Effects of contextual interference and age on acquisition, retention, and transfer of motor skill.

This experiment was designed to investigate the varying conditions of contextual interference within three age groups. 40 5-yr.-olds, 40 7-yr.-olds, and 40 11-yr.-olds practiced the task of throwing beanbags under either low contextual interference (blocked practice), high contextual interference (random practice), or medium contextual interference (combined practice). All subjects performed 30 acquisition trials, 12 retention trials and 6 transfer trials. Analysis indicated that only the 7-yr.-old subjects differed in their performance in the various practice groups. As hypothesized and suggested by developmental theories, the combined and blocked practice groups acquired the task better. On the other hand, the 5- and 11-yr.-olds did not differ in performance in the different practice groups. Whether this is associated with difficulty of the task or the length of practice can be assessed in further study. Contextual interference in different age groups needs further investigation.     

Environmental influences on perceptual and motor skills of children from immigrant Ethiopian families

The purpose of this study was to examine environmental influences on perceptual and motor skills of children from immigrant Ethiopian families in Israel in comparison with those of Israeli-born children. The subjects were divided into groups based on age (6- to 8-yr.-olds and 10- to 12-yr.-olds) and length of time in Israel. The results of this study show that the perceptual and motor performance of 6- to 8-yr.-old, less recent Ethiopian immigrants is similar to that of the recent Ethiopian immigrants of the same age. A difference exists between those two groups and the Israeli-born children of the same age. In the 10- to 12-yr.-old age group, there is a marked difference between the performance of the two groups of Ethiopian immigrants. The difference between the less recent immigrants and the Israeli-born children is smaller for most tasks; however, the less recent immigrants' performance is still poorer than that of the Israeli children. These results are compatible with those of other studies describing the difficulties encountered by children who had not studied in formal educational settings and those who have had that experience.     

Age-related trends of interference control in school-age children and young adults in the Stroop color-word test

In this cross-sectional study, differences in interference control, one component of executive function, were investigated among three age groups, 15 early childhood (7- to 8-yr.-olds), 25 middle childhood (9- to 12-yr.-olds), and 20 young adults (21- to 30-yr.-olds). Participants were administered a computer version of the Stroop color-word test with an oral response; correct responses, response time (RT), and the interference ratio were examined. The data indicated that (1) most of the participants showed no errors in word reading, color-naming, and incongruent color-naming tasks; (2) in word-reading and color-naming tasks, RT for 7- to 8-yr.-olds was longer than that for 9- to 12-yr.-olds, while RT of 9- to 12-yr.-olds and young adults were comparable; (3) in an incongruent color-naming task, RT for 7- to 8-yr.-olds was longer than RT for 9- to 12-yr.-olds, which was longer than RT for young adults; and (4) the interference ratio was higher in 7- to 8-yr.-olds than in 9- to 12-yr.-olds, which was higher than in young adults. These results suggested the difference in interference control between early and middle childhood reported on the go/no-go task and the stop-signal procedure would be observed in the Stroop color-word paradigm as well. The utility of this modified Stroop color-word test for those with intellectual and developmental disabilities was discussed.     

Injuries due to school sports accidents in 4 to 13-yr.-old children

505 kindergarten and primary school children from 4 to 13 years of age were treated for school sports injuries during the period 1990-1997. The incidence of injuries increased statistically significantly from .5 per 1,000 children 4- to 5-yr.-old to 4.8 injured children per 1,000 in 12- to 13-yr.-old. 59% of the injuries involved upper extremities; 35% of these were in the wrist region. 33.5% of the injuries were of the lower extremities, with 50% being of the feet and 36.4% of the ankle. Accidental falls were the main situation (53%) in which school sport accidents occurred. Nearly 65% of these accidental falls occurred at the ground level; the remaining accidents (35%) occurred when the child was working on an apparatus, e.g., parallel bars, balancing beam, side horse. The 4- to 5-yr.-old children were the most vulnerable to accidental fall (67%). A statistically significant increase in injuries in ball sports was observed from 4- to 5-yr.-olds (0%) to the 12- to 13-yr.-olds (28%).     

Developmental changes in response preparation to visual stimuli

We examined how preparation to respond changes with age. Subjects from four age groups (5- to 7-, 8- to 11-, 12- to 17-, and 18- to 24-yr.-olds) were given a simple visual RT task with foreperiod duration varied between 300 and 2000 msec. Analysis showed that in addition to the expected effects of age and foreperiod, there were qualitative differences between the performance of adults and children: 5- to 7-yr.-olds reacted quickest after a foreperiod shorter than that required by adults to perform best. Conversely, preadolescents' optimal foreperiod was relatively longer than that of either older or younger subjects. In addition, the youngest subjects showed an inability to maintain preparation as efficiently as older subjects. Implications for the development of response preparation are discussed.     

Perceptual learning by educable mentally retarded, average, and gifted children of primary school age

A match-to-sample task and a preference-ranking procedure were used to provide predifferentiation experiences on a color discrimination for 6- and 8-yr.-old children. The subjects included an educable mentally retarded 8-yr.-old group, an average 8-yr.-old group, a gifted 6-yr.-old group, and an average 6-yr.-old group. Mental age was the best predictor of success on task. A significant interaction of sex and teaching method suggests an advantage of girls in this group in instructional situations in which the perceptual learning task and testing tasks are not exactly the same. Girls did better than boys when a different response for task content was required in testing from that in teaching. Boys and girls performed similarly when the training task was the same as the testing task.     

Human figure drawing size and body image in preschool children from a self-physique perspective

To learn about the relationship between size of human figure drawings and the physiques of children, we investigated body image characteristics in childhood by using the Human Figure Drawing test. Height, weight, Kaup Index (a body mass index for children) and Human Figure Drawing traits (vertical height, horizontal width, waist size, surface area of head, surface area of the self-drawing) were measured for drawings of 122 4- to 6-yr.-old children (62 boys, 60 girls). Analysis showed that boys, who are physically larger than girls, produced self-drawings with somewhat larger surface areas. For vertical height of self-drawings of boys, 4-yr.-olds characteristically made taller self-drawings than 5-yr.-olds. While we hypothesized that taller children would make vertically taller self-drawings, we observed a negative relationship between children's physical height and the vertical height of the self-drawings. 4-yr.-old boys showed the most interest in their own physical height, making taller drawings and in doing so gave a clue to an early childhood feature of body image.     

Movement control and maturation in elementary-grade children.

Serial tapping by 5-, 7- and 9-yr.-old boys and girls, as measured by Fitts' Law, was recorded. 60 Ss performed a reciprocal tapping task and were assessed developmentally via hand-wrist X-rays. No significant relationship was found between the fine motor task and skeletal age. The results of the motor task suggest an improvement in movement time, with age, due to an ability to plan subsequent movements rather than simply an increase in speed of arm movement.     

EMG and motor performance changes with practice of a forearm movement by children

The purpose of this research was to investigate changes in the control of movement, using EMG and kinematic variables, over practice by children. Children in three age groups, 7, 9, and 11 yr., performed 60 trials of an elbow-flexion movement. Correct movements consisted of a 60 degrees angular movement of the forearm in 800 msec. The analysis of biceps brachii and triceps brachii muscle EMG activity, movement displacement and timing error, and movement velocity patterns indicated changes in motor performance with practice. All age groups improved performance with practice and also exhibited a decrease in biceps EMG activity with practice. Only movement-time error and time to peak triceps muscle activity differed between the age groups. The 11-yr.-old group significantly altered the timing of the antagonistic response to stop the movement over the practice session. This change is suggested to be related to the greater information-processing ability of these children and the development of appropriate movement strategies to perform the movement task successfully. Other changes observed in the EMG data appear similar to changes observed in studies of adults.     

Developmental influences on speech-motor equivalence: some implications for articulatory disordered children

The peak amplitude of EMG activity was measured from the orbicularis oris superior (OOS), orbicularis oris inferior (OOI) and masseter muscles for 3 normal 4-yr.-old children and compared to past data gathered on a group of articulatory disordered children, normal children, and adults. The 4-yr.-olds evidenced greater average peak EMG activity than the other groups, suggesting that speech-sound production becomes more efficient with maturation. Also, levels of variability obtained for the younger children were considerably smaller than for the normal speakers across the three muscles, showing that motor equivalence changes with age whereby the flexibility in the control of articulators increases. The coefficient of variation for the OOI muscle for the disordered children, however, was similar to that for the 4-yr.-olds, while the corresponding data for the other two muscles paralleled those for normal ones. These findings were interpreted as reflecting a delay in the development of speech-motor equivalence that affects certain muscles while sparing others.     

Preschool children's social understanding: a pilot study of goals and strategies during conflict situations

This pilot study tested a new enactive measure of social information-processing skills and investigated whether preschool children's goals were related to their strategies during hypothetical conflict situations. Children (13 boys, 12 girls) ages 3 to 6 years (three 3-yr.-olds, three 4-yr.-olds, 11 5-yr.-olds, and eight 6-yr.-olds) engaged in a puppet interview of six hypothetical situations. Significant correlations were found between goals and strategies of the adapted version of Chung and Asher's Children's Conflict Resolution Measure, suggesting that preschool children who endorsed friendship goals tended to select more prosocial strategies (.41). Children who endorsed more retaliation goals tended to select more hostile strategies (.67) but fewer prosocial strategies (-.41), and children who endorsed more avoidance goals tended to select more adult-seeking strategies (.45).     

Labeling, attention and perception, a developmental study

96 7- and 9-yr.-olds were under four experimental conditions. A "distinctive label" group (n = 24) associated four different gender-cued labels with four infants' faces. An "equivalent label" group (m = 24) associated only two of these labels. There were also two no-label groups (ns = 24), "differential perception" and "perception." In the former, perceptual cues were provided; no cues were provided in the latter. The main measure was a test of perception. 9-yr.-olds were not affected by the labels, 7-yr.-olds were but more significantly so during initial trials. It is proposed that perception is affected by labels, learning, and selective attention. These effects are determined developmentally. As age increases the effects of verbal cues diminish and of perceptual cues increase. The findings are related to cross-cultural data, indicating that Israeli toddlers classify according to gender earlier than do American children. This is probably because Hebrew more than English contains distinctive linguistic cues related to sex.     

The Swedish version of the parent-rated Junior Temperament and Character Inventory (J-TCI)

To evaluate the psychometric characteristics of the Swedish version of the Junior Temperament and Character Inventory (J-TCI), it was sent to parents of 9- and 12-yr.-old twins in Sweden. The final number of responders was 196 parents who rated 92 female and 104 male twin pairs. The inventory of one twin, randomly chosen from each pair, was included in the analyses. Reward Dependence, Persistence, and Cooperativeness were scored higher in girls; Novelty Seeking was higher in the 9-yr.-olds and Persistence in the 12-yr.-olds. Pearson's correlations showed that some dimensions were not statistically independent from each other, even if the covariance was moderate. Internal consistency (Cronbach's alpha) was satisfactory for Harm Avoidance, Novelty Seeking, Self-Directedness, and Cooperativeness (.68-.81), while it was lower in those dimensions that had fewer items. The Swedish parent version of the J-TCI shared about the same psychometric characteristics as found in international samples.     

Automatisation deficits in balance for dyslexic children.

Traditional theories of dyslexia have focused on components of the reading process. The Dyslexic Automatisation Deficit hypothesis takes a broader view, attributing deficits to an inability to become completely fluent in cognitive and motor skills. A series of experiments compared the balance of 15-yr.-old and 11-yr.-old groups of dyslexic children and normal children matched for age and IQ under single-task and dual-task conditions. There were no group differences in the single-task conditions. However, introduction of a concurrent secondary task led to a dissociation in that, whereas the balance of normal children was unaffected, the dyslexic children's balance was significantly impaired. It was concluded that the normal children balanced automatically whereas the dyslexic children did not. These results directly support the proposed framework.     

The role of object violation in the development of visual analysis

The present study investigated whether sensitivity to object violations in perception as well as in action would vary with age. Five-, 6-, and 11-yr.-old children and adults solved tasks which involved perception only, motoric indication of parts, actual assembly of parts, and drawing of a violated figure. In perception, object violation was the only factor showing change across age groups, with violations being increasingly noticed. In composition tasks involving motor components, object violation was just one factor besides quantity of parts and type of segmentation contributing to task difficulty and showing increase in performance across age groups. Analysis of object violations in visual structure required abilities similar to those needed when analysing shape interference. Improved visual detection and graphic construction of object violation seemed not to occur because segmentation increased quantitatively but more likely because fast perceptual processes came under scrutiny.     

Speech-motor equivalence in aging subjects'

The peak amplitude of EMG activity was measured from the orbicularis oris superior (OOS), orbicularis oris inferior (OOI), and masseter muscles for three normal, geriatric women (range 70 to 75 yr.) and compared with prior data for a group of normal, 4- and 8-yr.-old children and young adults (range 21 to 29 yr.). The elderly groups' variability across the three muscles paralleled that of the 4-yr.-olds, suggesting that speech-motor equivalence returns to an earlier level of operation in aging speakers. Also, the elderly subjects evidenced reduced levels of average peak EMG activity as compared to those of the other groups. This finding was interpreted as reflecting a loss of general muscle function, a possible concomitant of facial muscle atrophy that accompanies advanced age.     

Developmental differences in children's ballistic aiming movements of the arm

An experiment was conducted to examine the change in the relation between programming and "on-line" correction as a developmental explanation of children's arm movement performance. Each of 54 children in three age groups (5, 8, and 10 yr.) completed two types of rapid aiming arm movements in the longitudinal plane on the surface of a digitizer. Percent primary submovements and timing variability were dependent variables. Analysis suggested that the 5-yr.-olds used "on-line" monitoring during the arm movement and did not perform the movement sequence as a functional unit. Compared with 8- and 10-yr.-olds, the 5-yr.-olds planned a smaller portion of movements, executed the arm movements with more variability in time to peak velocity. The 8- and 10-yr.-olds appeared to plan their movements and execute the sequence as a unit. The developmental implications were discussed.     

Sensation seeking and the use and selection of media materials

175 individuals recruited from urban universities (n=82) and the surrounding community (120 women, 55 men; 82 18- to 25-yr.-olds, 26 26- to 34-yr.-olds, 44 35- to 50-yr.-olds, 23 50 yr. old or over) completed a sensation seeking scale and measures of the frequency with which they used specific media and selected specific television programming, film, and music genres. Regression analyses showed Sensation Seeking to be associated positively with Movie Theatre Attendance and with the Selection of Urban Music Genres. Sensation Seeking was also associated negatively with Selection of Light Film Genres.     

The Development of a Simple Ballistic Skill with and Without Visual Control

80 randomly selected male Ss discriminated the “effort” required to perform a simple 1-handed ballistic aiming task: aligning a Fletcher’s Trolley with a pointer placed at varying distances adjacent to an inclined wooden track. Groups were aged 5-6, 10-11, 15-16, and 18 or more yr., with 10 Ss able to see both hands and target while the other 10 could see neither. A split-plot factorial design was used. On excluding the 5-6 yr.-old “Nonvision” children, the remaining 7 sub-groups were shown to be homogeneous. Mean absolute error scores increased with Distance, and also with a decrease in Age. In the “Non-vision” condition accuracy was reduced still further for all Ss. Age, Vision, and Distance and the interaction of Age with Vision were all significant, p<.01.     

Relationships among age, sex, and depth of sport experience with initial open-task performance by 4- to 9-year-old children.

The purpose of this study was to assess the relative interrelationships of age, sex, and depth of sport experience on initial practice of a soccer task for 46 4- to 9-yr.-old children. Each child practiced 1 transfer trial and 3 blocks of 3 trials. Measures recorded were performance time, goal attainment, and movement accuracy. Multivariate analyses of variance and multiple regressions yielded evidence for (a) a speed-accuracy tradeoff, (b) a relation of age to goal attainment, movement accuracy, and performance time on the transfer trial, and (c) a relation of age with Block 1 performance time. Experience was more related than sex to all variables except movement accuracy in Block 1 and consistency of goal attainment. Conclusions are that age and experience are the most important to the quality of performance, and no constructs were related to consistency on this task for this age group.