共查询到20条相似文献，搜索用时 31 毫秒
1.
Pigeons and adult humans searched for a 2-cm2 unmarked goal in digitized images of an outdoor scene presented on a touch-screen monitor. In Experiment 1, the scene contained three landmarks near the goal and a visually rich background. Six training images presented the scene from different viewing directions and distances. Subsequent unreinforced tests in which landmark or background cues were removed or shifted revealed that pigeons’ search was controlled by both proximal landmarks and background cues, whereas humans relied only on the proximal landmarks. Pigeons’ search accuracy dropped substantially when they were presented with novel views of the same scene, whereas humans showed perfect transfer to novel views. In Experiment 2, pigeons with previous outdoor experience and humans were trained with 28 views of an outdoor scene. Both pigeons and humans transferred well to novel views of the scene. This positive transfer suggests that, under some conditions, pigeons, like humans, may encode the three-dimensional spatial information in images of a scene. 相似文献
2.
In Experiment 1, it was shown that generalization testing following successive discrimination training between two closely spaced wavelengths results in a sharp gradient with a peak of responding shifted from S+ so as to be further removed from S?. Testing after a 24-h delay resulted in a flatter gradient with greater peak (and area) shift. A 5-min pretest exposure to S+, reinforced or unreinforced, or to S? (unreinforced) reinstated immediate test performance; free reinforcement with no discriminative stimulus present had no such effect. Experiment 2 replicated the flattening of generalization gradients and enhanced peak shift in delayed testing. Free feeding in a pretest treatment with a distinctive food uniquely associated with the wavelength discrimination problem failed to reinstate immediate test performance. Experiment 3 tested the hypothesis that free feeding failed as a reactivation treatment because it did not engender keypecking. Subjects were trained to peck a vertical line stimulus before being given wavelength discrimination training. Again, the enhanced peak shift and greater flattening with delayed wavelength generalization testing was found. A pretest exposure to the vertical line stimulus elicited pecking but had no effect on subsequent wavelength generalization. Thus, only a reactivation treatment that included one of the discrimination training stimuli was effective in producing delayed test performance comparable to that obtained in an immediate test. 相似文献
3.
Emily W. Bushnell Beryl E. McKenzie Deborah A. Lawrence Sheryl Connell 《Child development》1995,66(4):937-958
The ability of 1-year-old infants to remember the location of a nonvisible target was investigated in 3 experiments. Infants searched for a toy hidden in one of many possible locations within a circular bounded space. The presence, number, and spatial arrangement of local cues or "landmarks" within this space were varied. The results of Experiment 1 showed that search performance was highly successful when a landmark was coincident with the location of the toy ("direct"), but less successful when a landmark was adjacent to the target location ("indirect"). The results of Experiment 2 suggested that search with an indirect landmark may be more fragile than search with no landmarks at all. In Experiments 3a and 3b, 2 different configurations of indirect landmarks were employed; search performance was equally poor with both of these and was inferior to search with no landmarks. It is concluded that infants of this age are able to associate a nonvisible target with a direct landmark and are able to code the distance and direction of a target with respect to themselves or with respect to the larger framework. However, there was no evidence that they can code the distance and direction of a target relative to another object. The difficulty of coding with indirect landmarks is interpreted in terms of cognitive complexity and conflict between spatial strategies. 相似文献
4.
Pigeons trained monocularly and tested with the trained eye along the angularity dimension were found to show enhanced area shifts when compared to pigeons trained and tested binocularly. Pigeons trained monocularly and tested with the untrained eye showed reversed peak shifts in the direction of S?. These findings are consistent with the hypothesis that the mirror image of S? in angularity gradients functions to reduce the likelihood of the peak shift and area shift along the angularity dimension in pigeons, and question the use of the angularity dimension for intradimensional discrimination training and generalization testing. 相似文献
5.
Five experiments examined 79 newborns’ ability to discriminate and categorize a spatial relation, defined by the left–right spatial position of a blinking object‐target with respect to a vertical landmark‐bar. Three‐day‐old infants discriminated the up versus low position of an object located on the same side of the landmark‐bar (Experiment 1) and recognized a basic left–right spatial invariance of the object‐target and the landmark‐bar in conditions of low (Experiment 2) and high (Experiment 3) perceptual variability of the object’s positions. Additional evidence ruled out the possibility that newborns were unable to discriminate the within‐category left–right spatial positions of the object‐target (Experiment 4) or made a categorical distinction based on spatial distance rather than on categorical spatial relations of left of and right of (Experiment 5). 相似文献
6.
Two experiments tested blocking in landmark-based search in honeybees. Honeybees in the experimental group were trained in Phase 1 with a single landmark in a constant spatial relation to the target (sugar water). In the compound training second phase, the landmark used in Phase 1 (blocking landmark) and a new landmark (blocked landmark) were presented at constant spatial relations to the target. The blocking and blocked landmarks differed from each other in color and position, and the blocking landmark retained the same spatial relationship to the target as in Phase 1. In Experiment 1, the control group experienced only Phase 2 training with two landmarks. In Experiment 2, the control group was trained with a different landmark in a different position in Phase 1. Blocking was found in both cases. 相似文献
7.
Chad M. Ruprecht Joshua E. Wolf Nina I. Quintana Kenneth J. Leising 《Learning & behavior》2014,42(3):215-230
During feature-positive operant discriminations, a conditional cue, X, signals whether responses made during a second stimulus, A, are reinforced. Few studies have examined how landmarks, which can be trained to control the spatial distribution of responses during search tasks, might operate under conditional control. We trained college students to search for a target hidden on a computer monitor. Participants learned that responses to a hidden target location signaled by a landmark (e.g., A) would be reinforced only if the landmark was preceded by a colored background display (e.g., X). In Experiment 1, participants received feature-positive training (+←YB/ XA→+/A?/B?) with the hidden target to the right of A and to left of B. Responding during nonreinforced transfer test trials (XB?/YA?) indicated conditional control by the colored background, and spatial accuracy indicated a greater weighting of spatial information provided by the landmark than by the conditional cue. In Experiments 2a and 2b, the location of the target relative to landmark A was conditional on the colored background (+←YA/ XA→+/ ZB→+/ +←C /A?/B?). At test, conditional control and a greater weighting for the landmark’s spatial information were again found, but we also report evidence for spatial interference by the conditional stimulus. Overall, we found that hierarchical accounts best explain the observed differences in response magnitude, whereas spatial accuracy was best explained via spatial learning models that emphasize the reliability, stability, and proximity of landmarks to a target. 相似文献
8.
Ken Cheng 《Learning & behavior》1998,26(4):455-468
Honeybees were trained with two landmarks at some angle (e.g., 120°) apart from the target. On crucial unrewarded tests, only a single landmark was present. If distances and directions to landmarks are computed separately (independent averaging), the search distance to the landmark should equal the landmark-target distance found in training. If entire vectors are averaged, the search distance should be much shorter. Three experiments with short target-landmark distances showed results in between the predictions of the two hypotheses. A fourth experiment used longer target-landmark distances and isolated double peaks on single-landmark tests: one predicted by the independent averaging hypothesis, and one very close to the landmark. The near peak is interpreted as arising from approach and exploration of a landmark in a new location, and not from searching. 相似文献
9.
Learning to discriminate stimuli can alter how one distinguishes related stimuli. For instance, training an individual to
differentiate between two stimuli along a single dimension can alter how that individual generalizes learned responses. In
this study, we examined the persistence of shifts in generalization gradients after training with sounds. University students
were trained to differentiate two sounds that varied along a complex acoustic dimension. The students were subsequently tested
on their ability to recognize a sound that they had experienced during training when it was presented among several novel
sounds varying along this same dimension. Peak shift was observed in Experiment 1, in which generalization tests immediately
followed training, and in Experiment 2, in which the tests were delayed by 24 h. These findings further support the universality
of generalization processes across species, modalities, and levels of stimulus complexity. They also raise new questions about
the mechanisms underlying learning-related shifts in generalization gradients. The sound stimuli from this study are available
as .wav files from http://lb.psychonomic-journals.org/content/supplemental. 相似文献
10.
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
11.
Pigeons responded in a two-component peak procedure in which the components differed in terms of reinforcement magnitude (Experiment 1), immediacy (Experiment 2), or probability (Experiment 3). The prediction of behavioral momentum theory that responding in the relatively richer component should be more resistant to change was tested by (1) presenting response-independent food in the intervals between components according to a variable-time (VT) schedule, (2) prefeeding, and (3) extinction. In all the experiments, peak location in baseline occurred earlier, relative to the schedule value in the richer component. Peak response rate was more resistant to change in the richer component during the VT and prefeeding tests, and change in peak rate was more sensitive to differential reinforcement than change in overall response rate. Changes in measures of performance on peak trials during the disruptor tests were partially consistent with predictions of the behavioral theory of timing. The results suggest that peak response rate provides a more sensitive index of resistance to change for fixed-interval schedules than does overall response rate and that reinforcement strengthens both peak responding and temporal control. 相似文献
12.
T. Gary Waller 《Learning & behavior》1974,2(4):298-304
Experiment I compared constant (CI), variable-between (VBI), and variable-within (WVI) irrelevant cues during an extradimensional (ED) shift discrimination. Performance was better for CI than for VBI and better for VBI than for VWI. Experiment II combined CI, VBI, and VWI cues with ED or intradimensional (ID) shifts. Irrelevant-cue conditions did not affect ID performance but did affect ED performance. The typical superiority of ID, as compared to ED, shifts was observed in the VWI condition but not in the CI condition. Implications for mediating-response (i.e., attention or observing-response) theories were indicated. 相似文献
13.
The goal of the present study was to examine the mechanisms underlying a strategy that we developed to make instructional explanations effective. In two experiments participants learned about plate tectonics from a multimedia material, including adjunct explanations that revised common misunderstandings. These explanations were either marked (including a device that pointed out the misunderstanding that the explanation was intended to revise) or unmarked. In both experiments participants receiving marked revising explanations outperformed those receiving unmarked ones in retention and transfer. In Experiment 1, think-aloud protocols revealed that marked revising explanations enabled learners to detect and repair flaws in their understanding more frequently than unmarked explanations. In Experiment 2, time recordings revealed that participants in the marked condition spent more time processing the revising explanations. Overall, the results mean that the revising instructional explanations that point out learners' misunderstandings promote a revision-oriented processing, in which learners monitor and revise their own understanding. 相似文献
14.
Contrast in consummatory behavior was investigated following repeated shifts from 32% to 4% sucrose. In Experiment 1, contrast in licking and in open-field measures of activity occurred following the second and third downshifts. In Experiments 2a and 2b, equivalent contrast effects occurred following the first and second downshifts in sucrose. In Experiment 3, negative contrast remained unabated following nine downshifts in animals shifted between 32% and 4% sucrose on alternate days. Similar results were found for five downshifts in animals shifted every 2 days. In both of these latter conditions, positive contrast occurred over the first few shifts and was then lost as the 32% control group reached asymptote. These data show that repeated negative contrast effects in consummatory behavior are robust and enduring and occur under several different sets of experimental parameters. The results are discussed in terms of reinforcement level and emotional interpretations of contrast effects, and the possibility was suggested that the causal mechanism of contrast changes with repeated shifts. 相似文献
15.
Two-year-olds' (N = 153) knowledge of solidity was tested in four search tasks adapted from infant looking-time experiments. In Experiment 1, 2-year-olds failed to search in the correct location for a falling ball after a hidden shelf that blocked its trajectory had been inserted in the apparatus. Experiment 2 extended this finding by showing that 2-year-olds failed to take into account the effects of either removing or inserting a shelf in their search for a toy dropped behind a screen. Experiment 3 examined sensitivity to the constraint provided by a solid barrier on horizontal motion. In all three experiments, 2-year-old children searched initially at the location where they saw the object during familiarization. Experiment 4, using multiple test trials but no familiarization to a pretest location, also showed that 2-year-olds failed to take the presence or absence of a barrier into account when planning where to search for a toy they had seen dropped behind a screen. In all of these studies, 2-year-olds showed no evidence of representing solidity and support constraints on the trajectories of falling objects. Experiments 1 and 3 also included 2 1/2-year-olds (N = 31), who succeeded on these search tasks. The implications of the poor performance of 2-year-olds, in the face of success by very young infants on looking-time measures of sensitivity to similar constraints on object motion, are discussed. 相似文献
16.
Rats were trained in a triangular-shaped pool to find a hidden platform that maintained a constant relationship with two sources
of information, an individual landmark and one part of the pool with a distinctive shape. In Experiment 1, shape learning overshadowed landmark learning but landmark learning did not overshadow shape learning in males, while landmark
learning overshadowed shape learning but shape learning did not overshadow landmark learning in females. In Experiment 2,
rats were pretrained either with the single landmark relevant or with the shape relevant, in the absence of the alternative
cue. Final test trials, without the platform, revealed reciprocal blocking only in females; in males, shape learning blocked
landmark learning, but not viceversa (Experiment 2a). In Experiment 2b, male rats received a longer pretraining with the single landmark relevant, and now landmark learning blocked shape learning.
The results thus confirm the claim that males and females partially use different types of spatial information when solving
spatial tasks. These results also agree with the suggestion that shape learning interacts with landmark learning in much the
same way as does learning about any pair of stimuli in a Pavlovian conditioning experiment. 相似文献
17.
Perceptron models have been used extensively to model perceptual learning and the effects of discrimination training on generalization, as well as to explore natural classification mechanisms. Here, we assess the ability of existing models to account for the time course of generalization shifts that occur when individuals learn to distinguish sounds. A set of simulations demonstrates that commonly used single-layer and multilayer perceptron networks do not predict transitory shifts in generalization over the course of training but that such dynamics can be accounted for when the output functions of these networks are modified to mimic the properties of cortical tuning curves. The simulations further suggest that prudent selection of stimuli and training criteria can allow for more precise predictions of learning-related shifts in generalization gradients in behavioral experiments. In particular, the simulations predict that individuals will show maximal peak shift after different numbers of trials, that easier contrasts will lead to slower development of shifted peaks, and that whether generalization shifts persist or dissipate will depend on which stimulus dimensions individuals use to distinguish stimuli and how those dimensions are neurally encoded. 相似文献
18.
Three experiments investigated temporal generalization in humans. In Experiment 1, a peak shift effect was produced when participants
were given intradimensional discrimination training. In Experiment 2, after training with a standard S1 and generalization
testing with an asymmetrical series of durations, generalization gradients moved toward the prevailing adaptation level. In
Experiment 3, generalization gradients showed a central tendency shift and moved away from the S1 and toward the mean of the
test series (of 11 stimulus durations) after participants received training with S1 and S2 durations that in one condition
were the 2nd and 4th and in another condition were the 4th and 2nd stimuli in the series, respectively. The results were inconsistent
with an absolute account of peak shift but were consistent with an adaptation level account of peak shift. 相似文献
19.
姚宇新 《辽宁科技学院学报》2005,7(1):19-21
利用分形和分维数的基本概念,推导出粉碎最终产品的分维数.利用能耗与粉碎最终产品颗粒表面积相关的观点,推导出单位体积粉碎能耗的分维数.利用分形的自相似性,推导出能耗的无标度域与粉碎粒度分布指数的相关性. 相似文献
20.
V. D. Chamizo Clara A. Rodríguez Irene Torres Marta N. Torres N. J. Mackintosh 《Learning & behavior》2014,42(4):348-356
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