Growth and Cognition in Brazilian Schoolchildren: A Spontaneously Occurring Intervention Study

Abstract

This study examines the effects of dietary, cultural, and educational intervention on physical growth and cognition in Brazilian children aged from 7 to 10 years. A group of 38 domestic servants' children who had resided and studied for an average of three years in upper-middle class environments were compared with 88 upper-middle class children and 100 slum-dwelling (favela) children using the following measures: weight-for-height, height-for-age, Goodenough-Harris Drawing Test, the Brazilian Non-verbal Intelligence Test (INV), Raven Coloured Progressive Matrices (CPM), WISC-R Coding and Block Design subtest. Although domestic servants' children were significantly taller and heavier than their group of origin (slum-dwelling children) they continued to be significantly shorter than the middle class. Domestic servants' daughters scored significantly better than their slum-dwelling counterparts on cognitive tests measuring speed and accuracy (WISC-R Coding) and analogical reasoning (Raven Coloured Progressive Matrices), however, girls from both lower socioeconomic groups were similar in their performances on the Goodenough-Harris Drawing Test, Non-verbal Intelligence Test (INV), and WISC-R Block Design subtest. Domestic servants' sons were similar to slum-dwelling boys in performance on all cognitive measures. The length of time domestic servants' children had resided in middle class homes was positively and significantly correlated with their weight-for-height and two of the five cognitive tests. Among domestic servants, mothers' egalitarian sex role and less orthodox religious attitudes were positively correlated with children's cognitive performance. The experience of living and studying in a middle class environment resulted in greater gains in physical than in cognitive development.