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 0 毫秒
1.
Experiment 1 compared the responses of 10 laboratory-reared and 10 wild-reared rhesus monkeys (Macaca mulatta) to a real snake and to a range of snake-like objects. Most wild-reared monkeys showed considerable fear of the real, toy, and model snakes, whereas most lab-reared monkeys showed only very mild responses. Fear was indexed by unwillingness to approach food on the far side of the snake and by behavioral disturbance. Experiment 2 examined the effectiveness of seven flooding sessions in reducing snake fear in 8 wild-reared rhesus monkeys. Mean latency to reach for food, trials to criterion (four consecutive short latency responses), and total exposure time to criterion declined significantly across flooding sessions. Behavioral disturbance declined within sessions but not across sessions. Results of a final behavioral test revealed that substantial long-lasting changes had occurred in only 3 of the 8 monkeys. The results are discussed in the context of dissociation between different indices of fear.  相似文献   

2.
15 low birth weight and 15 normal birth weight pigtailed monkey infants were administered an adaptation of a standardized test of visual recognition memory, originally developed for human infants. Animals were given a series of problems in which 2 identical black-and-white patterns were presented for a familiarization period. The previously exposed pattern was then paired with a novel one, and looking time to each pattern was recorded. The normal birth weight animals directed a significant amount of their visual attention to the novel stimuli, thus demonstrating recognition abilities. As a group, the performance of the low birth weight infants remained at chance. These findings have important implications for an animal model to examine factors contributing to poor cognitive outcome in low birth weight human infants.  相似文献   

3.
Separate groups of pigeons were trained to perform symbolic delayed matching to sample with auditory and visual sample stimuli. For animals in the auditory group, ambient tones that varied in frequency served as sample stimuli; for animals in the visual group, ambient red and green lights served as sample stimuli. In both cases, the sample stimuli were mapped onto the yellow and blue comparison stimuli presented on left and right pecking keys. In Experiments 1 and 2, it was found that visual and auditory delayed matching were affected in the same ways by several temporal variables: delay, length of exposure to the sample stimulus, and intertrial interval. In Experiments 3, 4A, and 4B, a houselight presented during the delay interval strongly interfered with retention in both visual and auditory groups, but white noise presented during the delay had little effect in either group. These results seem to be more in line with a prospective memory model, in which visual and auditory sample stimuli are coded into the same instructional memories, than with a model based on concepts of retrospective memory and modality specificity.  相似文献   

4.
Delayed matching-to-sample was used to study the effects of sample presentation time and spaced repetition upon delayed matching accuracy in one stumptail monkey and three squirrel monkeys. It was found in Experiment 1 that presenting the sample stimulus for 0.5 sec led to lower matching accuracy than was the case with longer presentation times of 2.5, 5.0, and 10.0 sec. Experiments 2 and 3 investigated the effects of temporally spacing the presentations of the sample stimulus. It was found that spaced repetition led to a deterioration of performance relative to massed repetition. These results are similar to the findings of experiments with pigeons and are contradictory to several previous experiments with monkeys or apes which found no effect of presentation time and a facilitative effect of spaced repetition. It is suggested that the use of monkeys inexperienced in short sample duration matching and tested in operant chambers using a limited set of noncomplex stimuli may be responsible for the discrepancies between these results and those of other experiments with primates.  相似文献   

5.
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   

6.
In Experiment 1, short-term memory for lists of visual stimuli was studied in four squirrel monkeys (Saimiri sciureus). A delayed-matching procedure was used in which a subject was presented with lists containing one, three, or six stimulus patterns, and memory for serial positions was probed by requiring the subject to choose between a list item and a nonlist item. The rate of item presentation was varied, as was the delay between the final item on a list and the retention test. In Experiment 2, the same procedures were used to compare recognition memory in four monkeys and four humans. Although differences in the levels and shapes of the serial-position curves appeared between species, both monkeys and humans showed primacy and recency effects. The presentation time of stimuli had a negligible effect on performance in both monkeys and humans, whereas delay significantly affected human retention but not monkey retention.  相似文献   

7.
8.
Short-term memory for order information in pigeons was explored by using a delayed matching-to-successive-samples task (DMTSS). Experiment 1 indicated that pigeons can accurately report the order of two successively presented samples. Experiments 2, 3 and 4 specifically addressed the representation of order information in short-term memory. Experiment 2 showed that when the duration of the first sample (S1) was very long, or when the duration of the second sample (S2) was very short, order errors increased relative to baseline (S1 and S2 of equal duration), suggesting that memory strength plays an important role in the discrimination of order. The possibility that strength information is necessary for accurate DMTSS performance was tested in Experiments 3 and 4. Pigeons continued to match accurately when memory strength and order were uncorrelated.  相似文献   

9.
10.
This study determined the degree to which the phonological and executive components of memory reflect language-specific capacities in Spanish and English vocabulary. We tested whether the memory processes in a sample of English language learners found in Grade 1 also emerged in Grade 2. For the total sample (N = 90), Grade 1 English STM measures shared a common construct with Spanish STM, whereas Grade 2 STM measures were language dependent. In contrast, WM measures were language independent across grades 1 and 2. When vocabulary subgroups were analyzed, a subgroup × type of memory task emerged. The results showed that performance on Spanish and English STM tasks were a function of high and low Spanish and English vocabulary knowledge, whereas WM was not. The relationship between language-specific processes in memory was discussed.  相似文献   

11.
The retention performance following partial training (15 trials) of a brightness-discrimination avoidance task has been shown to fluctuate over time, with a drop in performance 1 h after training (Kamin effect), a long-term spontaneous improvement (LTSI) after 3 days, and long-term spontaneous forgetting after 21 days. The purpose of this paper was to determine if these time-dependent modulations of retention performance reflect time-dependent modifications in the organization of the attributes that constitute the memory trace. We studied the relative effectiveness of several pretest cuings on retention performance when they were delivered just before a retention test occurring 1 h, 3 days, or 21 days following initial training. Some cuing treatments were related to a particular training event (conditioned or unconditioned stimulus, experimental context). Compound cuings, composed of two or more training events, were also studied to test a possible additive effect between retrieval cues. To demonstrate time-dependent modifications in the memory trace, a differential effectiveness over time was expected for at least some retrieval cues. The results show that cuing may compensate for performance deficits (1 h or 21 days), but does not further enhance performance when spontaneously improved (3 days). No detectable additive effects of retrieval cues were obtained. However, these results provide information that suggests a time-dependent effectiveness for some cuing treatments. In the last experiment, we investigated this possibility by studying the effects of each of these treatments when delivered after either a 1-h or a 21-day retention interval. The results confirm a time-dependent decrease in effectiveness of a pretest exposure to the CS and an increase in effectiveness over time of a pretest exposure to the experimental context or to a well-ordered sequence of events. Such differential retrievability of a partially learned episode according to both the nature of the cues and the length of the retention interval suggests a time-dependent reorganization of memory attributes.  相似文献   

12.
The monkey’s capacity to extract tonal pattern from a sequence of tones was assessed in four subjects that had the benefit of substantial past experience in discriminating, matching, and remembering acoustic stimuli. In Experiment 1, the monkeys failed to transfer their well-established matching behavior to the matching of two structured sequences of tones that differed primarily in tonal pattern, indicating that for them tonal pattern was not a salient feature of the acoustic stimuli. Experiment 2 was an attempt to encourage tonal pattern perception by employing, within a discrimination paradigm, very simple tonal patterns and multiple exemplars of the positive and negative patterns; the transfer design, borrowed from Hulse and Cynx (1985), was a powerful one for revealing tonal pattern perception. Verifying earlier results from our laboratory, there was little in the monkeys’ transfer performance to indicate that they had extracted tonal pattern from the acoustic stimuli. Major discriminative control seemed to be vested in the first tone of each exemplar. This apparent cognitive limitation may be rather general among animals, perhaps reflecting an intimate connection between the capacity for tonal pattern perception and that for acoustically based language.  相似文献   

13.
In making comparative judgments about pairs of stimuli that are linearly ordered, human subjects usually respond faster the greater the separation between-the-items of a test pair—the symbolic distance effect. A similar result has been obtained for associatively related items, such as the alphabet. We report evidence for a distance effect in monkeys tested with pairs of items drawn from a five-item series with which they had considerable previous experience-in a serial learning setting. This finding provides independent evidence that in learning a serial list of items, monkeys acquire knowledge about the ordinal positions of the items. Analysis of the positive results obtained in Experiment 2 and of the failure to find a distance effect in Experiment 1 suggested that in learning a serial list, monkeys construct both an associative chain representation of the series and a spatial representation, with the latter supplying the spatial markers that convey positional information. This dual coding of sequential events, which may be rather general among mammals, probably supports a variety of cognitive competencies.  相似文献   

14.
Monkeys and rats were trained on an operant discrimination employing structured auditory stimuli (tunes). The rats acquired the tune discrimination very rapidly and considerably faster than the monkeys. Both species generalized the discrimination across intensity and octave transformations. Discriminative performance remained at a high level when only the first halves of the tunes were presented, but substantially less generalization occurred to the second halves. Rats trained with tones (broken or steady) required three to four times more training to reach criterion than did the rats trained with tunes. The potential of structured auditory stimuli for investigations of information-processing mechanisms in animals is pointed out.  相似文献   

15.
Two squirrel monkeys searched for a reward buried in 1 of 144 holes that formed a 12×12 grid (48×50 cm). An array of vertical, colored landmarks was placed on the grid, and their locations on the grid were changed from trial to trial. During training trials, the mealworm reward was placed either in the center of a square array of landmarks (Experiments 1 and 3) or midway between two landmarks (Experiment 2). On nonrewarded test trials, the monkeys searched among landmarks placed in the same arrays as those used in training and among landmarks placed in an expanded array (Experiments 1 and 2) or in an array intermediate between the two arrays used in training (Experiment 3). Distributions of searches on test trials indicated that the monkeys searched mostly within the configuration of the landmarks but that they had not coded the location of the reward as being either in the middle of the landmarks or at a fixed distance and direction from an individual landmark.  相似文献   

16.
17.
We trained two budgerigars (Melopsittacus undulatus) with operant techniques in a delayed matching-to-sample task using pairs of acoustic stimuli. These stimuli included simple pure tones, complex, species-specific vocalizations, and tone-vocalization combinations. The birds were then tested with different retention intervals. The budgerigars’ short-term memory was similar for complex, species-specific vocalizations and for simple pure tones. By contrast, they showed significantly better short-term memory when tested with two sounds drawn from different acoustic categories.  相似文献   

18.
D’Amato  M. R.  Salmon  David P.  Loukas  Eric  Tomie  Art 《Learning & behavior》1986,14(4):365-373
Learning & Behavior - As a test of differential processing of identity and conditional relations, subjects were first highly trained on 0-sec delay identity matching (IM) and conditional...  相似文献   

19.
The degree to which rats and monkeys base their discriminations of complex auditory stimuli (“tunes”) on frequency contours rather than on local features was investigated. In Experiment 1, groups of rats and monkeys trained with tunes as S+ and S? acquired a simple operant discrimination no faster than groups that received the same notes of each tune but in a new random order on each trial; neither did the groups differ on two transfer tests devised to detect learning of frequency contour in the tune-trained animals. Acquisition in the tune-trained and random-notes groups seemed to be based on the overall frequency difference between S+ and S?, which was about 1.5 octaves. In Experiment 2, S+ and S? were similar to each other with regard to overall frequency and individual notes, the most salient differentiating characteristic of the tunes being their tonal pattern. The tune-trained groups were clearly superior to the random-notes animals in acquisition, and an initial transfer test suggested that the former might have learned the discrimination on the basis of frequency contour. However, the detailed transfer tests of Experiment 3 strongly suggested that the tune-trained rats and monkeys based their discriminations primarily on local cues rather than on frequency contour. Based on the results of Experiment 4, the data of an earlier study that suggested frequency contour learning in monkeys and rats were reinterpreted in terms of control by local cues.  相似文献   

20.
A theoretical scheme was suggested which distinguished between absolute and relative class concepts and differentiated class from relational concepts. Four monkeys were trained to respond differentially to green and nongreen objects (absolute class) and four responded differentially to odd and nonodd objects (relative class). All monkeys met stringent criteria of performance on their respective tasks, the green-nongreen group in a median of 600 trials and the odd-nonodd group in a median of 1,600 trials (p = .014). Possible explanations for the performance differences and some implications of the theory for comparative, nonhuman conceptual research were discussed.  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