首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 500 毫秒
1.
Four experiments with rats tested their ability to anticipate serial patterns made from elements of reward magnitudes (14, 7, 3, 1, or 0 food pellets). Anticipation was measured by the running time in a straight alley. Elements arranged in a monotonically descending pattern were more easily anticipated than were the same elements arranged in a nonmonotonic pattern. Better anticipation was also observed when training utilized four trials per day with short interrun intervals (10–15 sec), spent in the startbox of the runway, than when training utilized one trial per day with long interrun intervals (4–5 min), spent in the rat’s home cage. Anticipation of the monotonie sequence was also superior when training consisted of one trial per day with a short interrun interval relative to that observed with four trials per day and a long interrun interval. Following acquisition of anticipation of the monotonie sequence with a short interrun interval, transfer to the same sequence with a long interrun interval resulted in disruption of anticipation. Finally, anticipation of a well-learned monotonie sequence was not disrupted by replacement of individual rewarded elements in the sequence with a 0-pellet element. These experiments indicate that the duration between runs of a trial, but not that between trials or the number of trials per day, is important in the formation of serial expectancies. They also suggest that the rats come to represent the sequence as items in serial position.  相似文献   

2.
Four groups of rats (n=6 per group) were trained in a runway on a serial learning task. Groups were treated identically in Phase 1, receiving two daily presentations of a five-element series consisting of decreasing numbers of .045-g food pellets over successive runs, for example, 14-7-3-1-0. All groups learned to anticipate, and run slowly to, the terminal 0-pellet element, behavior that has been attributed to learning of a less-than rule, stimulus-stimulus (S-S) associations, and knowledge of the serial position of items. In Phase 2, subjects were transferred to one of four test series: 20-14-7-3-0,20-7-3-14-0, 20-14-7-3-1-0, or 20-7-14-3-1-0. Anticipation was disrupted on the first two series, which maintained the integrity of serial position information and in the first case the less-than rule, but eliminated the terminal portion of the associative chain. Anticipation was unimpaired by transfer to either of the last two series. These series maintained the integrity of the terminal 3-1-0 portion of the associative chain but presented altered information about serial position, and in the last case also altered the less-than rule. The results, which supported the memory-discrimination model of rat serial learning, are discussed with reference to related transfer experiments in human serial learning.  相似文献   

3.
Two groups of five rats each received a decreasing quantity of food reward, 14-7-3-1-0 .045-g food pellets, over successive runs in a runway. The interrun interval (IRI) separating runs within each of two daily pattern repetitions (trials) was 10 sec (short, S) or 4–5 min (long, L) and varied over four successive phases of training in the order indicated by the group names, that is, Groups SLSS and LLLS. Anticipation of the 0-pellet element developed more rapidly in Group SLSS than in Group LLLS, but did eventually occur at the long IRI. Anticipation was eliminated by the increase in IRI experienced by Group SLSS in Phase 2 and by the decrease in IRI experienced by Group LLLS in Phase 4. The results are discussed with reference to the effects of changes in stimulus context accompanying IRI shifts on retrieval of task-specific knowledge and with reference to the possible signal value established to IRI-specific stimuli.  相似文献   

4.
Rats, trained in a runway, were asked to anticipate, while running slowly, the last two events in repeating series of .045-g food pellets. The series were either weakly monotonic (14, 5, 5, 1, and then 0 pellets/run) or nonmonotonic (5-5-14-1-0). While the terminal 0-pellet event was better anticipated in the weakly monotonic series, the reverse was the case for the next-to-last 1-pellet event. These findings were expected from a memory-discrimination learning hypothesis of serial learning, which suggests that the memory of one event in a series can be used to signal the next event. However, the better anticipation of the 1-pellet event by the nonmonotonic group was inconsistent with the recently stated rule-encoding position of Hulse (1980). According to that view, difficult series of the sort employed in the present investigation are learned by encoding the rule structure of the series, with events in the series with the simple rule structure (the weakly monotonic series in this investigation) being better anticipated than events in the series with the complex rule structure.  相似文献   

5.
This experiment determined if rats could extrapolate a familiar serial sequence of diminishing food quantities by accurately anticipating a novel quantity added to the end of the sequence. In 13 days of training, rats ran in a straight runway to obtain quantities of food pellets presented in sequential order. A strongly monotonic group received repetitions of a formally simple pattern of 14-7-3-1 pellets of food, while weakly monotonic and nonmonotonic groups received formally more complex 14-5-5-1 and 14-3-7-1 patterns, respectively. In subsequent transfer, a 0-pellet quantity was added to each pattern, thus extending pattern length to five elements. Results of the very first pattern repetition containing the added 0-pellet element indicated that rats in the strongly monotonic condition, but not in the others, anticipated the reduced quantity before actually experiencing it. This result supports a cognitive, rule-learning hypothesis for serial learning by rats.  相似文献   

6.
Two experiments indicated that two approaches to serial learning are too extreme—the classical view that it consists only of interitem associations and various recent views that it involves no interitem associations. The novel assumption introduced here was that phrasing cues, normally conceptualized as merely segregating long series into smaller units or chunks, may also enter into associations with items, thereby reducing interitem interference and facilitating serial learning. It was found that one item could become a signal for another item, an interitem association, or be overshadowed by a phrasing cue, such as a brightness and temporal cue, also signaling that item. The items were .045-g pellets. Rats traversed a runway for items arranged in ordered series, 14-7-3-1-0 pellets (Experiment 1) or 10-2-0-10 (Experiment 2). Complete tracking of, for example, the 10-2-0-10 series would consist of fastest running to 10 pellets and slowest running to 0 pellets. In both investigations, the interitem association overshadowed was that between 0 pellets and the subsequent rewarded item, 0 → 14 (Experiment 1) or 0 → 10 (Experiment 2). Either repetitions of the 14-7-3-1-0 subpattern (Experiment 1) or merely the terminal 10-pellet item (Experiment 2) were phrased, both methods producing identical results. Overshadowing the 0-pellet item produced superior serial learning, more rapid extinction, and, in Experiment 1, considerable elevation of responding when the brightness phrasing cue was introduced in extinction, an effect said to be conceptually identical to spontaneous recovery and one demonstrating directly that phrasing cues are in reality overshadowing cues. It was suggested that many effects attributed to forgetting may be due to unrecognized overshadowing of memory cues by phrasing cues, giving rise to exaggerated estimates of forgetting.  相似文献   

7.
Hulse and Dorsky found that rats were better able to track (run slowly to) 0 food pellets in a strongly monotonic (decreasing) serial pattern (14-7-3-1-0 food pellets) than in either a weakly monotonic one (14-5-5-1-0) or a nonmonotonic one (14-1-3-7-0). These findings were seen as incompatible with associative approaches based on animal experiments. Instead, they were taken to be consistent with cognitive theories of human behavior that relate pattern difficulty to formally defined structural complexity. In Experiment 1, tracking was found to be poorer with a strongly monotonie series (15-10-5-0) than with either of two weakly monotonic series (15-15-0-0 or 14-14-2-0), and in Experiment 2 a nonmonotonic series (1-29-0) produced better tracking than a strongly monotonic one (20-10-0). Although these results are not necessarily incompatible with the structural complexity view, they do suggest that “element discriminability” is a factor in serial-pattern learning. They are, therefore, compatible with a memory approach that views tracking as a form of discrimination learning.  相似文献   

8.
Squirrel monkeys (Saimiri sciureus) were trained on visual recognition memory tasks in a Wisconsin General Testing Apparatus with a trial-unique procedure that used 250 objects as stimuli. In Experiment 1, acquisition of a trial-unique delayed non-match-to-sample task (DNMS) was compared with acquisition of a trial-unique delayed match-to-sample (DMS) task. The DNMS task was learned in significantly fewer trials and with significantly fewer errors. Two animals in the DNMS group demonstrated highly accurate retention of the DNMS strategy despite an 11-month hiatus in experimental testing. In Experiment 2, the same procedures were used to study the learning of lists of 3, 5, 10, or 20 serially presented items. Although the animals were able to accurately remember lists of up to 20 items, there was no evidence of serial position effects.  相似文献   

9.
Two experiments with rats tested independent predictions from cognitive theories of serial pattern learning. The animals learned to anticipate, as measured by running times in a straight alley, different quantities of food pellets organized into formally defined, five-element serial patterns. In Experiment 1, for some animals the patterns were all formally structured according to a monotonic “less than” relationship in which any quantity was always less than its predecessor. For others, no consistent formal rule was applied. Results of a transfer test with a new pattern showed positive transfer if the formal structure of the new pattern was identical to that used initially, but negative transfer if the new pattern was formally different. In Experiment 2, two groups learned the monotonic patterns 18-10-6-3-1 or 18-10-6-3-0 food pellets, while two others learned the nonmonotonic patterns 18-3-6-10-1 or 10-3-6-10-0 food pellets. We asked if the difference in value of the terminal element, 1 or 0 food pellets, would affect the facility with which the patterns were learned. The results showed that learning rate and the qualitative response to the elements of the monotonie and nonmonotonic patterns were independent of the value of the terminal element. Both experiments lend additional support to the utility of using cognitive models of human serial-pattern learning for an analysis of the sequential behavior of nonhuman animals.  相似文献   

10.
In each of two investigations, rats ran in a runway to obtain varying quantities of food pellets presented in a fixed order, such as 20-0-20. The major finding was that rats ran faster on a 0-pellet trial if that trial was followed shortly by a 20-pellet trial (e.g., 20-0-20 series) than if it was not (e.g., 20-0 series). This finding was obtained both within groups (Experiment 1) and between groups (Experiment 2), and suggested that the memory of 20 pellets arising from the first trial of the 20-0-20 series was retrieved not only on the second trial of the series, thereby signaling 0 pellets, but on the third trial as well, thereby also signaling 20 pellets. Retrieving the memory of 20 pellets on Trial 3 of the 20-0-20 series apparently resulted in that memory’s elevating speed on Trial 2 of that series.  相似文献   

11.
When rats learn to anticipate a sequence of stimulus events, such as a serial pattern of different food quantities, they are sensitive to the rule-based formal structure relating the magnitude of successive stimuli. Earlier research has shown that if formal structure is simple (e.g., if a single “less than” rule relates the size of each successive quantity), patterns are learned faster than if formal structure is complex (e.g., if two or more rules such as “less than” and “greater than” relate successive pattern quantities). Two experiments tested the hypothesis that pattern length modulates the role of pattern complexity. We predicted that pattern length and pattern complexity interact in determining pattern difficulty. That is to say, long complex patterns should be learned more slowly than short complex patterns. However, long simple patterns should be learned faster than short simple patterns. In Experiment 1, rats ran a straight runway to receive repeated sequences of food quantities. The long-monotonic group received a formally simple 18-10-6-3-1-0 pattern, in which each number represents a quantity of food pellets. The long-nonmonotonic group received a formally complex 10-1-3-6-18-0 pattern. Similarly, the short-monotonic and short-nonmonotonic groups received 18-1-0 and 1-18-0 patterns. Pattern tracking—fast and slow running in anticipation of large and small quantities of food, respectively—was taken as an index of pattern learning. In Experiment 2, comparable patterns were used, but rats leverpressed in a discrete-trial procedure; response latencies measured pattern tracking. In both experiments, rats learned formally simple patterns faster than they did formally complex patterns. In Experiments 1 and 2, but less clearly in Experiment 2, the predicted interaction was obtained. The results support and generalize the idea that rats encode and use some representation of the formal rule structure of serial patterns as they learn them.  相似文献   

12.
Three studies tested the notion that rats would treat brain-stimulation reward (BSR) as a stimulus alphabet from which rules could be abstracted to learn serial patterns. In Experiment 1, rats learned to track a serial pattern of 18-10-6-3-1-0 pulses of BSR, responding fast in anticipation of large quantities of BSR and slowly or not at all in anticipation of small quantities of BSR. In Experiment 2, rats learned to track a formally simple 18-6-1-0 pattern faster than a formally complex 18-1-6-0 pattern in a within-subjects procedure, indicating that rats can learn to discriminate between simple and complex pattern structures. Finally, in Experiment 3 rats learned either a formally simple 25-18-10-3-1-0 or a formally complex 25-3-10-18-1-0 pattern whose successive elements were separated by an embedded three-element 6-6-0 subpattern. Rats learned to “chunk together” the dispersed pattern elements, and rats receiving the simple pattern learned to track their pattern, whereas rats receiving the complex pattern did not. The latter results suggest that when simple pattern structure is available, rats can simultaneously track rule structures in at least two memory locations. The results of these experiments, using a new testing procedure and, presumably, a new stimulus alphabet, generalize and extend the idea that rats can abstract relational rules to learn serial patterns.  相似文献   

13.
When rats receive a sequence of rewards of different magnitudes for traversing a runway, they learn to “track” the sequence, showing anticipation of the forthcoming reward by appropriate running speed. There is disagreement as to whether this behavior depends on rats’ encoding and recalling a complete sequence of foregoing hedonic events or just the immediately preceding one. The present experiments showed that rats can remember more hedonic events than the most recent one. In Experiment 1, when exposed concurrently to the sequences 10-1-0 (pellets) and 0-1-10, they were faster on Run 3 of the increasing than of the decreasing sequence, a discrimination which cannot be made on the basis of the preceding (1-pellet) reward alone. Experiment 2 showed that this behavior reflects genuine anticipation of the Run 3 reward, not simultaneous contrast or other simple aftereffects of Runs 1 and 2. It is argued, however, that these results, together with related findings by Capaldi and Verry (1981), show merely that rats can recall a hedonic event other than the most recent one, not that a sequence of such events is fully recalled in order.  相似文献   

14.
Separate groups of rats were trained and tested on asymmetrically and symmetrically reinforced successive delayed matching-to-sample (DMTS) or delayed discrimination (DD) tasks in Experiment 1. Each rat received training and testing on symmetrically reinforced DMTS and DD tasks in Experiment 2. The only difference between each task was that the rats had to respond correctly to a light or tone test stimulus, S2, if it matched a light or tone sample stimulus, S1, in DMTS, but could respond to either S2 if S1 had been a particular stimulus in DD. Only correct leverpresses were reinforced in the asymmetrically reinforced version of each task. Both correct presses and correct omissions were reinforced in the symmetrically reinforced version of each task. Response biases to leverpress during tests for delayed responding to S1 were reduced in both symmetrically reinforced tasks, but only in the DD task did such contingencies produce consistently poorer performance in responding to either S, in Experiment 1. Declines in accuracy of performance that occurred in both experiments were greater to the visual than to the auditory S1 only in the DMTS tasks with increased intervals between S1 and S2. A third experiment, in which rats had to respond to S2 if it matched S1 (DMTS) or if S2 mismatched S, (DMmTS), was carried out. Modality of S1 similarly affected accuracy of delayed responding in each task, as in the first two experiments. Methodological and theoretical implications of these results are discussed in terms of Honig and Thompson’s (1982) dual-process theory of working memory.  相似文献   

15.
In Experiment 1, two groups of female rats were trained in a triangular pool to find a hidden platform whose location was defined in terms of a single a landmark, a cylinder outside the pool. For one group, the landmark had only a single pattern (i.e., it looked the same when approached from any direction), while for the other, the landmark contained four different patterns (i.e., it looked different when approached from different directions). The first group learned to swim to the platform more rapidly than the second. Experiment 2 confirmed this difference when female rats were trained in a circular pool but found that male rats learned equally rapidly (and as rapidly as females trained with the single-pattern landmark) with both landmarks. This second finding was confirmed in Experiment 3. Finally, in Experiment 4a and 4b, male and female rats were trained either with the same, single-pattern landmark on all trials or with a different landmark each day. Males learned equally rapidly (and as rapidly as females trained with the unchanged landmark) whether the landmark changed or not. We conclude that male and female rats learn rather different things about the landmark that signals the location of the platform.  相似文献   

16.
In Experiment 1, rats received escape training in which an exteroceptive feedback cue occurred in the safe box, and safe-box confinement durations of 5 or 20 sec were combined orthogonally with shock-box confinement durations of 5 or 20 sec. Exteroceptive feedback reliably facilitated escape performance relative to no-feedback controls when safe-box confinement was relatively longer than shock-box confinement. Confinement duration also facilitated performance in the absence of exteroceptive feedback. In Experiment 2, escape training with or without feedback was followed by extinction either with the feedback condition of prior training or with the opposite feedback condition. Feedback presentations in extinction reliably increased responding. Feedback removal reliably decreased responding relative to feedback controls. Introduction of feedback in extinction reliably enhanced performance relative to no-feedback controls.  相似文献   

17.
According to the mixed memory model (Penney, Gibbon, & Meck, Journal of Experimental Psychology: Human Perception and Performance, 26, 1770–1787, 2000), different clock rates for stimuli with different nontemporal properties must be stored within a single reference memory distribution in order to detect a difference between the clock rates of the different signals. In Experiment 1, pigeons were trained in a between-subjects design to discriminate empty intervals (bound by two 1-s visual markers) and filled intervals (a continuous visual signal). The intervals were signaled by different visual stimuli, and they required responses to different sets of comparison stimuli. Empty intervals were judged as being longer than filled intervals. The difference between the point of subjective equality (PSE) for the empty intervals and the PSE for the filled intervals increased proportionally as the magnitudes of the anchor duration pairs were increased from 2 and 8 s to 4 and 16 s. In Experiment 2, the pigeons were trained to discriminate intervals signaled by the absence of houselight illumination (Group Empty) or the presence of houselight illumination (Group Filled). The psychophysical timing functions for these intervals were identical to each other. The results of Experiment 1 indicate that memory mixing is not necessary for detecting a timing difference between empty and filled intervals in pigeons. The results of Experiment 2 suggest that the nature of the stimuli that signal the empty and filled intervals impacts how pigeons judge the durations of empty and filled intervals.  相似文献   

18.
In these experiments, each rat received two different series of three runs each. The lone group in Experiment 1 received the series 10-0-10 and 10-0-0, where, for example, 10-0-10 means that the rat received three discrete runs (in a runway) that terminated in 10, 0, and 10 pellets, respectively. In Experiment 2, the series were 20-0-0 and 0-0-20 for one group and 20-0-20 and 0-0-0 for another. Of primary concern in both experiments was the rat’s anticipation, as measured by running speed, of 0 pellets on the middle, or second, run of each series. In each experiment, running speed to this 0-pellet event was independent of reinforcement magnitude on the first run of each series and was greater, the greater the reinforcement magnitude on the third run of each series. These results indicate that on the second run of each series the rat was anticipating not merely the 0 pellets associated with that run (intraevent anticipation), but also the reinforcement magnitude associated with the future, third run of each series (interevent anticipation). These results are shown to be consistent with an S-S cognitive view of anticipation and inconsistent with an S-R serial-chaining view of serial learning.  相似文献   

19.
In each of three serial learning investigations, rats in a runway were given varying numbers of 0.045-g food pellets in a fixed order. Serial learning was indexed by faster running to larger than to smaller reward quantities. It has been suggested by Hulse (Animal Learning & Behavior, 1980,8, 689–690) and by Roitblat (Behavioral Brain Sciences, 1982,5, 353–371) that differences between two or more serial learning groups that have been obtained under one set of specified experimental conditions may be completely reversed or eliminated under another set of specified experimental conditions. In each of the three investigations reported here, we examined series that had been compared in previous investigations, employing, however, experimental conditions that, according to Hulse and to Roitblat, should produce results different from those obtained previously. In each of the three investigations reported here, the groups differed as they had previously. The findings obtained in this report suggest that none of the following variables is critical to the results obtained in serial learning investigation in the sense suggested by Hulse and Roitblat: the number of items contained in the series, the number of times the series is presented each day, the temporal interval elapsing between items, and the temporal interval elapsing between series presentations. The implications of the present findings for the rule-encoding view of Hulse and his coworkers and for the memory-discrimination learning view of Capaldi and his coworkers are examined.  相似文献   

20.
Two experiments investigating odor production and utilization in rats under the effects of Thorazine and Elavil injections, respectively, are reported. In Experiment 1, significantly slower speeds shown by the Thorazine-injected subjects indicated that this drug depressed performance. It is felt that depressed performance allowed these subjects to attend and respond to odor cues earlier in Phase 1 than did saline-injected control animals. Reversing the injection conditions (Phase 2) failed to disrupt already-established patterning. During the first phase of Experiment 2, Elavil-injected subjects failed to establish patterned responding, whereas such responding was readily established by saline-injected subjects. Reversing the injection conditions (Phase 2) resulted in the rapid development of double-alternation patterning by the subjects that were shifted from Elavil to saline and in the maintenance of such responding by the animals shifted from saline to Elavil.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号