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1.
The performances of adult and aged macaque monkeys were compared on several tasks requiring acquisition and retention of concurrent object discriminations. Cross-sectional and longitudinal comparisons between 11-year-old and over-20-year-old animals were conducted on the acquisition of several 16-problem concurrent tasks, and after 2 weeks, retention by the different age groups was also evaluated. Although the retention tests indicated no age-related impairment, acquisition tests showed that aged animals made reliably more errors-to-criterion than did adult animals. The relative contributions of intersession and intrasession improvement and preference phenomena were considered and contrasted to some previously reported age-specific outcomes. Although the present results affirmed the contention that old animals were selectively impaired on intersession task requirements, some earlier interpretations of preference effects were questioned. Old animals did not show a potentiation of specific object preferences; rather, they tended to be nonsystematic in maintaining their selection of initially preferred objects. Concurrent discrimination was indicated to be a behavioral measure that is, under appropriate circumstances, selectively sensitive to aging and may offer an appropriate comparative model of information-processing characteristics.  相似文献   

2.
Eight rhesus monkeys were trained on a counterbalanced series of concurrent, two-choice, discrimination tasks that provided different numbers of correct or incorrect objects as lists of discriminanda. Small, large, or infinite lengths of correct or incorrect object lists were combined in different tasks, and acquisition performances were compared. When tasks had an infinite number of objects in their correct list and a small number (4) in their incorrect list, acquisition entailed significantly less error than was seen when a small number of correct objects was paired with an infinite incorrect list. This pattern of outcomes seemed attributable to novelty preference. However, comparison of error distributions from tasks with infinite. list lengths to distributions from analogous tasks with fixed list lengths provided some basis for interpreting the way monkeys integrated information that emerged from the temporally discriminative properties of the tasks. One prospective concern was whether or not these performances represented behaviors like those seen in human cognitive discriminations of frequency of occurrence.  相似文献   

3.
Pigeons were trained on two visual discrimination tasks. One task was discrimination between real objects and their photographs. Training stimuli consisted of real food (grains), photographs of food, and nonedible junk objects and their photographs. The other task was discrimination between food and nonfood using the same stimuli as those in the first task. The pigeons learned either task and showed generalization of these classifications to novel stimuli. These results suggest that pigeons can either discriminate or integrate real stimuli and their photographs. Bilateral ectostriatal lesions caused deficits in food versus nonfood discrimination, but not in object versus picture discrimination. This dissociation suggests different brain mechanisms between the two visual discriminations using the same stimuli.  相似文献   

4.
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   

5.
Delayed simple discriminations are typically retained more accurately over longer delays by pigeons than are delayed conditional discriminations (e.g., Honig & Wasserman, 1981). In two experiments, we investigated the extent to which trial outcomes contribute to this difference by comparing performances when all trials ended with food reinforcement versus when only half of the trials did. Experiment 1 showed that when food was presented on all trials, contingent upon either pecking or not pecking the test stimulus, levels of retention and rates of forgetting were comparable for these two tasks. By contrast, Experiment 2 showed better retention of delayed simple than delayed conditional discriminations when half of the trials ended with food and the other half in extinction. Furthermore, delayed simple discriminations were retained more accurately with food versus no-food outcomes than with food at the end of every trial, whereas the reverse was true for delayed conditional discriminations. These findings indicate that retention differences between these tasks are another instance of the differential outcomes effect.  相似文献   

6.
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   

7.
8.
2 studies investigate whether 18-month-old children spontaneously sort objects into basic-level categories, and how this ability is related to naming. In Study 1, 18-month-old children were given spontaneous sorting tasks, involving both identical objects and objects with basic-level intracategory variation. Children were scored as having passed the tasks if they produced "exhaustive grouping," that is, physically grouped all the objects of one kind into one location and the objects of the other kind into a different location. The children also received means-ends and object-permanence tasks. Children's parents received a checklist of early names. Children who produced exhaustive grouping used significantly more names than those who did not, in both identical and basic-level cases. There was no such relation between object-permanence and naming or between means-ends performance and naming. In Study 2, children received arrays of the same objects, with either identical objects or objects with basic-level variation in each group. No significant differences were found between the identical and basic-level tasks. However, as in the previous task, performance on both types of categorization was related to naming. Children who produced exhaustive grouping were reported to produce more names than those who did not. There appears to be a close relation between object categorization and naming in young children. The theoretical implications of this empirical association are discussed.  相似文献   

9.
Rhesus monkeys were trained to press panels to escape or avoid shock. Escape and avoidance training were combined factorially with feature-positive (FP) and feature-negative (FN) discriminations. In the FP situation, S+ trials were characterized by one red and two green panel displays and S? consisted of an all green panel array. In the FN arrangement, S+ and S? arrays were reversed. When compared properly, FP discriminations were learned more readily than FN discriminations in both escape and avoidance training conditions. Positive tracking was associated with FP discriminations, and feature avoidance characterized the FN tasks. These data suggest that in primates, feature responses (i.e., tracking behaviors) are more a function of the operant contingency than of the Pavlovian correlation.  相似文献   

10.
Both empirical and anecdotal evidence supports the idea that choice is preferred by humans. Previous research has demonstrated that this preference extends to nonhuman animals, but it remains largely unknown whether animals will actively seek out or prefer opportunities to choose. Here we explored the issue of whether capuchin and rhesus monkeys choose to choose. We used a modified version of the SELECT task—a computer program in which monkeys can choose the order of completion of various psychomotor and cognitive tasks. In the present experiments, each trial began with a choice between two icons, one of which allowed the monkey to select the order of task completion, and the other of which led to the assignment of a task order by the computer. In either case, subjects still had to complete the same number of tasks and the same number of task trials. The tasks were relatively easy, and the monkeys responded correctly on most trials. Thus, global reinforcement rates were approximately equated across conditions. The only difference was whether the monkey chose the task order or it was assigned, thus isolating the act of choosing. Given sufficient experience with the task icons, all monkeys showed a significant preference for choice when the alternative was a randomly assigned order of tasks. To a lesser extent, some of the monkeys maintained a preference for choice over a preferred, but computer-assigned, task order that was yoked to their own previous choice selection. The results indicated that monkeys prefer to choose when all other aspects of the task are equated.  相似文献   

11.
The majority of children and adults with reading disabilities exhibit pronounced difficulties on naming-speed measures such as tests of rapid automatized naming (RAN). RAN tasks require speeded naming of serially presented stimuli and share key characteristics with reading, but different versions of the RAN task vary in their sensitivity: The RAN letters task successfully predicts reading ability, whereas the RAN objects task does not reliably predict reading after kindergarten. In this study we used functional magnetic resonance imaging to evaluate the neural substrates that may underlie performance on these tasks. In two scans during the same test session, adult, average readers covertly rapidly named objects or letters or passively viewed a fixation matrix of plus signs. For both rapid naming tasks compared with fixation, activation was found in neural areas associated with eye movement control and attention as well as in a network of structures previously implicated in reading tasks. This reading network included inferior frontal cortex, temporo-parietal areas, and the ventral visual stream. Whereas the inferior frontal areas of the network were similarly activated for both letters and objects, activation in the posterior areas varied by task. The letters task caused greater activation in the angular gyrus, superior parietal lobule, and medial extrastriate areas, whereas object naming only preferentially activated an area of the fusiform gyrus. These results confirm that RAN tasks recruit a network of neural structures also involved in more complex reading tasks and suggest that the RAN letters task specifically pinpoints key components of this network.  相似文献   

12.
This study investigates the usability of print and online video instructions for computer tasks. Usability tests, comprehension tests, and questionnaires were collected from participants, and 4 areas of usability were analyzed: effectiveness, retention, satisfaction, and preference. Findings show marginal differences between the 2 mediums, except in terms of user satisfaction and instruction length. This research helps technical communicators better understand the affordances, or potentials and limitations, of print and video instructions.  相似文献   

13.
In temporal discriminations tasks, more than one stimulus may function as a time marker. We studied two of them in a matching-to-sample task, the sample keylight and the houselight that signaled the intertrial interval (ITI). One group of pigeons learned a symmetrical matching-to-sample task with two samples (2 s or 18 s of a center keylight) and two comparisons (red and green side keys), whereas another group of pigeons learned an asymmetrical matching-to-sample task with three samples (2 s, 6 s, and 18 s) and two comparisons (red and green). In the asymmetrical task, 6-s and 18-s samples shared the same comparison. In a subsequent retention test, both groups showed a preference for the comparison associated with the longer samples, a result consistent with the hypothesis that pigeons based their choices on the duration elapsed since the offset of the houselight (i.e., sample duration + retention interval). Results from two no-sample tests further corroborated the importance of the ITI illumination as a time marker: When the ITI was illuminated, the proportion of choices correlated positively with the retention interval; when the ITI was darkened, choices fell to random levels. However, the absolute value of choice proportions suggested that the sample stimulus was also a time marker. How multiple stimuli acquire control over behavior and how they combine remains to be worked out.  相似文献   

14.
Two rhesus monkeys were tested in 6- and 10-item list memory tasks for performance changes as a function of the exposure duration of the list stimuli and the interstimulus interval (ISI) between successive list stimuli. Accuracy increased with longer item exposure duration and tended to decrease with longer ISI duration. Humans, by contrast, typically show increases in accuracy with ISI, a result taken as evidence of rehearsal. The decrease in accuracy for monkeys suggests that they were not using rehearsal processes in these list memory experiments. Further tests in which choice accuracy with predictable ISIs was compared with choice accuracy with unpredictable ISIs also yielded no evidence of rehearsal by the monkeys. This apparent absence of rehearsal mechanisms in monkeys, in situations also shown to support human rehearsal, is discussed as a potential difference in the visual working memory processes of the two species.  相似文献   

15.
Only a limited number of species have been found capable of generalized matching-to-sample (MTS) after exposure to relatively few training exemplars. We trained a juvenile, experimentally naive California sea lion (Zalophus californianus) in MTS, using a pair of three-dimensional objects as samples. Successful matching to a criterion of 90% correct or better over 2 successive sessions was attained in 12 sessions (269 trials and 70 errors). Two subsequent “partial” transfer tests, in which each of the two training objects was paired with a novel test object, and four additional transfer tests, all with novel objects, were presented following training. An 80% performance criterion over 2 successive sessions was reached, or closely approximated, in from 2 to 4 transfer sessions for all transfer tests; errors to criterion tended to be reduced across the successive novel transfer tests and were as few as five during the final two tests; and performance on the first 48 trials of the last two novel transfers was not significantly different from a near-ceiling level baseline performance measure. Neophobic responses of the sea lion to new objects precluded an unbiased evaluation of immediate (Trial 1) transfer. The sea lion’s short-term memory for sample objects was also measured. Matching performance was maintained at a level of 78% correct responses or better for delays through to 45 sec after removal of the sample object. At a 58-sec delay, the longest tested, performance declined to 69% correct responses. These retention levels are only somewhat below levels reported for dolphins and nonhuman primates tested on visual delayed MTS, but they are above levels typically reported for pigeon subjects.  相似文献   

16.
2 studies investigated young children's understanding that as the retention interval increases, so do the chances that one will forget. In Study 1 (24 3-year-olds and 24 4-year-olds), 4-year-olds but not 3-year-olds understood that of 2 characters who simultaneously saw an object, the character who waited longer before attempting to find it would not remember where it was. In study 2 (24 3-year-olds and 24 4-year-olds), 4-year-olds but not 3-year-olds understood that of 2 objects seen by a character, the object that was seen a "long long time ago" would be forgotten and the object seen "a little while ago" would be remembered. The findings are discussed in relation to research on young children's understanding of the acquisition, retention, and retrieval of knowledge over time.  相似文献   

17.
One captive adult chimpanzee and 3 adult American black bears were presented with a series of natural category discrimination tasks on a touch-screen computer. This is the first explicit comparison of bear and primate abilities using identical tasks, and the first test of a social concept in a carnivore. The discriminations involved a social relationship category (mother/offspring) and a nonsocial category involving food items. The social category discrimination could be made using knowledge of the overarching mother/offspring concept, whereas the nonsocial category discriminations could be made only by using perceptual rules, such as “choose images that show larger and smaller items of the same type.” The bears failed to show above-chance transfer on either the social or nonsocial discriminations, indicating that they did not use either the perceptual rule or knowledge of the overarching concept of mother/offspring to guide their choices in these tasks. However, at least 1 bear remembered previously reinforced stimuli when these stimuli were recombined, later. The chimpanzee showed transfer on a control task and did not consistently apply a perceptual rule to solve the nonsocial task, so it is possible that he eventually acquired the social concept. Further comparisons between species on identical tasks assessing social knowledge will help illuminate the selective pressures responsible for a range of social cognitive skills.  相似文献   

18.
In two experiments, participants acquired one of two target configural discriminations (a biconditional or negative patterning discrimination) in a predictive learning task. In Experiment 1, participants were pretrained with either a configural or an elemental discrimination; in Experiment 2, they were pretrained with a configural discrimination, an elemental discrimination, or a control discrimination that was not expected to bias them toward elemental or configural processing. In both experiments, acquisition of the target configural discriminations was faster after configural pretraining than after elemental pretraining. In addition, the negative patterning discrimination was acquired faster than the biconditional discrimination. Finally, the results of Experiment 2 were more consistent with the notion that elemental pretraining hindered acquisition of the target discriminations than with the notion that configural pretraining enhanced their acquisition. Implications of these findings are discussed.  相似文献   

19.
Cebus monkeys explored a small T-maze for 5 min, and their preference for the striped or black arm of the maze was assessed. On the next day, the experimental animals were placed into the nonpreferred arm for a 1-min period (exposure to the CS), removed from the T-maze for a 30-min delay interval, and then returned to the startbox of the maze, where they received a food reward (UCS). One control group (CS only) received the placement experience but was not rewarded after the 30-min period. A second control group (noncontingent UCS) received the reward in the startbox but not the placement experience. A second preference test showed that the experimental, but not the control, animals reversed their original preference, now showing a preference for the arm associated with reward. A retention test given 4 months after three such training-test trials revealed considerable retention of the preferences exhibited by the experimental and CS-only control subjects.  相似文献   

20.
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