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1.
Rats were trained to find the hidden platform in a Morris pool, whose location was defined by reference to a small number
of landmarks around the circumference of the pool. In each of three experiments, an experimental group was trained on alternate
trials with two different subsets of three of the available landmarks, with the two subsets sharing one landmark in common.
When tested with landmarks drawn from both of their training configurations, but without the landmark common to the two sets,
they had no difficulty in locating the platform. In Experiment 1, they performed at least as well as a group trained with
all the available landmarks present on every trial. In Experiment 2, they performed significantly better than a group trained
with two different subsets of landmarks that shared no one landmark in common. 相似文献
2.
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
3.
Kenneth J. Leising Jared Wong Chad M. Ruprecht Aaron P. Blaisdell 《Learning & behavior》2014,42(4):357-364
Many studies investigating cue competition have focused on the blocking effect. We investigated the blocking effect with pigeons using a landmark-based spatial search task in both a touchscreen preparation (Exp. 1a) and an automated remote environmental navigation apparatus (Exp. 1b). In Phase 1, two landmarks (LMs: A and Z) appeared on separate trials as colored circles among a row of eight (touchscreen) or six (ARENA) identical response units. Subjects were rewarded for pecking at a target response unit to the right of LM A and to the left of an extraneous LM, Z. During the blocking trials in Phase 2, LM X was presented in compound with a second LM (A) that had been previously trained. On control trials, LM Y was presented in compound with LM B and a target in the same manner as in the trials of AX, except that neither landmark had previously been trained with the target. All subjects were then tested with separate trials of A, X, B, and Y. Testing revealed poor spatial control by X relative to A and Y. We report the first evidence for a spatial-blocking effect in pigeons and additional support for associative effects (e.g., blocking) occurring under similar conditions (e.g., training sessions, spatial relationships, etc.) in 3-D and 2-D search tasks. 相似文献
4.
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
5.
In four trace-conditioning experiments with rats, the influence on the blocking of differences between the blocking cue-unconditioned
stimulus (US) and the blocked cue-US trace intervals was explored. Experiment 1 demonstrated blocking despite the blocked
cue’s having a shorter trace interval than the blocking cue in both elemental (Phase 1) and compound (Phase 2) training. In
Experiment 2, blocking was attenuated when the blocked cue had a longer trace interval than did the blocking cue in both elemental
and compound training. In Experiments 3 and 4, the trace intervals of the two cues during compound training were matched (i.e.,
unlike in Experiments 1 and 2, neither had temporal priority). Blocking was attenuated when the blocking cue trace interval
in the elemental phase was shorter (Experiment 3) or longer (Experiment 4) than the compound cue trace during compound training.
The findings indicate that subjects encode interstimulus intervals, and they further suggest that cue competition is greatest
when the competing cues have the same temporal information as the US. 相似文献
6.
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
7.
Foraging honeybees were trained in a concurrent blocking design with a compound stimulus (AX) reinforced and one of its components (A) either reinforced for a blocking group or nonreinforced for a control group. In Experiment 1, a compound of two colors was used; in Experiment 2, a compound of two odors was used; in Experiment 3, a color-position compound, with position defined in terms of proximity to a distinctive visual landmark, was used; and, in Experiment 4, an odor-position compound was used. In each of the first three experiments, the blocking group responded less than did the control group in a subsequent test with X; in the fourth experiment, the two groups did not differ. The results are in accord with expectations based on those of previous experiments with honeybees in which the independence assumption was found to hold for intermodal compounds but not for intramodal compounds. 相似文献
8.
In the blocking phase of three experiments, rats had to find a submerged platform beneath a spherical landmark in one corner
of a triangular pool. Prior to this treatment, they were required to find the platform relative to either a sphere above it
(blocking groups) or a rod attached to it (control groups). The position of the platform changed from trial to trial for the
initial training. The sphere did not restrict learning about the geometric cues provided by the triangular arena in the blocking
phase when 12 sessions of initial training took place in either the triangular (Experiment 1) or a circular (Experiment 3)
pool. Blocking was observed, however, after 24 sessions of initial training in either the triangular (Experiment 2) or the
circular (Experiment 3) pool. Thus, blocking of geometric cues by a landmark is possible after extended initial training with
the blocking cue. 相似文献
9.
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
10.
In three between-groups blocking experiments with rats, two concurrent and one forward, several common control procedures
were employed: Reinforced trials with the putative blocking stimulus were either omitted entirely (Kamin control), replaced
by unsignaled reinforcements (Wagner control), or replaced by reinforced trials with a different stimulus (C1 control). In
each experiment, parallel treatments with the target stimulus absent during training served to examine the possibility that
differential responding in tests with the target stimulus might be traced solely to differential exposure to the nontarget
stimuli. In Experiment 1, responding by a concurrent blocking group during the test was no different than responding by a
Kamin control group, and responding by a Wagner control group was greater than that of either of the other groups—a pattern
of results, mirrored in the performance of the target-absent groups, that could be attributed to the elevation of contextual
excitation by unsignaled reinforcement. In Experiment 2, responding in the test by a concurrent blocking group was no different
than that by a C1 control group. In Experiment 3, a finding of less responding by a forward blocking group than by a C1 control
group when the target stimulus was present during training, but not when it was absent, provided plausible evidence of blocking. 相似文献
11.
Pigeons obtained food by pecking at an unmarked target location on a video screen equipped with a touch-sensitive frame. The target area was located near the top edge of the screen in Experiment 1 and near the left edge of the screen in Experiment 2. On baseline trials, a graphic landmark was located below and left of the target (Experiment 1) or below and right of the target (Experiment 2). In both experiments, baseline search distributions showed a single peak and were roughly symmetrical about the target area in both horizontal and vertical dimensions. On occasional test trials, the landmark was shifted horizontally, vertically, or diagonally by 1.5 cm or 3 cm. In both experiments, landmark shifts in the dimension parallel to the nearest edge produced systematic shifts in the peak place of search. Landmark shifts in the dimension perpendicular to the nearest edge produced inconsistent (Experiment 1) or relatively small (Experiment 2) shifts in peak place. The magnitude of the behavioral shift was always less than the magnitude of the landmark shift and was not consistently greater when the landmark was shifted by 3 cm than when it was shifted by 1.5 cm. These results demonstrated that pigeons can accurately locate an unmarked target area in a two-dimensional vertical arena and that their use of landmarks for spatial localization is similar in several respects to that found in open-field spatial search tasks. 相似文献
12.
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
13.
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
14.
The ability to use the relations between visible landmarks to locate nonvisible goals (allocentric spatial coding) underlies success on a variety of everyday spatial orientation problems. Little is known about the development of true relational coding in infancy. Ninety-six 6-, 8.5- and 12-month-old infants were observed in a peekaboo paradigm in which they had to turn to a target location after displacement to a novel position and direction of facing. In a landmark condition, the target position was located between two landmarks, contrasted with a control condition in which no distinctive landmarks were provided. Six-month-old infants performed poorly in both conditions, 8.5-month-olds were significantly better with the landmarks, and 12-month-olds solved the task with or without landmarks. A follow-up study confirmed that the 8.5-month-olds used both landmarks to solve the task. This demonstration of allocentric spatial coding in 8.5-month-old infants shows earlier competence than that found in previous work in which only infants at the end of the first year were able to use landmarks relationally. 相似文献
15.
Two groups of Clark’s nutcrackers were trained to find buried seeds whose location was defined by a constant angle from two landmarks whose interlandmark distance and position in the room varied across trials. The first group had a landmark array that was always placed in the same orientation with respect to the walls, allowing the animals to use both relative and absolute bearings. The second group had a landmark array that rotated across trials so that only relative bearings could be used to locate the seeds. The birds in each group learned the task and transferred to new interlandmark distances both within and beyond the range of training distances. Results from these experiments indicate that nutcrackers can learn a geometric relationship that relies exclusively on relative bearings even though the use of absolute bearing yields more efficient search. 相似文献
16.
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
17.
Pigeons learned to respond at one spatial position when a pair of stimuli matched and at a different spatial position when they mismatched. All birds were then transferred to novel stimuli on an orthogonal dimension. For the positive-transfer group, the correct positions for matching and mismatching stimuli remained as they were during training. For the negative-transfer group, the correct positions were reversed. In Experiment 1, the birds were trained with shape stimuli and transferred to hue stimuli. Significant group differences were found, in spite of considerable stimulus-specific learning. In Experiment 2, when the same birds (counterbalanced for Experiment 1 transfer group) were transferred to steady-intermittent stimuli, even larger group differences were found. The data indicate that pigeons have some capacity for representing the concepts “same” and “different” with arbitrary stimuli (i.e., symbols). The data further suggest that distinctions that have been made between matching/oddity transfer tasks and same/different tasks may be procedural rather than conceptual. 相似文献
18.
Extinction-induced attenuation of single-phase and two-phase blocking was examined with rats in a conditioned lick-suppression
task. In Experiment 1, which compared the effectiveness of single- and two-phase blocking, it was found that single-phase
blocking was facilitated by the initiation of training with an A-US trial rather than an AX-US trial. Single-phase (but not
two-phase) blocking was attenuated as a result of 200 extinction trials with the blocking stimulus (Experiment 2). Experiment
3 revealed recovery from two-phase blocking after 800 extinction trials with the blocking stimulus. Recovery from both types
of blocking was specific to the blocked CS trained in compound with the extinguished stimulus (Experiment 4). This is the
first article to report that the blocking deficit can be reversed by extinguishing the blocking stimulus. These results are
discussed in light of acquisition models (i.e., retrospective revaluation) and expression models (i.e., the comparator hypothesis). 相似文献
19.
Rats were trained in a triangular water maze in which a compound of geometric and landmark cues indicated the position of a submerged platform. Rats that then underwent revaluation of the geometric cues in the absence of the landmarks subsequently failed to discriminate between the landmarks. In contrast, those animals that received geometry training consistent with their previous experience of the geometry–landmark compound continued to discriminate the landmark cues. The experiment showed that within-compound associations had formed between the geometry and landmarks, and that representations of absent geometric cues could be evoked via presentation of the landmark cues alone. We argue that these evoked representations of the absent geometry cues can counteract any overshadowing of the landmark by geometry cues, and may sometimes result in potentiation. The results of this study do not support theories of cue-competition failure based on independent cue processing, but remain readily explicable by appeal to an account based on within-compound associations. 相似文献
20.
Control exerted by different categories of spatial information on short-distance return to shelter by young cockroach larvae and weighting of different information sources in conflict situations were investigated. In the absence of landmark cues, larvae preferred information given by path integration with kinesthetic cues over scototactic cues. When two landmark cues with a particular angular position between them were shifted 180°, larvae relied on these learned landmarks provided that their relative angular position was kept unchanged. When only one of the landmark cues was shifted 180°, larvae preferred to use the path integration system. When larvae could not use path integration cues, a modified configuration of the landmarks disturbed them. They relied on scototactic cues, although some seemed to rely on either one of the landmarks to find their shelter. Cockroaches could change the order of importance that they normally attributed to certain classes of spatial information (in increasing order: scototaxis, path integration, and learned visual landmarks) in relation to ongoing conditions. 相似文献