Developmental dyslexia: How taxonomic and thematic organization affect working memory recall.

Semantic long-term memory (LTM) representations can be distinguished in two main classes: taxonomic (i.e., abstract) and thematic (i.e., concrete, experiential). In typically developing children, taxonomies are usually acquired after thematic representations. In the current study, we investigated how LTM semantic representations modulate working memory (WM) recall in children with developmental dyslexia (DD). A sample of children with DD from primary and secondary school paired with a control group for age, gender, schooling, and IQ was administered a semantic WM (SWM) dual task. Here, children had to listen to groups of lists composed of words semantically related (taxonomic, e.g., shop- drugstore-coffee; or thematic, e.g., light-heat-fire) or arbitrarily related, and afterward to recall the last words among each group. Both taxonomic and thematic organizations supported recall in the two groups of children. More specifically, data showed that in typically developing children the taxonomic organization boosted WM recall (vs. the thematic one). On the contrary, in children with DD, the taxonomic organization did not better support recall and yielded effects similar to thematic organization. In children with DD, abstract taxonomic knowledge seems to be less frequently used than thematic knowledge. Findings contribute to sketch memory functioning across different memory systems in DD.