Developmental changes in the understanding of temporal sequence

In 3 experiments, 4-, 5-, and 6-year-olds' ability to sequence events was examined. We hypothesized that children initially construct temporal sequences by relying on the organization of their world knowledge instead of inferring logical relations among actions. In the first experiment, children generated picture sequences of familiar and unfamiliar events in forward and backward order without having seen the pictures in their correct sequence. In the second experiment, children reconstructed previously seen sequences, and in the third experiment, children were shown forward and backward sequences and reconstructed them in the opposite direction. Across experiments, the same pattern of performance was found; familiar events in forward order were the easiest to sequence, then unfamiliar events in forward order, familiar events in backward order, and finally unfamiliar events in backward order. These results are discussed along with other findings suggesting a similar pattern of performance across a wide developmental age span.     

Developmental changes in hemispheric independence

In this research, we questioned whether children's relative inability to use the 2 cerebral hemispheres independently contributes toward their difficulty with the simultaneous execution of conflicting tasks. 2 naming tasks were simultaneously presented to either 1 visual field/hemisphere combination (unilateral) or were divided between visual fields/hemispheres (bilateral). We predicted that bilateral presentation would improve performance by insulating these conflicting tasks from mutual interference and that there would be a developmental shift in the size of the advantage for bilateral presentation. This hypothesis was confirmed in a sample of 120 children (N = 40 per group). Older children (12- and 14-year-olds) named more items when they were presented bilaterally, rather than unilaterally, when conflicting inputs were directed to different hemispheres. Younger children (10-year-olds) displayed no advantage for bilateral presentation regardless of whether conflicting tasks were projected to the same hemisphere or different hemispheres. The fact that 10-year-olds did not benefit from division of conflicting inputs between the hemispheres was interpreted as a symptom of their relative inability to use the hemispheres independently.     

Developmental changes in ideas about lying

Videotaped stories depicting deliberate lies and unintentionally untrue statements were presented to 200 subjects evenly divided into the following age groups: 5, 8, 9, and 11 years and adult. Definitions of lying were seen to change gradually over this age range. Adults were more lenient than children in their moral evaluations of all the statements. All age groups rated a guess that did no harm as better than one that caused trouble, and they all judged selfishly motivated lies to be worse than both unintended falsehoods and "jocose" lies that aimed to please the listener. 11-year-olds tended to justify the prohibition against lying in terms of trust and fairness, whereas younger children cited authority's punitive sanctions.     

Developmental changes in auditory temporal perception

Infants, preschoolers, and adults were tested to determine the shortest time interval at which they would respond to the precedence effect--an auditory phenomenon produced by presenting the same sound through 2 loudspeakers with the input to 1 loudspeaker delayed relative to the other. The delayed sound is not localized at its source until time delays between onsets are lengthened beyond a critical limit, or threshold. Thresholds for the precedence effect were defined as the delay interval below which listeners respond only to the leading loudspeaker and above which they respond to both loudspeakers. Threshold estimates were determined for adults and preschoolers with an ascending and descending series, followed by a method of constant stimuli series. Infants were trained to respond to the delayed sound using a visually reinforced headturning procedure. For clicks, preschoolers' and adults' thresholds were around 12 msec, while 6-month-olds stopped responding to the delayed sound around 25 msec. A similar developmental difference in threshold was expressed between preschoolers and adults for a more complex sound, with younger subjects hearing the precedence effect over a longer time delay.     

Developmental changes in children's choices of practice strategies

This study investigated children's choices of deliberate practice strategies. Six-to 11-year-olds (n = 85) were presented with three outwardly similar motor tasks that varied only in the precision of the motor response required to succeed. Children then had the opportunity to practice these tasks before a “test” in which they had to complete all three tasks in the fastest overall time. While children of all ages spent relatively more time practicing the hardest task, only 10- and 11-year-olds scored more successes on the hardest task than the other tasks during the initial practice period. After verbal instruction, however, children of all ages scored more successes on the hardest task during practice, and younger children became more likely to persevere with the hardest task rather than switching tasks after a success. Children's practice choices may vary as a function of age and verbal instruction.     

Developmental changes in the coherence of essentialist beliefs about psychological characteristics

Essentialism is the belief that certain characteristics (of individuals or categories) may be relatively stable, unchanging, likely to be present at birth, and biologically based. The current studies examined how different essentialist beliefs interrelate. For example, does thinking that a property is innate imply that the property cannot be changed? Four studies were conducted, examining how children (N=195, grades 1-7; ages 7-13) and adults (N=187) reason about familiar and novel social characteristics. By 3rd grade (9 years), children showed some coherence of essentialist beliefs. In contrast, younger children expected less interrelatedness among dimensions than older children or adults. These findings suggest that essentialist attributions at first consist of separate strands that children eventually link together into a more coherent understanding.     

Developmental changes in the scanning of faces by young infants.

6 1-month-old infants and 6 2-month-old infants each viewed 3 faces (his mother's, a strange woman's, and a strange man's) while his eye movements were recorded by corneal photography. The 1-month-olds fixated away from the faces most of the time, and they looked at their mothers even less often than at the strangers. When they did fixate a face, they usually chose a limited portion of the perimeter. By constrast, 2-month-olds fixated the faces most of the time, looked at more features, and were more likely to look at internal features, especially the eyes. This scanning resembles that reported previously for 2-dimensional shapes, although in some respects it appears unique to faces.     

Developmental changes in the understanding of implied motion in two-dimensional pictures.

The power of various pictorial movement cues in eliciting a reading of movement was studied to determine the relationship between the ease with which a picture is interpreted and the degree to which the picture retains the structure of reality. Movement was indicated in 2 ways: pictorial conventions indicated movement by lines, blurs, and vibration marks; and pictorial postures indicated movement by figures which were isomorphic with the postures involved in real movement. Preschoolers, first graders, sixth graders, and college students were asked to label and sort pictures of human figures as "moving" or "still". Members of the 2 young groups did not classify pictures with conventional cues as "moving" as often as they did pictures with postural cues. Members of the 2 older groups classified both types of pictures as "moving". Since postural cues for movement are recognized at an earlier age than conventional cues, those that are more similar to reality may be easier to understand.     

Developmental changes in the allocation of semantic feedback during visual word recognition

The present study used a mediated priming paradigm to examine whether developmental differences exist in the integration of semantic information with orthographic and phonological information during visual word recognition. In Experiment 1, we found that the integration of semantics with phonology and orthography differed among third‐grade, sixth‐grade and college students: orthographically based mediated inhibition effects were found in third‐grade children, whereas phonologically based mediated inhibition effects were found in sixth‐grade children and college students. A second experiment was performed with adults to test the hypothesis that the orthographically based mediated inhibition effect observed with young children was due to deficits in orthographic processing. When stimulus quality was manipulated within the mediated priming paradigm, orthographically based mediated inhibition effects were found when targets were dim, whereas phonologically based mediated inhibition effects were found when targets were bright. Taken together, these results suggest that the allocation of activation during reading may depend on the processing demands of the word recognition system.     

Choice of operation in verbal problems with decimal numbers

This article examines the conceptual problems that children experience when attempting to solve verbal problems which contain decimal numbers. After discussing the existing research, we then describe an experiment that was designed in three phases:

1. Exploratory interviews to discover existing conceptions and difficulties and to discover how pupils made use of diagrams, simpler numbers, and strategies. These interviews exposed difficulties with the understanding of place value, the effect of multiplying and dividing by a positive number less than one, the symbolisms of division and its noncommutative nature, the units associated with the numbers and also with familiar names for the operations. The three strategies were all found to be unfamiliar to pupils and their difficulties are discussed.
2. The design and administration of a diagnostic test, based on the results of these interviews, to a class of less able 14 year olds.
3. The preparation and use of calculator enriched teaching materials designed to remedy the identified misconceptions. From the pre- and post-test results we note the dramatic success of the teaching in improving pupils' understanding of place value, although there is a more modest improvement in enabling pupils to choose the correct operation by drawing diagrams, using easier numbers and estimating.

     

异步十进制可逆计数器的设计

通过对异步十进制加法、减法计数器的分析 ,进一步设计出既能完成加法计数又能完成减法计数的逻辑电路即可逆计数器 ,并对它进行实验验证     

Developmental changes and socioeconomic differences in mother-infant picturebook reading

Picturebook reading is a common form of interaction between parents and young children. This study examined developmental changes and socioeconomic differences in picturebook interactions of motherinfant Argentine dyads. 21 middle and 18 low SES mothers with their 12 to 24 months-old infants interacting with two different books, were observed. It was found that mothers of both SES groups adjusted the level of their demands not only to the task requirements (books) but also to the age of the infant. However, it was also found that the style of the interaction was different depending on the SES of the mother-infant pair. A more demanding and elaborated maternal language along with a linguistically more competent child were found in the middle SES group.     

Developmental changes in uncertainty monitoring during an event recall task

The present study was conducted to examine developmental progression in children’s metacognitive monitoring competencies in the context of a complex memory task. 7- and 9-year-olds rated their confidence after answering questions in two different question formats (unbiased and misleading) and two different question types (answerable and unanswerable). Feeling-of-knowing judgments were gathered for questions that had previously been answered with “don’t know.” The results showed that children from both age groups appropriately differentiated between correct and incorrect answers to unbiased questions in their confidence judgments, between answerable and unanswerable questions, and appropriately showed lower confidence levels in their confidence judgments than in their feeling-of-knowing judgments. 9-year-olds proved to be further able to discriminate metacognitively between correct and incorrect answers to misleading answerable questions in their confidence judgments while 7-year-olds were not. The comparison of feeling-of-knowing judgments before correct and incorrect recognition indicated that metacognitive differentiation at the lower end of the uncertainty–certainty continuum posed problems for these age groups. The observation of an adult confederate modeling appropriate metamemory monitoring did not improve children’s metacognitive performance.

异步十进制加法计数器的实验改进

从实验出发，对现行教材中的异步十进制计数器所出现的问题加以改进，使理论与实践相吻合，同时讨论了并非在任何情况下均可用线与。     

Developmental changes and individual differences in young children's moral judgments

Developmental trajectories and individual differences in 70 American middle‐income 2½‐ to 4‐year olds’ moral judgments were examined 3 times across 1 year using latent growth modeling. At Wave 1, children distinguished hypothetical moral from conventional transgressions on all criteria, but only older preschoolers did so when rating deserved punishment. Children’s understanding of moral transgressions as wrong independent of authority grew over time. Greater surgency and effortful control were both associated with a better understanding of moral generalizability. Children higher in effortful control also grew more slowly in understanding that moral rules are not alterable and that moral transgressions are wrong independent of rules. Girls demonstrated sharper increases across time than boys in understanding the nonalterability of moral rules.     

Developmental changes in children's awareness of strategies for coping with uncontrollable stress

Children at 3 age levels (5-6 1/2, 7 1/2-9, and 10-12 years) were interviewed to determine their spontaneous suggestions of coping strategies designed to manage frustration caused by waiting for a desired object (positive valence) and fear caused by waiting for an unpleasant event (negative valence) in uncontrollable situations. Subjects' responses were grouped into categories based on coping techniques discussed in the adult coping literature on a continuum from approach to avoidance techniques. The avoidance tactics, the main focus of interest, were further divided into 4 distinct forms. In contrast to investigations of children's coping in more controllable situations, approach strategies were very infrequently mentioned. An age increase was found in the proportion of cognitive distraction strategies suggested, but behavioral distraction strategies were most frequently suggested by children at all age levels and did not differ significantly across age. The developmental differences were particularly evident for the negative valence scenarios and, within the negative valence scenarios, for the story likely to be the most stressful to young children--getting a shot. The results are discussed in terms of possible reasons for age differences in cognitive but not behavioral distraction and their implications for children's ability to cope with uncontrollable stress.