track the location of food. Pizzo and Crystal (2004) recently trained
rats on an interval TPL in which each of eight arms of a radial arm maze provided food. They found evidence suggesting that
rats used both spatial and temporal information. In the present study, in which a revisiting strategy was used (i.e., each
lever provided food on more than one occasion), the rats tracked both the spatial and the temporal availability of food for
the first half of the session. Interestingly, in the second half of the sessions, the rats appeared to be timing the availability
of food even though they did not know where it would occur. That is, the rats knew the temporal, but not the spatial, contingencies
for the second half of the session. It appears that the requirement of revisiting a previously reinforced lever resulted in
rats' no longer being able to solve the spatial aspect of the task. 相似文献
15.
Rats found food in a rectangular enclosure in three experiments testing how learning about a distinctive feature near a goal
interacts with learning based on the geometry of an enclosure. Rats trained to follow a feature in square and triangular enclosures
and to use geometry in the rectangle followed the feature when it was in the rectangle (Experiment 1). Rats trained with the
feature in a geometrically consistent corner of the rectangle learned about both geometry and the feature (Experiment 2).
Training with the feature in the square did not block learning of geometry when both predicted the location of food in the
rectangle (Experiment 3). The “geometric module” (Cheng, 1986) may have a special status in spatial learning. 相似文献
16.
In previous research designed to test whether place learning or response learning proceeds more quickly and better in rats,place has not been defined unambiguously when direction has been controlled by moving an apparatus around in the test room (Blodgett,
McCutchan, & Mathews, 1949; Skinner et al., 2003). In Experiment 1, we compared place and response learning while controlling
direction in a static apparatus, thus making the meaning of place unambiguous. The performance of rats that had to make different
turns to find food in a particular place and rats that had to always make the same turn to find food in two different places
did not differ. In Experiment 2, visual cues were made equally discriminable for place and response learners in a static apparatus.
Place learners still failed to outperform response learners, but there was evidence that response biases interfered more with
place than with response learning. The results are discussed with reference to the historical debate that generated the original
research and also in terms of more contemporary spatial-learning issues in rats. 相似文献
17.
Phil Reed 《Learning & behavior》2016,44(1):78-84
An experiment examined the impact of a procedure designed to prevent response or extinction strain occurring on random interval schedules with a linear feedback loop (i.e., an RI+ schedule). Rats lever-pressed for food reinforcement on either a RI+ or a random interval (RI) schedule that was matched to the RI+ schedule in terms of reinforcement rate. Two groups of rats responded on an RI+ and two on an RI schedule matched for rate of reinforcement. One group on each schedule also received response-independent food if there had been no response for 60 s, and response-independent food continued to be delivered on an RT-60 schedule until a response was made. Rats on the RI and RI+ obtained similar rates of reinforcement and had similar reinforced inter-response times to one another. On the schedules without response-independent food, rats had similar rates of response to one another. However, while the delivery of response-independent food reduced rates of response on an RI schedule, they enhanced response rates on an RI+ schedule. These results suggest that rats can display sensitivity to the molar aspects of the free-operant contingency, when procedures are implemented to reduce the impact of factors such as extinction-strain. 相似文献
18.
Rats were used to examine the extent to which extinction of an acquired conditioned taste aversion retards subsequent reacquisition. A saccharin-flavored solution (sac) was paired with LiCl and then followed by CS-alone extinction trials with this flavor. A control group received a different flavor, decaffeinated-coffee (coff), during initial conditioning and extinction. Sac was then paired with LiCl for all rats during a second conditioning phase. Reacquisition of the aversion to sac was retarded relative to the acquisition of an aversion to sac by the control group. A similar experiment with fewer extinction trials, but still with complete loss of the initial aversion, did not obtain slow reacquisition. The results are discussed with respect to an interference view of extinction and the slow-reacquisition effect. 相似文献
19.
Rats trained to push a joystick to the left or right for food reward were given two successive tests in which neither response was reinforced. Prior to Test 1, subjects were either confined in the apparatus with a passive conspecific (Group None), or allowed to observe a conspecific demonstrator making 50 nonreinforced responses in the direction that had beeirrewarded during observer training (Group Same) or in the opposite direction (Group Different). In Test 1, Group Same made fewer previously reinforced responses than did Group Different, which made fewer than Group None, and Groups Same and Different each made fewer previously nonreinforced responses than did Group None. In Test 2, Group Same made fewer previously reinforced responses than did Group None. These results indicate that observation of nonreinforced responding can reduce resistance to extinction (Test 1) and spontaneous recovery (Test 2) in rats. 相似文献
20.
Hooded rats and golden hamsters were shocked by one of two prods in a chamber with a sawdust-covered floor. Rats buried the prod through which they had been shocked, but hamsters displayed no burying behavior. Hamsters may not have buried the prod because they could not perform the required motor pattern. However, hamsters can carry and pile food pellets. Therefore, in a second experiment, rats and hamsters were shocked in a chamber with wooden blocks on the floor. Rats piled blocks around the prod through which they had been shocked, but hamsters did not. The third experiment established that, like rats, hamsters can associate a prod with shock in one trial, since they showed differential avoidance of a prod through which they had been shocked. Since hamsters are nonsocial and rats are social, these results are consistent with suggestions that burying sources of aversive stimulation evolved as an altruistic behavior. 相似文献