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.     

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.     

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.     

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.     

Developmental changes in consistency of preferential feeling for peers and objects around age four

When do young children come to have an individual mental image of each peer? Forming a stable impression of each person requires maturation of at least two cognitive abilities, inferring the other's mind and episodic memory. According to past studies, the critical period for both these abilities is around age four. Thus, it was hypothesized that the child begins to form a consistent mental image of each peer at or after age four. To test this hypothesis, the temporal consistency of preference for peers was examined in 3-, 4-, and 5-yr.-olds. Each subject was asked "Who do you like better than others in this class?" once a week for three times (Study 1). The results indicated that most of the 3-yr.-olds answered different names as their favorite friends or nonsense things inconsistently week by week, whereas older children tended to answer the same names across weeks. However, changing the question to "Which object do you like best of these alternatives?" dramatically changed the response pattern (Study 2): preferences among nonhuman objects (playthings) were temporally consistent even for 3-yr.-olds. These results indicate that children before age four do have a temporally consistent feeling toward general objects but do not have a consistent firm feeling about personal relationships among peers. The results are discussed in relation to the critical developmental changes about age 4 in other cognitive abilities.     

Asymmetric recognition of pictures of cats as a function of age in 4-, 5-, and 6-year-old children

In the present study it was investigated whether children recognized deletions more accurately than additions in pictures of animate objects as a function of age between 4 and 6 years. Children, presented pictures of cats with features added to or deleted from the original pictures, judged whether the pictures were the same or different as those in a test of recognition. Analysis showed both 5-yr.-olds and 6-yr.olds discovered deletions more accurately than additions. This asymmetric effect is in accord with that of adults, with whom the same stimuli were used in earlier research, but are contrary to previous studies in which additions were recognized more accurately than deletions when inanimate objects were stimuli. Asymmetric effects, that is, greater recognition accuracy for deletions may be related to children's being uncomfortable about modified pictures of animals.     

Age differences in integration of components of a motor task.

To study effects of practice on the ability of 6-, 11-, and 18-yr.-old Ss to integrate the components of the Rho task 3 groups of 50 boys performed 30 consecutive trials. (a) With practice all age groups improved in total movement time; (b) 11-yr.-old Ss attained the 18-yr.-olds' level of performance in both components, initial differences existing only the linear component; (c) relative to the 18-yr.-old Ss, the 6-yr.-olds achieved proportionally less improvement in the linear component; (d) unlike 11- and 18-yr.-old Ss, the 6-yr.-olds evidenced increasing specificity of task components across trials. Unlike the two older age groups, the 6-yr.-old Ss were unable to achieve a high degree of integration of task components. The findings were discussed in light of Pascual-Leone's neo-Piagetian model of learning and development.     

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.     

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).     

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.     

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.     

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.     

Visual decentration: from stereometric points to planeometric forms.

19 3-yr.-olds chose to put blocks together to produce good continuation across stereometric edges. 4 mo. later they began to produce good continuation across planeometric edges. A group of 15 4-yr.-olds chose to produce symmetrical forms rather than simply to align edges. Symmetrical form was produced across planeometric surfaces but not across stereometric contours. These data suggest that visual decentration is first a shift from looking at single points touched to single points displaced from touch and, at a still later age, a shift to the organization of many points. The failure of the older group to produce a symmetrical form across stereometric contours could have resulted from the cultural press to attend to planeometric information.     

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%).     

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.     

Use of subjective estimation in motor skill tests of young children: judgment based on observation of behavior in daily life

This study assessed what motor skill tests were appropriate by observing 636 young children's behavior in daily life (low-aged classes, M = 3.7 yr.; middle-aged classes, M = 4.7 yr.; high-aged classes, M = 5.7 yr.). A homeroom teacher and an assistant teacher estimated motor achievement as pass-or-fail, and then judged pass-or-fail based on practical testing. Estimate-re-estimate agreement, interrater agreement, and agreement between estimated values and measured values were examined for 27 items, e.g., skipping, bouncing a ball, and turning on one leg. Estimate-re-estimate agreement was high on the whole. Interrater agreement ranged from 34% to 100% for 3-yr.-olds, 21% to 100% for 4-yr.-olds, and 89% to 100% for 5-yr.-olds. Agreement between estimated values and measured values greater than 80% was found in most items for 5-yr.olds (14 items). After examining the above-mentioned agreements, 26 items were selected as possible tests to judge motor development, using a pass-or-fail, from the observation of young children's behavior in daily life.     

Development of children's mental representations: effects of age, sex, and school experience

In the present study mental representations in drawings by 158 young children, ages 2 1/2 to 6 yr. old were analysed. The aim was to investigate whether the accuracy of mental representations increased with age and how this development progressed. Also tested were whether the inferred mental representations differed for boys and girls and whether preschool experience affected the drawings. As expected, mental representation increased in complexity with age as measured by Goodenough's score, and girls' mental representations (drawings) were significantly more elaborate than boys. Moreover, attending school early seemed to affect mental representations of the 3-yr.-olds but not the 4-yr.-olds. Results are discussed in terms of internal and external factors in mental representation in drawing a man.     

Normative data for Raven's Coloured Progressive Matrices scale in Yemen

Results are reported for a standardization sample of 986 6- to 1-yr.-olds for the Coloured Progressive Matrices in Yemen. Younger children performed better than older children relative to British norms, and there was no significant sex difference in means or variability. In relation to a British IQ of 100 (SD=15), the sample obtained an average IQ of approximately 81.     

Life-span changes in the copulatory behavior of male rats (Rattus norvegicus)

The copulatory behavior of 5-, 10-, 15-, and 20-month-old sexually naive male rats (Long-Evans) was studied during 2-hr tests with receptive females. There was no apparent change in sexual arousal as measured by latency to initiate copulation across age, with subjects from all groups exhibiting comparable latencies to first mount and first mount with intromission. The numbers of ejaculations achieved were also similar across ages. Significant age differences were found for frequency of mounts, with 20-month-olds having the highest mean frequency. The persistent mounting by older males appeared to account for significant group differences in interintromission interval and ejaculation latency. It is suggested that motor deficits may impair the ability of older males to achieve intromission, increasing the number of mount bouts as well as the number of mounts per bout, thus extending the length of each copulatory series.     

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.