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1.
The role of vision was examined as infants prepared to grasp horizontally and vertically oriented rods. Hand orientation was measured prior to contact to determine if infants differentially oriented their hands relative to the object's orientation. Infants reached for rods under different lighting conditions. Three experiments are reported in which (1) sight of the hand was removed (N = 12), (2) sight of the object was removed near the end of the reach (N = 40, including 10 adults), and (3) sight of the object was removed prior to reach onset (N = 9). Infants differentially oriented their hand to a similar extent regardless of lighting condition and similar to control conditions in which they could see the rod and hand throughout the reach. In preparation for reaching, infants may use the current sight of the object's orientation, or the memory of it, to orient the hand for grasping; sight of the hand had no effect on hand orientation. 相似文献
2.
Is Visually Guided Reaching in Early Infancy a Myth? 总被引：4，自引：0，他引：4
Rachel K. Clifton Darwin W. Muir Daniel H. Ashmead Marsha G. Clarkson 《Child development》1993,64(4):1099-1110
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
3.
The organization of infants' reaching skill for stationary and moving targets was examined. While 58 term, healthy infants at 5.5, 8.5, and 11.5 months of age reached for and grasped a cloth-covered dowel, their reaches were videotaped for later slow-motion analysis. Analyses addressed infants' anticipatory adjustment of hand alignment, use of information from spinning and oscillating targets to update ongoing reaches, and ability to capture targets moving in depth. Infants at all ages made anticipatory adjustments of hand alignment, although the effectiveness of these adjustments improved with age. Regardless of age, infants also used dynamic information from spinning and oscillating targets to update ongoing reaches, but the way infants used this information was related to age. Developmental constancy characterized infants' reaches for approaching targets. By observing infants' reaches for stationary, spinning, and approaching targets, the study expands the range of conditions under which adaptive reaching skill has been examined and provides insight into the roles of anticipation and updating in the development of early manual skill. 相似文献
4.
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
5.
The development of the ability to extend the hand across the body midline to contact a visually presented object was examined in 48 normal, full-term, 9--20-week infants. One of the infant's arms was restrained while the behavior of the contralateral, unrestrained arm was observed. Results indicate that infants can first contact objects placed in front of the ipsilateral shoulder, then at the body midline, and later in front of the contralateral shoulder. Between 9 and 17 weeks, success at contacting objects at the midline progressed from 33% to 93%. During this interval, the success in contacting objects presented in front of the contralateral shoulder increased from 0% to 71%. By 18--20 weeks, all infants contacted objects in all three positions. These findings indicate that visually directed hand extension and reaching skills progress from the ipsilateral to include the bilateral and later the contralateral domains. The results are considered in regard to the development of bilateral coordination and complementarity. 相似文献
6.
Intermanual transfer of shapes in preterm human infants from 33 to 34 + 6 weeks postconceptional age
Lejeune F Marcus L Berne-Audeoud F Streri A Debillon T Gentaz E 《Child development》2012,83(3):794-800
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
7.
The ability of infants aged 8–12 months to coordinate their arm and trunk movements to contact an object located in different positions was investigated in 2 experiments. In the first, 8- and 10-month-old infants reached for near objects but both reached and leaned for more distant ones indicating that they perceived that forward leaning extends the range of contact beyond that of reaching alone. In addition, arm and trunk movements were initiated simultaneously; visual information concerning object distance was sufficient to activate an integrated reaching-and-leaning response. Object distances were increased and a mechanical aid was provided on half the trials in the second experiment with 10- and 12-month-old infants. For both age groups the degree of leaning was reduced for objects that were out of reach without the aid. Only older infants were able to use the aid to extend partially their range of contact. Overall the results support the conclusions that, by at least 8 months, infants perceive that leaning extends their effective reaching space; by 10 months they perceive the limits within which reaching together with leaning is likely to be effective; and by 12 months they begin to perceive how this space may be extended by a mechanical aid. 相似文献
8.
The focus of this study was on the ability of infants to perceive whether an object is positioned at a distance that would make contact possible. As a toy was presented, sometimes within and sometimes beyond reach, the initiation of reaching and leaning forward was scored. Infants were divided into leaning and nonleaning groups. Both leaning and nonleaning 5-month-olds changed their behavior dramatically when the object was placed beyond, as opposed to within, reach. The nonleaners showed a decline in reaching when this boundary for contact was crossed. The "leaners" did not; rather, they began to lean forward. These results suggest that 5-month-olds use information for the affordance of contact. 4-month-olds provided less evidence that arm length regulates reaching. 5-month-old infants acted as if they not only had some sensitivity to the absolute distance of an object but also to the effect that leaning forward has on their ability to make contact with a distant object. 相似文献
9.
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
10.
Common Themes and Cultural Variations in Japanese and American Mothers' Speech to Infants 总被引：1，自引：0，他引：1
This study explored both universal features and cultural variation in maternal speech. Japanese and American mothers' speech to infants at 6, 12, and 19 months was compared in a cross-sectional study of 60 dyads observed playing with toys at home. Mothers' speech in both cultures shared common characteristics, such as linguistic simplification and frequent repetition, and mothers made similar adjustments in their speech to infants of different ages. American mothers labeled objects more frequently and consistently than did Japanese mothers, while Japanese mothers used objects to engage infants in social routines more often than did American mothers. American infants had larger noun vocabularies than did Japanese infants, according to maternal report. The greater emphasis on object nouns in American mothers' speech is only partially attributable to structural differences between Japanese and English. Cultural differences in interactional style and beliefs about child rearing strongly influence the structure and content of speech to infants. 相似文献
11.
提出了三指机器人手抓取规划的一种研究方法．通过对人手抓取操作动作的分析,归纳出三指抓取的两种典型方式．综合任务要求、物体的几何和物理特性以及环境信息,获得了三指手的抓取姿态和可抓取平面．最后将抓取规划过程归结为可行抓取平面上三个抓取位置的确定． 相似文献
12.
In this study, 6‐month‐olds' ability to mentally rotate objects was investigated using the violation‐of‐expectation paradigm. Forty infants watched an asymmetric object being moved straight down behind an occluder. When the occluder was lowered, it revealed the original object (possible) or its mirror image (impossible) in one of five orientations. Whereas half of the infants were allowed to manually explore the object prior to testing, the other half was only allowed to observe the object. Results showed that infants with prior hands‐on experience looked significantly longer at the mirror image, while infants with observational experience did not discriminate between test events. These findings demonstrate that 6‐month‐olds' mental rotations benefit from manual exploration, highlighting the importance of motor experience for cognitive performance. 相似文献
13.
The effects of 3 weeks of social (control), postural, or object‐oriented experiences on 9‐ to 21‐week‐old infants’ (N = 42) reaching, exploration, and means–end behaviors were assessed. Coders recorded object contacts, mouthing, fingering, attention, and affect from video. Postural and object‐oriented experiences advanced reaching, haptic exploration of objects, and developing means–end behavior compared to social experience. Object‐oriented experience best‐advanced means–end behavior. The results suggest that the development of novel behaviors is dependent on multiple subsystems and can be similarly advanced by addressing a variety of these subsystems. They also suggest that past experiences with active object exploration can facilitate early information processing and the development of early knowledge. 相似文献
14.
The motivational characteristics of a small sample of normally developing deaf and hearing 12-month-old infants were assessed using procedures derived from Yarrow's work. The data supported the following conclusions: 1. Both deaf and hearing infants exhibit similar amounts of motivated behavior toward objects which suggests that auditory contact with their surroundings is not a determining factor in infants' attempts to master objects. 2. The deaf infants spent a longer period of time engaged in social behaviors than did the hearing infants and without any apparent sacrifice to the deployment of their task- and goal-directed activities. This finding implies that the deaf infants were more skillful at integrating the competing demands of social- and object-oriented endeavors than were their hearing peers. 3. The deaf infant engaged with the social environment and displayed a positive emotional response to the situation sooner than the hearing infants. Positive affect also was more likely to be followed by a social behavior for the deaf infants which indicates that the integration of social- and object-oriented activities serves either a different or more potent function in the early development of deaf infants. We believe that these data offer some preliminary, empirically based support for a developmental difference model when intervention strategies for deaf infants are contemplated. The policy implications for such a move may include a reduction in cognitively oriented activities and an increase in activities designed to capitalize on deaf infants' social and visual compensatory skills. 相似文献
15.
《Early education and development》2013,24(1):19-34
The motivational characteristics of a small sample of normally developing deaf and hearing 12-month-old infants were assessed using procedures derived from Yarrow's work. The data supported the following conclusions: 1. Both deaf and hearing infants exhibit similar amounts of motivated behavior toward objects which suggests that auditory contact with their surroundings is not a determining factor in infants' attempts to master objects. 2. The deaf infants spent a longer period of time engaged in social behaviors than did the hearing infants and without any apparent sacrifice to the deployment of their task- and goal-directed activities. This finding implies that the deaf infants were more skillful at integrating the competing demands of social- and object-oriented endeavors than were their hearing peers. 3. The deaf infant engaged with the social environment and displayed a positive emotional response to the situation sooner than the hearing infants. Positive affect also was more likely to be followed by a social behavior for the deaf infants which indicates that the integration of social- and object-oriented activities serves either a different or more potent function in the early development of deaf infants. We believe that these data offer some preliminary, empirically based support for a developmental difference model when intervention strategies for deaf infants are contemplated. The policy implications for such a move may include a reduction in cognitively oriented activities and an increase in activities designed to capitalize on deaf infants' social and visual compensatory skills. 相似文献
16.
Recent evidence suggests adults and infants selectively attend to features of action, such as how a hand contacts an object. The current research investigated whether this bias stems from infants' processing of the functional consequences of grasps: understanding that different grasps afford different future actions. A habituation paradigm assessed 10-month-old infants' (N = 62) understanding of the functional consequences of precision and whole-hand grasps in others' actions, and infants' own precision grasping abilities were also assessed. The results indicate infants understood the functional consequences of another's grasp only if they could perform precision grasps themselves. These results highlight a previously unknown aspect of early action understanding, and deepen our understanding of the relation between motor experience and cognition. 相似文献
17.
Daniel H. Ashmead Michael E. McCarty Linda S. Lucas Mariana C. Belvedere 《Child development》1993,64(4):1111-1127
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.
A study of multimodal motherese: the role of temporal synchrony between verbal labels and gestures 总被引：1，自引：0，他引：1
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
19.
The present article shows that infant and dyad differences in hand–eye coordination predict dyad differences in joint attention (JA). In the study reported here, 51 toddlers ranging in age from 11 to 24 months and their parents wore head‐mounted eye trackers as they played with objects together. We found that physically active toddlers aligned their looking behavior with their parent and achieved a substantial proportion of time spent jointly attending to the same object. However, JA did not arise through gaze following but rather through the coordination of gaze with manual actions on objects as both infants and parents attended to their partner's object manipulations. Moreover, dyad differences in JA were associated with dyad differences in hand following. 相似文献
20.
Infants' ability to mentally track the orientation of an object during a hidden rotation was investigated (N = 28 in each experiment). A toy on a turntable was fully covered and then rotated 90°. When revealed, the toy had turned with the turntable (probable event), remained at its starting orientation (improbable event in Experiment 1), or turned to the opposite side (improbable event in Experiment 2). Results demonstrated a developmental progression between 14 and 16 months of age in infants' sensitivity to spatial object relations and their ability to track the orientation of an object during hidden rotation. Experiment 3 showed that 14‐month‐olds' performance improved with hands‐on training, highlighting the role of action experience in cognitive development. 相似文献