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1.
The robustness of infant haptic memory was assessed in terms of its capacity to withstand either a brief delay or potential retroactive "interference" from other haptic input. 48 infants (mean age 8 months) were familiarized haptically to a small cube or sphere with smooth or rough surface texture and subsequently tested for recognition of the shape and texture of this stimulus in terms of the relative level of haptic response to 3 test stimuli, comprising the familiar stimulus, a new-shape stimulus, and a new-texture stimulus. The test stimuli were presented ( a ) immediately, ( b ) after a 5-min delay, or ( c ) after a second familiarization or "interference" phase involving another haptic stimulus different in shape and texture to the first. The infants demonstrated recognition of shape and texture in the No Delay condition, of shape and (marginally) of texture in the Delay condition, but only of texture in the Interference condition. The greater susceptibility of shape to interference was considered in terms of the degree of similarity among the shapes employed in the study.  相似文献   

2.
40 10-month-old infants were given 2 min to explore tactually an object in a totally darkened room. Subsequently, during a 2-min test trial in the dark, half of the infants were given the same object and half were given a novel shape. Infants presented with the novel shape evidenced significantly longer durations of manipulation than infants presented with familiar forms. Infants are thus capable of tactually discriminating novel and familiar shapes in the absence of vision and demonstrate a preference for novelty within the tactual modality.  相似文献   

3.
After training with a variable-interval schedule of positive reinforcement, pigeons were tested for stimulus generalization along the hue dimension. For one group, the stimulus was located on the response key. For a second group, the stimulus was located on a surface adjacent to the response key. The stimulus-on-key group produced the typical steep gradients normally found with hue stimuli; the stimulus-off-key group produced flat gradients. After discrimination training between the presence and absence of the hue stimulus, both groups produced decremental gradients. In a second experiment, naive pigeons were trained to peck a transparent key with the stimulus surface located approximately 3.8 cm behind the key. When tested for generalization, the hue gradients were decremental. The results suggest that location of the stimulus in the line of sight with pecking is a necessary condition for stimulus control by hue after nondifferential training.  相似文献   

4.
The purpose of this experiment was to test the theory of Lubow, Rifkin, and Alek (1976) concerning the effects of stimulus preexposure on later learning. This hypothesis predicts that conditioning will occur faster when either the stimulus or the testing environment is novel relative to the other than when the stimulus and the environment are equally novel or equally familiar. The theory was tested in a taste aversion conditioning paradigm in which groups of rats were presented with either the familiar (preexposed) solution or the novel nonpreexposed solution, in either the familiar or the novel environment. Conditioning was affected by the novelty of both the stimulus and the environment, with novel stimuli enhancing learning and novel environments retarding it. However, no interaction between stimulus and environmental novelty was evident, and thus Lubow’s hypothesis was not confirmed.  相似文献   

5.
Electrophysiological correlates of infant recognition memory   总被引:4,自引:0,他引:4  
Event-Related Potentials were recorded from 6-month-old infants in order to examine the electrophysiological correlates of recognition memory. In 1 study, infants were shown 1 face briefly, followed by the same face presented with high probability, and a novel face presented with low probability. 2 components were observed that distinguished between the novel and familiar events. Differences between these components in latency, polarity, and scalp topography led to the suggestion that 2 processes were involved in recognizing the stimuli. In a second study infants were again presented with 1 face briefly, followed by the same face and a novel face presented with equal probability. 1 component at central scalp distinguished between the novel and familiar events. In a third study, infants were simply presented with 2 previously unseen faces equally often. Infants responded as if the faces were identical, suggesting that previous experience with 1 stimulus directs infants' attention to the novel stimulus during the test portion of the task. The extent to which the observed responses reflect the updating of working memory is discussed, as is the extent to which infants' electrophysiological response to stimulus novelty and uncertainty resembles the adult's.  相似文献   

6.
4-month-old infants were tested for sensitivity to kinetic and binocular information for 3-dimensional-object shape. The study included 2 tests: a test for sensitivity to binocular disparity and a shape perception test. The disparity sensitivity test used a preferential looking procedure developed by Held, Birch, and Gwiazda. On the basis of the results of this test, infants were assigned to disparity-sensitive and disparity-insensitive groups. In the shape perception test, a "transfer-across-depth-cues" method was employed. Infants were habituated to a rotating object whose shape was specified by kinetic information and were then presented with stationary stereograms specifying the same object and a novel-shaped object. The disparity-sensitive infants looked significantly longer at the novel object than at the familiar object, whereas the disparity-insensitive infants showed no difference in looking time to the novel and the familiar objects. The results indicate that disparity-sensitive 4-month-old infants can perceive 3-dimensional-object shape from kinetic and binocular depth information.  相似文献   

7.
Perception of kinetic illusory contours by 2-month-old infants was explored with sparse random-dot displays depicting an illusory shape against a background. In Experiment 1, 24 infants were habituated to a shape specified by accretion and deletion of background texture and relative motion, and exhibited a novelty preference when presented with luminance-defined familiar and novel shapes. Subsequent experiments explored kinetic cues in isolation. In Experiment 2 (n = 24), relative motion information was removed, leaving accretion and deletion of texture and luminance cues, and in Experiment 3 (n = 24), only relative motion information was available. In both these experiments the novelty preference obtained in Experiment 1 was replicated. Results from a control condition (n = 12) mitigated against the likelihood of an inherent preference for either of the test shapes. These findings reveal an early capacity to perceive shape solely from kinetic information, and suggest a mechanism geared toward spatiotemporal boundary formation that is functional shortly after birth. Theories of development of edge and motion discrimination are discussed.  相似文献   

8.
This study evaluated the interactive effects of endogenous and exogenous influences on infants' attention allocation by assessing the role of target familiarity on distraction latency during object exploration. In Experiment 1 (N = 54), infants' distraction latencies as they investigated both familiar toys (ones they previously had seen in a familiarization procedure) and novel toys (ones they had not seen in the familiarization procedure) were assessed longitudinally at 6.5 and 9 months of age. In Experiment 2 (N = 32), infants' distraction latencies were assessed at either 6.5 or 10 months as they investigated either familiar or novel targets. In both experiments, older infants, but not younger infants, exhibited longer latencies as they investigated novel toys as compared with their latencies as they investigated familiar toys. These results are discussed in terms of developmental changes in the interactive effects of endogenous and exogenous factors controlling attention allocation.  相似文献   

9.
Pigeons were first trained on many-to-one delayed matching in which pairs of hue and line-orientation samples were associated with individual comparison stimuli. They were then trained to match two of the original samples (either hues or line orientations) to new comparisons, after which 2-sec delays were inserted between the samples and comparisons. In testing, the remaining samples were presented as interpolated stimuli during the delays. When the interpolated stimulus had been associated with the same comparison as the sample in many-to-one matehing, performance was significantly more accurate than when it had been associated with a different comparison. This finding adds to the evidence that samples sharing common comparison associations are commonly coded.  相似文献   

10.
We report the first successful demonstration of a simultaneous, two-itemsame-different (S/D) discrimination by 6 pigeons, in which nonpictorial color and shape stimuli were used. This study was conducted because the majority of recently successful demonstrations of S/D discrimination in pigeons have employed displays with more than two items. Two pairs of stimulus items were simultaneously presented on a touch screen equipped computer monitor. Pigeons were reinforced for consistently pecking at either thesame (i.e., identical) or thedifferent (i.e., nonidentical) pair of items. These pairs were created from combinations of simple colored shapes drawn from a pool of six colors and six shapes. After acquiring the discrimination with item pairs that differed redundantly in both the shape and the color dimensions, the pigeons were tested for transfer to items that varied in only one of these dimensions. Although both dimensions contributed to the discrimination, greater control was exhibited by the color dimension. Most important, the discrimination transferred in tests with novel colored, shaped, and sized items, suggesting that the mechanisms involved were not stimulus specific but were more generalized in nature. These results suggest that the capacity to judge S/D relations is present in pigeons even when only two stimuli are used to implement this contrast.  相似文献   

11.
Conditioning-specific reflex modification occurs when an unconditioned response is modified in theabsence of the conditioned stimulus as a result of pairings of the conditioned stimulus and an unconditioned stimulus. In two experiments, we assessed conditioning-specific reflex modification in either a novel context (Experiment 1) or a context different from, but equally familiar in relation to, the training context (Experiment 2). Conditioning-specific reflex modification did not demonstrate sensitivity to a novel context but did demonstrate sensitivity to a change in familiar context. The data cannot be explained by unconditioned stimulus preexposure, overtraining, or context insensitivity. The results suggest that conditioning-specific reflex modification models normal stress and may be used to evaluate theories of and treatments for posttraumatic stress disorder.  相似文献   

12.
Although it is often acknowledged that classification exists in the first year of life, it has been suggested that infants are capable only of implicit categorization, recognizing that something is or is not familiar. In contrast, older children are thought to compare the stimuli or objects they categorize and to explicitly equate different category members. 2 habituation experiments were conducted in an attempt to determine whether 10-month-old infants are capable of explicit categorization. The approach taken was to insert nonmembers into the familiarization sequence in a categorization task. The nonmembers were designed so as to have a predictable effect on infants' performance whether or not these stimuli were included as infants processed the categorical information. The results suggest that infants do explicitly equate category members. Infants appeared to disregard the nonmembers in the familiarization sequence, basing their categorization response instead on the set of instances that were "the same sort of thing."  相似文献   

13.
The ability of 7- and 10-month-old infants to generalize their discrimination of facial expressions lacking featural consistency was investigated in a series of 4 experiments. Infants were habituated to models posing either prototypically positive displays (e.g., happy expressions) or positive expression blends (e.g., mock surprise). They were then tested for their ability to recognize a positive expression on the face of a novel model and to discriminate positive and negative facial expressions. Only in Experiment 1, in which infants were familiarized to a mix of happy and surprised facial expressions, did 10-month-olds demonstrate generalized discrimination of positive affect. When positive blends or happy expressions alone served as familiarization stimuli, both 7- and 10-month-old infants failed to dishabituate to a change in affective tone. 7-month-olds, in particular, showed consistent recovery of looking to the introduction of novel models. The pattern of results suggests that it is not until sometime after 7 months of age that dependence on the presence of expression-specific features for affect recognition and discrimination diminishes. By 10 months of age, however, infants are beginning to recognize the affective similarity of familiar positive facial expressions.  相似文献   

14.
Holistic face processing was investigated in newborns, 3-month-old infants, and adults through a modified version of the composite face paradigm and the recording of eye movements. After familiarization to the top portion of a face, participants (N = 70) were shown 2 aligned or misaligned faces, 1 of which comprised the familiar top part. In the aligned condition, no visual preference was found at any group age. In the misaligned condition, 3-month-olds preferred the face stimulus with the familiar top part, adults preferred the face stimulus with the novel one, and newborns did not manifest any visual preference. Results revealed that both infants' and adults' eye movements may be affected by holistic face information and demonstrated holistic face processing in 3-month-olds.  相似文献   

15.
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   

16.
2 experiments assessed the effects of prior noncontingent or familiarization experience on subsequent operant conditioning (kick-produced mobile movement) in young infants. In Experiment 1, infants received either long- or short-term noncontingent exposure to their own rotating mobile or simply viewed this mobile for several days while it remained motionless. In Experiment 2, long-term exposure was provided by the same novel mobile used for subsequent training. In both experiments, prior noncontingent experience did not interfere with subsequent conditioning. In Experiment 2, however, simple long-term familiarization with the training mobile precluded "evidence" of learning. The results indicated that infants develop expectancies regarding how stimuli occurring in particular contexts should behave based on their prior experiences with these stimuli.  相似文献   

17.
Children often perseverate, repeating prior behaviors when inappropriate. This work tested the roles of verbal labels and stimulus novelty in such perseveration. Three-year-old children sorted cards by one rule and were then instructed to switch to a second rule. In a basic condition, cards had familiar shapes and colors and both rules were stated explicitly. In an uninformative-label condition, cards had familiar shapes and colors, but the first rule was not stated explicitly. In a novel-stimuli condition, both rules were stated explicitly but stimuli were novel on the first sorting dimension. More children switched to the second rule in the uninformative-label and novel-stimuli conditions than in the basic condition. Implications for theories of cognitive flexibility are discussed.  相似文献   

18.
To examine whether children (mean age 34 months) can fast map and extend novel action labels to actions for which they do not already have names, the comprehension of familiar and novel verbs was tested using colored drawings of Sesame Street characters performing both familiar and unfamiliar actions. Children were asked to point to the character "verbing," from among sets of 4 drawings. With familiar words and actions, children made correct choices 97% of the time. With novel action words, children performed at levels mostly significantly above chance, selecting a previously unlabeled action or another token of a just-names action. In a second, control experiment children were asked to select an action from among the same sets of 4 drawings, but they were not given a novel action name. Here children mainly demonstrated performance at levels not significantly different from chance, showing that the results from the main experiment were attributable to the presence of a word in the request. Results of these studies are interpreted as support for the availability of principles to ease verb acquisition.  相似文献   

19.
This study examined the influence of object labels and shape similarity on 16- to 21-month-old infants' inductive inferences. In three experiments, a total of 144 infants were presented with novel target objects with or without a nonobvious property, followed by test objects that varied in shape similarity to the target. When objects were not labeled, infants generalized the nonobvious property to test objects that were highly similar in shape (Experiment 1). When objects were labeled with novel nouns, infants relied both on shape similarity and shared labels to generalize properties (Experiment 2). Finally, when objects were labeled with familiar nouns, infants generalized the properties to those objects that shared the same label, regardless of shape similarity (Experiment 3). The results of these experiments delineate the role of perceptual similarity and conceptual information in guiding infants' inductive inferences.  相似文献   

20.
This study investigated the ability of preterm infants to learn an object shape with one hand and discriminate a new shape in the opposite hand (without visual control). Twenty-four preterm infants between 33 and 34 + 6 gestational weeks received a tactile habituation task with either their right or left hand followed by a tactile discrimination task in the opposite hand. The results confirmed that habituation occurred for both shapes and both hands. Infants subsequently held the novel shape longer in the opposite hand. The results reveal that preterm infants are capable of intermanual transfer of shape information. In spite of the immaturity of the corpus callosum in preterm infants, its development seems to be sufficient to allow some transfer of information between both hands.  相似文献   

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