No abstract

To determine the optimal time for testing the association between personality traits and cortisol levels, and the number of sampling days needed for reliable results to be obtained for preschool-aged children, ambulatory salivary sampling for cortisol was performed on 39 preschoolers at four different times for 10 consecutive school days. A repeated-measure ANOVA revealed a significant day effect, time effect, and day by time interaction. Further tests of day effect revealed that within-subject cortisol levels differed significantly in the early morning, early afternoon, and late afternoon cortisol data, but not in the late morning; group average levels of cortisol assessed in the early mornings are significantly different among the days, so are the ones measured in early and late afternoon. Mid-afternoon cortisol levels showed the most significant day effect and the highest correlation with internalizing disposition. In addition, the probability of finding significant correlations between cortisol levels and internalizing disposition increased with a greater number of aggregated cortisol measures. The tentative conclusion is that to avoid under-representation of the correlations between cortisol levels and personality variables, both sampling time selection and data aggregation are important.

No abstract

Based on data collected from 211 elementary school children in central Taiwan over four years, the role of temperament in science achievement was examined with multivariate analysis of covariance (MANCOVA) with repeated measures design. The results revealed that the students' science achievement is stable over time. The task orientation characteristics (i.e., distractibility, hyperactivity, and persistence) identified by previous research as important in mathematics and reading achievement are not consistent with the findings of this study that although the impacts of distractibility and persistence are significant, the simple effect of activity level on science achievement was not significant. However, the interaction effect of activity level and persistence is significant. Further break down analyses conducted to pursuit the interaction effect revealed that: (1) persistence has a consistent significant positive effects on all children over the years, except for the ones with high activity level (the upper 25th percentile); and (2) activity level has significant negative effects on high persistence (the upper 25th percentile) children only, and the interaction effect of activity level increases over time-the older the child the more significant the influence. Also, the tendency of approach/withdraw has significant impact on science achievement The educational implications of the findings include: (1) teachers of high activity students with high persistence may need to consider the match between children's interests and contents of instruction; (2) a good match between children's individual differences in distractibility, persistence, and approach need to be considered in contents, expectations, and interactions of the instruction.

The goal of this study was to investigate parental involvement as an etiologic moderator of oppositional defiant disorder (ODD) during middle childhood. Previous studies examining the influence of genetic and environmental factors on ODD have not considered whether and how these factors might vary by parental involvement. We thus conducted a series of “latent G by measured E” interaction analyses, in which measured parental involvement was allowed to moderate genetic, shared, and non-shared environmental influences on child ODD. Participants include 1027 twin pairs (age ranged from 6 to 11 years old) from the Michigan State University Twin Registry (MSUTR). Results did indeed suggest that the etiology of ODD varies with maternal involvement, such that genetic influence on ODD became more prominent as maternal involvement decreased. However, these results were specific to children’s perceptions of maternal involvement and did not extend to maternal perceptions of her involvement. There was no evidence that paternal involvement moderated the etiology of ODD, regardless of informant. The different results found in twins’ and parents’ data is consistent with previous research that children may have different perceptions from parents about their family relationships and this discrepancy needs to be taken into account in future research.