Conditions for Effective Knowledge Acquisition.

Abstract

In three distinct yet related studies, I examined the conditions necessary for children’s normal cognitive development and growth. In the first essay, I explored the trajectories of children’s mathematics and reading comprehension scores as a function of early maternal age, controlling for maternal background and present family circumstances. I made a unique contribution by utilizing growth curve modeling and found, in contrast to literature suggesting a spurious relationship, that there is a negative impact of early maternal age on the two relevant outcomes. The extent of this negative effect, however, varied both between the two outcomes and as a function of age. For instance, there is no effect of early maternal age on initial mathematics scores, but there is an effect of early maternal age on initial reading comprehension scores. The second study, in which I utilized a regression technique that combines mediation and moderation analysis into a single model, and in which I also treated maternal intelligence as the proximal predictor of child outcomes, revealed that the mediating impact of SES on the maternal intelligence-child outcomes relationship varied as a function of the level of maternal intelligence. The positive effect of increased SES on children’s academic ability decreased as the cognitive ability of mothers increased such that children in low IQ households benefitted most from improved SES while children in high IQ households benefitted somewhat less. Focusing on valid and reliable measures of maternal and child IQ, the third study explicated the extent to which treatment-effect heterogeneity by maternal IQ class was present in a well known early childhood education randomized intervention. Results revealed that the largest returns to treatment group assignment were present among the most disadvantaged youngsters (i.e., those whose mothers had an IQ score on the Wechsler scale in the mildly mentally retarded range of 50 – 75, taking into account measurement error). Children of higher IQ mothers assigned to the experimental group performed better in terms of their raw scores than did their peers born to low IQ mothers, but their gains over their control group counterparts were lost by middle childhood.