共查询到20条相似文献，搜索用时 46 毫秒
1.
46 3-month-old infants were presented with geometric stimuli moving laterally at two different velocities (34.8 degrees/sec; 103.3 degrees/sec). The results were interpreted as evidence that 3-month-old infants could discriminate between geometric forms moving at velocities that, according to previous findings, might interfere with shape discrimination. The findings are discussed in relation to the possible interactive effect of type and velocity of movement on geometric form discrimination. 相似文献
2.
Newborn infants orient to sounds. 总被引：1，自引：0，他引：1
In 2 experiments, the majority of 21 newborn infants who were maintained in an alert state consistently turned their heads toward a continuous sound source presented 90 degrees from midline. For most infants this orientation response was rather slow, taking median latencies of 2.5 sec to begin and 5.5 sec to end. The most important factors in producing this impressive response seem to be the method of holding the infants during testing and the nature of the auditory stimulus. 相似文献
3.
This study examines the relationships between neonatal sleep respiratory instability and infant development. A group of 122 full-term healthy infants was observed during a nap within the first and fourth weeks of life. During each nap, a continuous polygraphic recording was obtained of respiratory activity and extraocular movements. The relative frequency and average duration of apneic pauses (greater than or equal to 2 sec) in each testing session for an infant were employed to calculate a measure of respiratory instability (PSA4) previously found to be related to the occurrence of prolonged sleep apnea. 28 of the infants in this study were maintained at home on apnea monitors. The Bayley Scales of Infant Development were administered to each infant at approximately 9 months of age. Comparisons of infants with high versus low PSA4 values and of monitored versus unmonitored infants were not strongly distorted by imbalances in birth weight, sex, race, birth order, method of feeding, Sudden Infant Death Syndrome (SIDS) sibship, parental education, age at developmental assessment, and developmental tester. Those with increased respiratory instability (PSA4 greater than or equal to -0.04) within the first week of life averaged significantly lower in mental and psychomotor development. Utilization of home apnea monitors was not significantly associated with developmental scores. 相似文献
4.
S A Rose 《Child development》1988,59(5):1161-1176
To investigate the integration of visual information across space and time, infants watched the contour of a shape being traced out by a moving point source of light and then viewed 2 objects: 1 with the shape they had just seen traced and 1 with a novel shape. In the first study, which varied the number of tracings (velocity about 16.7 cm/sec), 12-month-olds looked longer at the novel object in all conditions, indicating that they recognized the similarity between the alternative object and tracing of like contour. Study 2, which varied velocity (14.7 and 7.4 cm/sec), stimuli, and the number of tracings, provided evidence for the generalizability of these results but indicated that performance suffered at the slower speed. Studies 3 and 4 held velocity constant (14.7 cm/sec) while varying the size of the tracings and age of the infant: 12-month-olds, but not 6-month-olds, recognized figures in instances where it took up to 10 sec to complete a single tracing. Because it took so long to complete many of the tracings, central rather than purely retinal mechanisms appear to be involved in integrating shape in these situations. 相似文献
5.
Development of the ability to use recall to guide action, as indicated by infants' performance on AB 总被引：2，自引：0，他引：2
A Diamond 《Child development》1985,56(4):868-883
25 infants were tested every 2 weeks on the AB Object Permanence Task devised by Piaget, from the age when they first reached for a hidden object until they were 12 months. The delay between hiding and retrieval necessary to produce the AB error increased continuously throughout this period at an average rate of 2 sec/month, from under 2 sec at 7 1/2 months to over 10 sec by 12 months. All children displayed the AB error repeatedly over the months of testing. Large between-children differences in delay needed for the AB error were found at each age. Girls tolerated longer delays than boys. The characteristic pattern to the AB error did not vary over age or sex. Range of delay producing the AB error in any child was small. Errors disappeared when delays were reduced by 2-3 sec, and reaching became random or severely perseverative when delays were increased 2-3 sec above the level producing AB error. AB provides an index of the ability to carry out an intention based on stored information despite a conflicting habitual tendency. 相似文献
6.
Diana S.Y. Tham Alison Rees J. Gavin Bremner Alan Slater Scott P. Johnson 《Child development》2021,92(1):324-334
Infants' oculomotor tracking develops rapidly but is poorer when there are horizontal and vertical movement components. Additionally, persistence of objects moving through occlusion emerges at 4 months but initially is absent for objects moving obliquely. In two experiments, we recorded eye movements of thirty-two 4-month-old and thirty-two 6-month-old infants (mainly Caucasian-White) tracking horizontal, vertical, and oblique trajectories. Infants tracked oblique trajectories less accurately, but 6-month olds tracked more accurately such that they tracked oblique trajectories as accurately as 4-month olds tracked horizontal and vertical trajectories. Similar results emerged when the object was temporarily occluded. Thus, 4-month olds’ tracking of oblique trajectories may be insufficient to support object persistence, whereas 6-month olds may track sufficiently accurately to perceive object persistence for all trajectory orientations. 相似文献
7.
Dampening of Adrenocortical Responses during Infancy: Normative Changes and Individual Differences 总被引：6，自引：0，他引：6
Changes in cortisol and behavioral responses were examined longitudinally in 83 infants (39 girls, 44 boys) tested at their well-baby exams with inoculations at 2, 4, 6, and 15 months (72 infants completed all testing). Another sample of 2-, 4-, and 6-month-olds ( n = 18 per age) received mock exams without inoculations to determine early developmental changes to the exam procedures. Behavioral distress was coded every 30 sec during the exam, a 5-min inoculation period, and a 20-min recovery period. Salivary cortisol was obtained upon arrival at the clinic and 25 min after the beginning of the inoculation period. To the exam-inoculation procedures, cortisol responses were high at 2 months, decreased significantly between 2 and 4 months, remained comparable between 4 and 6 months, and then declined again between 6 and 15 months. Between 6 and 15 months there was also a decrease in pretest cortisol. By 15 months, significant increases in cortisol from pre- to posttest were no longer observed for most infants. To the exam-only procedures, cortisol responses decreased between 2 and 4 months, and by 4 months most infants failed to show pre- to posttest increases in cortisol. Behavioral distress decreased between 2 and 6 months, but increased again at 15 months. While crying and cortisol were modestly correlated during the 2- to 6-month exam-inoculation procedures, at 15 months no significant correlations were obtained. Behavioral and hormonal reactions thus followed different ontogenetic paths and may provide different information about infant functioning. There was some evidence that the emergence of the circadian rhythm in cortisol might be related to the early decrease in cortisol response. 相似文献
8.
The experiments reported in the present study tested whether decreasing intertrial intervals (ITIs) intensifies the disruptive
effects of increasing retention intervals (RIs) in a delayed conditional discrimination by decreasing the animal’s trial tracking
accuracy (Cohen & Armstrong, 1996; Cohen & Roberts, 1996). Rats responded on a fixed ratio (FR) 1 or fixed interval (FI) 10-sec
reinforcement schedule at a second light or tone stimulus, S2, when the first light or tone stimulus, S1, had signaled an
FI 10-sec or FR 1 schedule, respectively. RIs between S1 and S2 were increased from 3 to 24 sec and never exceeded ITIs that
were reduced from 24 to 6 sec. For some rats, the trials were separated from each other by extending the lever at S1 and retracting
it at the end of S2 (ITI lever-retracted group). For other, control rats, the lever remained extended throughout the session
(lever-extended group, Experiment 1) or was extended and retracted with the onset and offset of each stimulus (RI/ITI lever-retracted
group, Experiment 2). The rats under all trial conditions learned to delay leverpressing on the FI 10-sec schedule. Latency
to begin leverpressing on the FI 10-sec schedule declined as RIs were increased, but this effect was attenuated in the ITI
lever-retracted groups in both experiments, as would be predicted by thetrial tracking hypothesis. Decreasing ITIs from 24 to 6 sec intensified the disruptive effects of increasing RIs from 3 to 6 sec in the
RI/ITI lever-retracted group (Experiment 2), as would be predicted by the trial tracking hypothesis. 相似文献
9.
Adults process speech incrementally, rapidly identifying spoken words on the basis of initial phonetic information sufficient to distinguish them from alternatives. In this study, infants in the second year also made use of word-initial information to understand fluent speech. The time course of comprehension was examined by tracking infants' eye movements as they looked at pictures in response to familiar spoken words, presented both as whole words in intact form and as partial words in which only the first 300 ms of the word was heard. In Experiment 1, 21-month-old infants (N = 32) recognized partial words as quickly and reliably as they recognized whole words; in Experiment 2, these findings were replicated with 18-month-old infants (N = 32). Combining the data from both experiments, efficiency in spoken word recognition was examined in relation to level of lexical development. Infants with more than 100 words in their productive vocabulary were more accurate in identifying familiar words than were infants with less than 60 words. Grouped by response speed, infants with faster mean reaction times were more accurate in word recognition and also had larger productive vocabularies than infants with slower response latencies. These results show that infants in the second year are capable of incremental speech processing even before entering the vocabulary spurt, and that lexical growth is associated with increased speed and efficiency in understanding spoken language. 相似文献
10.
The current study examines the developmental trajectory of banging movements and its implications for tool use development. Twenty (6‐ to 15‐month‐old) infants wore reflective markers while banging a handled cube; movements were recorded at 240 Hz. Results indicated that through the second half‐year, banging movements undergo developmental changes making them ideally suited for instrumental hammering and pounding. Younger infants were inefficient and variable when banging the object: Their hands followed circuitous paths of great lengths at high velocities. By 1 year, infants showed consistent and efficient straight up‐down hand trajectories of smaller magnitude and velocity, allowing for precise aiming and delivering dependable levels of force. The findings suggest that tool use develops gradually from infants' existing manual behaviors. 相似文献
11.
Ontogeny of infantile oral reflexes and emerging chewing 总被引：1，自引：0，他引：1
The ontogeny of rooting, lip, lateral tongue, mouth opening, biting, and Babkin reflexes and emerging chewing behaviors were observed in 2 normal infants from 1 week to 35 weeks of age. These behaviors were videotaped at 9 monthly test sessions, and their movement patterns analyzed during slow-motion playback. The reflex responses were elicited in both infants through 35 weeks of age. They consisted of those characteristic movements described in the literature plus additional movements that elaborated the characteristic pattern. The complexity of the reflexes and the quality of movement changed with age. Components of chewing, which emerged sequentially from 1 week of age, were cyclical mandibular elevation and depression, lateral tongue movements, transport of the bolus from lateral to medial oral position, mandible retrusion, lateralization and protrusion movements in association with mandibular elevation and depression, increase in speed of rhythmical chewing movements to the mature speed of 1 cycle per second, and mastication. Chewing and oral reflexes contained similar movements but differed in the relative frequency of certain characteristic movements and in the stimulus response relationship. 相似文献
12.
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
13.
The present study examined the use of statistical cues for word boundaries during Chinese reading. Participants were instructed
to read sentences for comprehension with their eye movements being recorded. A two-character target word was embedded in each
sentence. The contrast between the probabilities of the ending character (C2) of the target word (C12) being used as word
beginning and ending in all words containing it was manipulated. In addition, by using the boundary paradigm, parafoveal overlapping
ambiguity in the string C123 was manipulated with three types of preview of the character C3, which was a single-character
word in the identical condition. During preview, the combination of C23′ was a legal word in the ambiguous condition and was
not a word in the control condition. Significant probability and preview effects were observed. In the low-probability condition,
inconsistency in the frequent within-word position (word beginning) and the present position (word ending) lengthened gaze
durations and increased refixation rate on the target word. Although benefits from the identical previews were apparent, effects
of overlapping ambiguity were negligible. The results suggest that the probability of within-word positions had an influence
during character-to-word assignment, which was mainly verified during foveal processing. Thus, the overlapping ambiguity between
parafoveal words did not interfere with reading. Further investigation is necessary to examine whether current computational
models of eye movement control should incorporate statistical cues for word boundaries together with other linguistic factors
in their word processing system to account for Chinese reading. 相似文献
14.
C. C. Krischer R. Coenen M. Heckner D. Hoeppner R. Meissen 《Educational research; a review for teachers and all concerned with progress in education》2013,55(3):271-283
In support of efforts at reducing the number of dyslexics and illiterates in industrialized countries it is proposed, for the first time, to use gliding text ‐ as known in television subtitles ‐ as a method of text display to help those learning to read. Beginners, having the difficult task of precisely directing their gaze letter by letter along the line of text, experience with gliding text automatic gaze guidance as in so‐called ‘optokinetic nystagmus’. This subconscious gaze control allows beginners to pay more attention to contextual processing. First training courses have shown that exercises with gliding text are very efficient. Reading difficulties were eliminated for 21 second‐grade elementary school children in only 24 training sessions, each of 15 min duration. The mean reading speed increased from ten to 24 words per minute (WPM). 相似文献
15.
10 abused toddlers (ages 1-3 years) and 10 matched controls from families experiencing stress were observed during social interactions with caregivers and with peers in their daycare settings. The abused infants more frequently physically assaulted their peers. They "harassed" their caregivers verbally and nonverbally, and they were the only infants who assaulted or threatened to assault them. The abused infants were much less likely than the controls to approach their caregivers in response to friendly overtures; when they did so they were more likely to approach to the side, to the rear, or by turning about and backstepping. In response to friendly overtures the abused infants more frequently avoided peers and caregivers or combined movements of approach with movements of avoidance. A similar behavior pattern has been identified by Main in maternally rejected infants in normal samples. 相似文献
16.
Esther Thelen Daniela Corbetta Kathi Kamm John P. Spencer Klaus Schneider Ronald F. Zernicke 《Child development》1993,64(4):1058-1098
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
17.
Infants with Down syndrome (DS) represent a population in which new behaviors are acquired significantly more slowly than in nondisabled infants. We propose that infants' spontaneous movements hold a key to understanding the process of development—of integrating intrinsic dynamics and function. In this investigation, we compared the spontaneous leg movements of 10 infants with DS and 2 groups of nondisabled (ND) infants matched for chronological age and motor age. In contrast to common perceptions, we did not observe a significant difference in the frequency of movements between infants with DS and ND infants. But, infants with DS demonstrated significantly fewer of the most complex patterned leg movements, that is, kicking patterns. Further, the frequency with which both DS and ND infants kicked was significantly correlated with the age at which they began to walk. Biomechanical variables were identified, as well, that related to their emergent movement patterns. These data are consistent with Edelman's proposal that spontaneous movements that occur repeatedly in regions of the organism's functional work space facilitate the development of stable behavioral patterns and emphasize the role of the interaction of multiple subsystems in the emergence of new behaviors. 相似文献
18.
In three experiments with rat subjects, we examined the effects of trial spacing in appetitive conditioning. Previous research
in this preparation suggests that self-generated priming of the conditional stimulus (CS) and/or unconditional stimulus (US)
in short-term memory is a cause of the trial-spacing effect that occurs with intertrial intervals (ITIs) of less than 240
sec. Experiment 1 nonetheless showed that a trial-spacing effect still occurs when ITIs are increased beyond 240 sec, and
that the effect of ITI over 60–1,920 sec on conditioned responding is best described as a linear function. In Experiment 2,
some subjects were removed from the context during the ITIs, preventing extinction of the context. Removal abolished the advantage
of the long ITI, suggesting the importance of exposure to the context during the long ITI. Experiment 3 still produced a trial-spacing
effect in a within-subjects design that controlled for the level of context conditioning and reinforcement rate in the absence
of the CS. Overall, the results are most consistent with the idea that adding time to the ITI above 240 sec facilitates conditioning
by extinguishing context-CS associations—and possibly context-US associations—that otherwise interfere with CS-US learning
through retrieval-generated priming (see, e.g., Wagner, 1981). 相似文献
19.
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
20.
Jennifer J. Higa 《Learning & behavior》1997,25(2):177-184
The present experiment examined temporal control of wait-time responses by interfood interval (IFI) duration. We exposed rats to a sequence of intervals that changed in duration at an unpredictable point within a session. In Phase 1, intervals changed from 15 to 5 sec (step-down) or from 15 to 45 sec (step-up). In Phase 2, we increased the intervals by a factor of four. We observed rapid timing effects during a transition in both phases of the experiment: A step-down and a step-up transition significantly decreased and increased wait time in thenext interval, respectively. Furthermore, adjustment of wait times during step-down was largely complete by the third transition IFI. In contrast, wait times gradually increased across several transition IFIs during step-up. The results reveal dynamic properties of temporal control that depend on the direction in which IFIs change. 相似文献