Subgroups in cognitive development: Distribution of Brazilian students aged 7–14 years.

Abstract

This study explored subgroups with similar patterns of cognitive functioning throughout normal development. The sample consisted of 350 healthy students of both genders, aged 7–14 years old, from low-income Brazilian families. Instruments included the Rey-Osterrieth Complex Figure, Stroop test, letter and semantic verbal fluency, and the Rey auditory-verbal learning test. A hierarchical cluster analysis was used as an exploratory method, and a nonhierarchical cluster analysis was used as a confirmatory method to classify the subjects in different groups according to their global functioning, organization, memory, and attention profiles. The ages and performance levels of each group were compared using ANOVAs. Post hoc procedures tested inter- and intragroup differences. A classification model was proposed, examining which factors contribute to the peculiarities found in each cognitive profile. A 4-group division demonstrated to be the best solution to classify cognitive profiles in this sample. It was found a significant effect of group for age, with the older adolescents systematically outperforming younger children in terms of global functioning. Secondarily to the global classification, the performance on organization scores is the bigger distinguishing factor between groups. Memory and attention variables appear to cause subtler and less relevant changes to overall functioning. Additionally, attentional ability was more useful in distinguishing the cognitive profiles of younger children, which have accentuated lower performance in this ability. These results are consistent with neuropsychological literature, which indicates a large range of variability in cognitive profiles during development, even to subjects in the same age group.