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1.
The Transition to Reaching: Mapping Intention and Intrinsic Dynamics   总被引:9,自引:0,他引:9  
The onset of directed reaching demarks the emergence of a qualitatively new skill. In this study we asked how intentional reaching arises from infants' ongoing, intrinsic movement dynamics, and how first reaches become successively adapted to the task. We observed 4 infants weekly in a standard reaching task and identified the week of first arm-extended reach, and the 2 weeks before and after onset. The infants first reached at ages ranging from 12 to 22 weeks, and they used different strategies to get the toy. 2 infants, whose spontaneous movements were large and vigorous, damped down their fast, forceful movements. The 2 quieter infants generated faster and more energetic movements to lift their arms. The infants modulated reaches in task-appropriate ways in the weeks following onset. Reaching emerges when infants can intentionally adjust the force and compliance of the arm, often using muscle coactivation. These results suggest that the infant central nervous system does not contain programs that detail hand trajectory, joint coordination, and muscle activation patterns. Rather, these patterns are the consequences of the natural dynamics of the system and the active exploration of the match between those dynamics and the task.  相似文献   

2.
Kinetic contours in infants' visual perception   总被引:2,自引:0,他引:2  
3-month-old infants' perception of "camouflaged" forms that are only visible when moving was studied. Displays were used in which figure and ground had an identical random dot texture, and no edge indicated the form of the figure. The form was invisible when stationary. Discrimination of 2 different forms was tested (a) when the forms were visible only through motion, and (b) when the forms appeared as stationary white figures on black ground. The babies discriminated the forms in both conditions. Furthermore, when infants were habituated to one of the moving forms and subsequently presented with the same and a new static form, they looked longer at the new form. This indicates that they recognized the static form as either the same or different from the moving form seen before, although the optical sources of information were completely different. At 3 months, infants can therefore effectively use kinetic information to organize the visual input in higher-order structures.  相似文献   

3.
Associations between infants' transition to walking and object activities were examined. Fifty infants were observed longitudinally during home observations. At 11 months, all infants were crawlers; at 13 months, half became walkers. Over age, infants increased their total time with objects and frequency of sharing objects with mothers. Bidirectional influences between locomotion and object actions were found. Walking was associated with new forms of object behaviors: Walkers accessed distant objects, carried objects, and approached mothers to share objects; crawlers preferred objects close at hand and shared objects while remaining stationary. Earlier object activities predicted walking status: Crawlers who accessed distant objects, carried objects, and shared objects over distances at 11 months were more likely to walk by 13 months.  相似文献   

4.
Perception of the manner in which objects may be grasped was examined in a series of experiments with adults and 10-month-old infants; visuomotor adjustment in hand orientation before making contact with objects served as the index throughout. In the first experiment, infants modified their hand orientation to match more closely the long axis of an object. They did so even though the target object could have been grasped by either end with hands oriented orthogonally to the long axis of the object. In two subsequent experiments involving reaching through narrow apertures to grasp the target, anticipatory adjustments in hand posture were evident for adults but not for infants. However, anticipatory adjustments by infants, sometimes appropriate and sometimes inappropriate, were made when the object was of such a size that it could neither be grasped nor retrieved through the aperture. In the final experiment, infants directed their hands first toward a handle, the only graspable part of an object, and oriented their hands so as to be nearly parallel with it prior to contact. This was the only orientation in which a grasp was possible. It was concluded that infants at 10 months respond more appropriately to object properties than to surface apertures that place limitations on how an object may be grasped.  相似文献   

5.
Infants parse dynamic action   总被引:6,自引:0,他引:6  
As observers of human behavior, infants are faced with a complex flow of motion in which pauses are rare and only occasionally coincide with boundaries between intentional actions. Two studies investigated whether, despite such complexity, 10- to 11-month-old infants (N = 16 for each study) possess skills for parsing ongoing behavior along boundaries correlated with the initiation and completion of intentions. After being familiarized with digitized sequences of continuous everyday action, infants showed renewed interest in test versions in which motion paused in the midst of an actor's pursuit of intentions (interrupting test videos). In contrast, pauses that suspended motion at intention boundary points (completing test videos) sparked no such renewed interest on infants' part. Moreover, basic salience differences between the two types of test videos were not the source of infants' increased interest when intentions were interrupted (Study 2). These findings demonstrate that infants readily detect disruptions of the structure inherent in intentional action, and hence parse ongoing behavior with respect to such structure. Such parsing skill is likely a prerequisite to the development of genuine intentional understanding.  相似文献   

6.
Diamond A  Lee EY 《Child development》2000,71(6):1477-1494
Infants of 5 to 6 months of age can retrieve a free-standing object, but fail to retrieve the same object from atop a slightly larger object. The accepted explanation has been that the infants do not understand that an object continues to exist independently when placed upon another. Predictions based on that explanation were tested against the hypothesis that infants' problem consists of lack of precision in visually guided reaching and lack of ability to inhibit reflexive reactions to touch. Twelve infants each at 5 and 7 months of age were tested on 16 trials. More 5-month-olds succeeded, in less time, and with fewer touches to an edge of the base, on trials more forgiving of an imprecise reach than on less forgiving trials. Success in retrieving objects close in size and fully contiguous with their bases was seen even at 5 months when the demands on skill in reaching were reduced. It is proposed that when 5-month-old infants fail to retrieve one object placed upon another, it is not because of a lack of conceptual understanding, but because they lack the skill to reach to the top object without accidentally touching an edge of the base en route.  相似文献   

7.
Auditory-visual perception of changing distance by human infants   总被引:1,自引:0,他引:1  
2 studies examined 5-month-old infants' sensitivity to auditory-visual specification of distance and direction of movement. In 1 experiment, infants were presented successively with 2 filmed events--1 of an automobile approaching, and the other of the same automobile driving away. A soundtrack that increased or decreased in amplitude was played along with each film, either in a match or mismatch condition. Infants did not show differential looking patterns related to the match or mismatch of auditory and visual information. In a second experiment, infants were tested using a paired preference technique. The films were shown side-by-side along with a single soundtrack appropriate to 1 of them. Looking time was monitored as before. These infants demonstrated visual preferences for the sound-matched films, evidently detecting the relationship between auditory and visual information when this procedure was used.  相似文献   

8.
Despite hundreds of studies describing infants' visual exploration of experimental stimuli, researchers know little about where infants look during everyday interactions. The current study describes the first method for studying visual behavior during natural interactions in mobile infants. Six 14-month-old infants wore a head-mounted eye-tracker that recorded gaze during free play with mothers. Results revealed that infants' visual exploration is opportunistic and depends on the availability of information and the constraints of infants' own bodies. Looks to mothers' faces were rare following infant-directed utterances but more likely if mothers were sitting at infants' eye level. Gaze toward the destination of infants' hand movements was common during manual actions and crawling, but looks toward obstacles during leg movements were less frequent.  相似文献   

9.
This study compared the relative contributions of growing body dimensions, age, and walking experience in the development of walking skill in 9- to 17-month-old infants (N = 210), 5-6-year old kindergartners (N = 15), and college students (N = 13). Kinematic measures derived from participants' footprints showed characteristic improvements in walking skill. As children became bigger, older, and more experienced, their steps became longer, narrower, straighter, and more consistent. Improvements reflected a narrowing base of support and increasing control over the path of progression. Although both infants' age and the duration of their walking experience contributed to improvements in walking skill, experience was the stronger predictor. This finding suggests that practice is the more important developmental factor for helping infants to conquer their weak muscles and precarious balance.  相似文献   

10.
Is Visually Guided Reaching in Early Infancy a Myth?   总被引:4,自引:0,他引:4  
The issue examined was whether infants require sight of their hand when first beginning to reach for, contact, and grasp objects. 7 infants were repeatedly tested between 6 and 25 weeks of age. Each session consisted of 8 trials of objects presented in the light and 8 trials of glowing or sounding objects in complete darkness. Infants first contacted the object in both conditions at comparable ages (mean age for light, 12.3 weeks, and for dark, 11.9 weeks). Infants first grasped the object in the light at 16.0 weeks and in the dark at 14.7 weeks, a nonsignificant difference. Once contact was observed, infants continued to touch and grasp the objects in both light and dark throughout all sessions. Because infants could not see their hand or arm in the dark, their early success in contacting the glowing and sounding objects indicates that proprioceptive cues, not sight of the limb, guided their early reaching. Reaching in the light developed in parallel with reaching in the dark, suggesting that visual guidance of the hand is not necessary to achieve object contact either at the onset of successful reaching or in the succeeding weeks.  相似文献   

11.
音乐是发展孩子想象力、创造力,促进个性发展的有效手段。在音乐教育中我们要以幼儿为本,充分发挥幼儿的自主性,要改变以往使艺术成为技能训练和表演的功能。我们可以让幼儿通过倾听音乐、感受旋律、表现音乐,体验快乐情绪;通过让幼儿创编歌词、创编动作、创编节奏,充分发挥幼儿的创造潜能;通过培养幼儿的协作意识、规则意识、良好情感,促进幼儿综合素质的提高。  相似文献   

12.
L G Craton  A Yonas 《Child development》1988,59(6):1522-1529
We investigated infants' sensitivity to a recently discovered kinetic depth cue, boundary flow. 5-month-old infants viewed computer-generated displays in which the relation between the motion of a boundary, indicating an edge, and 2 regions of dots on either side of the boundary, indicating surfaces, provided the only information specifying the order of the 2 surfaces in depth. Infants showed a significant reaching preference for the apparently nearer region of the display. Since previous research has demonstrated that infants reach more frequently for the nearer of 2 surfaces, this result indicates that 5-month-old infants are sensitive to boundary flow information for depth at an edge.  相似文献   

13.
This longitudinal study investigated the effect of experience with tactile stimulation on infants' ability to reach to targets on the body, an important adaptive skill. Infants were provided weekly tactile stimulation on eight body locations from 4 to 8 months of age (N = 11), comparing their ability to reach to the body to infants in a control group who did not receive stimulation (N = 10). Infants who received stimulation were more likely to successfully reach targets on the body than controls by 7 months of age. These findings indicate that tactile stimulation facilitates the development of reaching to the body by allowing infants to explore the sensorimotor correlations emerging from the stimulation.  相似文献   

14.
Differential facial responses to four basic tastes in newborns   总被引:6,自引:0,他引:6  
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15.
The present study assessed the development of reaching for objects positioned in front of the contralateral shoulder. In particular, it examined how the development of crossing the midline is related to the development of bimanual reaching. Twenty infants were observed longitudinally at 12, 18, and 26 weeks of age while reaching for two balls (3 cm and 8 cm in diameter) located at three positions (ispsilateral, midline, and contralateral). The reaches were analyzed from video recordings. With age, the infants increasingly adapted the number of hands used to the size of the object. The number of reaches crossing the body midline increased with age. Furthermore, the majority of the midline crossings were part of two-handed reaches for the large ball and occurred at or after onset of bimanual reaching. Together, these findings strongly suggest that the development of crossing the body midline emerges in the context of bimanual reaching. It was concluded that the need to grasp a large ball positioned contralaterally with two hands induces midline crossing. Hence, the development of midline crossings is not exclusively dependent on organismic constraints (e.g., the maturation of hemispheric connections), but rather on their interaction with environmental constraints (e.g., object size).  相似文献   

16.
The claim that very young infants can imitate rests largely on reports that infants match adult displays of mouth opening (MO) and tongue protrusion (TP). Recent reviews suggest that only tongue protruding is reliably matched by young infants. This study tests the proposal that infants' "imitation" of tongue protruding reflects a coincidental match between a sight that infants find interesting and a behavior by which infants express interest. In Study 1, 4-week-old infants who looked longer at a nonsocial light display also produced TPs at higher rates than infants showing less interest. In Study 2, 4-week-old infants showed more interest in (looked longer at) a tongue-protruding adult face than a mouth-opening face. Study 3 tracked 2 infants' responses to interesting objects for several weeks before and after the onset of manual reaching. Both infants produced tongue protrusions in response to objects within reach before but not after reaching developed. Together, the results of the 3 studies suggest that infants' tongue protrusions in response to a tongue-protruding adult reflect very early attempts at oral exploration of interesting objects.  相似文献   

17.
This experiment evaluated the role of visual input about the location of a target object and the location of the hand in reaching by infants and adults. 5- and 9-month-old infants were presented with illuminated toys to reach for in a dark room. On no-switch trials, the toy remained illuminated throughout the infant's reach, whereas on switch trials the first-lit toy was replaced during the reach by a second-lit toy at a different position. On approximately half of the trials of each type a luminescent marker was attached to the reaching hand. Adult subjects (tested without the hand marker) fully compensated to the second-lit toy on switch trials, during a second reaching segment. On switch trials, 9-month-olds partially adjusted to the second-lit toy when wearing the hand marker and did not adjust without it. On no-switch trials, 9-month-olds reached just as accurately with or without the hand marker. 5-month-olds were generally inaccurate in their reaching and were unaffected by the presence or absence of the hand marker. The findings suggest that during the development of reaching there is an increase in visual guidance during the approach phase of reaches.  相似文献   

18.
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   

19.
20.
This study examined European American and Hispanic American mothers' multimodal communication to their infants (N = 24). The infants were from three age groups representing three levels of lexical-mapping development: prelexical (5 to 8 months), early-lexical (9 to 17 months), and advanced-lexical (21 to 30 months). Mothers taught their infants four target (novel) words by using distinct objects during a semistructured play episode. Recent research suggests that young infants rely on temporal synchrony to learn syllable-object relations, but later, the role of synchrony diminishes. Thus, mothers' target and nontarget naming were coded for synchrony and other communication styles. The results indicated that mothers used target words more often than nontarget words in synchrony with object motion and sometimes touch. Thus, "multimodal motherese" likely highlights target word-referent relations for infants. Further, mothers tailored their communication to infants' level of lexical-mapping development. Mothers of prelexical infants used target words in synchrony with object motion more often than mothers of early- and advanced-lexical infants. Mothers' decreasing use of synchrony across age parallels infants' decreasing reliance on synchrony, suggesting a dynamical and reciprocal environment-organismic relation.  相似文献   

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