Early lateral preferences and mental processing trends in black preschoolers.

[摘要] The current study adopts a developmental neuropsychological perspective, an approachwhich does not imply brain dysfunction but rather the principle of understanding the generalrelationship hetween brain growth and behavioural changes and the effect of environmentalfactors in children. A neuropsychology of normal development would seem to be anappropriate initial prerequisite if we are to understand the effects of brain insult or diseasein the developing child. A modest aim was to acquire a fundamental understanding ofemerging skills in black preschool children, starting with the most basic, the development oflateral preferences. This area was selected (a) as a departure point because of its locationwithin the broad area of cerebrallateralization and (b) the opportunity it provided to explorethe children's mental processing skills within the same theoretical perspective.The purpose of the present study was the longitudinal investigation of lateral preferencesin a sample of Soweto children at three and five years.and information processing skills inthe same sample at five years. Three hundred and thirty-five children, 170 girls and 165boys, were sampled with the assistance of the Birth to Ten project.a longitudinal study ofgrowth, health and development of children living in the Johannesburg Metropolitan area overa ten year period, 1990 to 2000. The children were assessed prior to starting school inJanuary, 1996. A descriptive approach was adopted in explaining the patterns of handedness,footedness and eyeness. The findings showed that the patterns for handedness reflected theexpected rightward direction at both ages although the degree to which preference has oeenestablished was weaker at five years than that reported in other studies with children ofsimilar ages. Thirty-nine percent of the sample were mixed-handed at five years,only 3%were mixed-footed and 5% showed mixed-eyeness,At five years Simultaneous and Sequential information processing skills were assessedwith the Kaufman Assessment Battery for Children (K-ABC). Factor analysis revealed a twofactor solution broadly supporting the presence of the two processing styles. However the twocoding processes were differentially distributed throughout the sample showing significantdifferences. More specifically.it was found that 34% of the children presented profiles of bothprocessing styles that were below the group mean;31 % showed profiles where one or othercoding style was below the group mean;23 % of the children portrayed processing profilesabove the group mean. Thirty-nine children (12 %) presented patterns of processing that wereabove the group mean but were highly developed in one or other processing style. Each ofthe profiles that emerged were grouped and considered separately.Cognitive tasks involving verbal fluency, naming skills,draw-a person,basic perceptualknowledge,basic literacy.plus lateral preference information such as handedness direction,handedness consistency and handedness skills were appended to all the groups. Low scoresin processing styles were found to be associated with poor verbal skills, low mental age,poorperceptual and basic literacy knowledge,poor hand skill performance,and greater (but nonsignificant)numbers of mixed-handers. The lowest scoring group also contained the majorityof male left-handers. One of the highest scoring groups showed the strongest lateralizingpatterns although the numbers were small (n= 11). Girls with above average sequential skillsalso scored highly on verbal fluency (p < .05) and hand skills (p < .05). Boys in this groupshowed the strongest degree of right-handedness (p < .05). In the four lower performancegroups,background variables such as type of preschool experience (p <.001),the presence ofbooks in the home (p < .05) and mothers level of education (p <.001) were found to besignificant. A regression model which incorporated environmental, epigenetic, cognitive andmotoric factors was found to be the most viable in predicting processing skills.

[发布机构] University of the Witwatersrand