Neurophysiological Evidence For The Influence Of Phonological And Semantic Neighbourhood Densities On Word Production In Children

Abstract

Neighbourhood density’ refers to the phonological and semantic connectedness of words in the mental lexicon. Phonological neighbourhood density (PND) in particular has been identi ed as a predictor of vocabulary development (Storkel, 2009). For most children, as the number of low PND words increas- es so does the size of the expressive vocabulary, but late talker children seem to be unable to make this transition since they continue to use high PND words although their receptive vocabulary is com- prised of both high and low PND words. These nd- ings indicate that the production of high PND words may place a reduced demand on underlying pro- cesses of speech production compared to low PND words. The present research addressed this issue by investigating the effect of PND on the cognitive processes involved in word production in children using electroencephalography (EEG). EEG allows the tracking of underlying processing differences across words during word production (Laganaro, Tzieropoulos, Frauenfelder, & Zesiger, 2015). The in uence of semantic neighbourhood density (SND) was also examined, to reveal whether words with different phonological densities are processed differently depending on their semantic density. To this end, EEG data were recorded from healthy English speaking 5-year-old children who named pictures varying in PND and SND. Findings indicate that children process low PND words with more cognitive effort than high PND words during the underlying process of phonological encoding. An interaction between SND and PND during phono- logical processing suggests a facilitative in uence of high SND when PND is low. These ndings show that PND and SND modify the underlying processes of word production in children, providing new in- sights into the impact of PND and SND on informa- tion retrieval, which can support the development of adequate therapeutic interventions. References Laganaro, M., Tzieropoulos, H., Frauenfelder, U. H., & Zesiger, P. (2015). Functional and time-course changes in single word production from childhood to adulthood. NeuroImage, 111, 204–214. Storkel, H. L. (2009). Developmental differences in the effects of phonological, lexical and semantic variables on word learning by infants. Journal of Child Language, 36(2), 291–321.