Verbal Fluency Development Across Childhood: Normative Data from Brazilian-Portuguese Speakers and Underlying Cognitive Processes.
Verbal fluency (VF) tasks are widely used to investigate children's lexical knowledge and executive functions skills. Consistency of measurement of the strategic retrieval components is still an issue and performance of Brazilian-Portuguese speaking children are currently not available. A cross-sectional study investigated the effects of age, school type (public × private) and the influence of language, memory and inhibitory control on VF. We assessed 414 Brazilian children, aged 6-12, in the number of words produced and both clustering and switching components, with two measures of VF: letter (LVF) and semantic (SVF). Analysis of the number of words produced showed a significant increase between 6-8-year-olds, 9-10-year-olds and 11-12-year-olds in SVF, while in LVF, the differences were significant only in the later age group. In SVF, the numbers of clusters and switches increased with age, whereas in LVF, the number of switches increased in all age groups, but clusters increased only in the older group. Structural equation model analyses showed that oral and written language, verbal memory and inhibitory control are associated with VF performance and IQ, while age mediated VF performance. The results indicate a different development pattern between LVF and SVF in the number of words produced and in clustering and switching, with the latter predicting VF performance in words produced. VF development is shown to depend on language, memory and inhibitory control. Our results have important implications to clinical neuropsychology.