Cognitive precursors of the developmental relation between lexical quality and reading comprehension in the intermediate elementary grades.

In a longitudinal study, we investigated how cognitive precursors (short-term memory, working memory, and nonverbal reasoning) influence the developmental relation between lexical quality (decoding and vocabulary) and reading comprehension skill in 282 Dutch students in the intermediate elementary grades (mean age at start Grade 4 was 9; 7 years) as these grades mark an important transition point in the development of reading comprehension skill. Analyses revealed strong autoregressive effects for the linguistic measures. Moreover, evidence was found for a reciprocal relation between vocabulary and reading comprehension. Direct concurrent relations were evidenced between short-term memory and decoding, and between working memory and reasoning, on the one hand, and reading comprehension and vocabulary, on the other hand. Finally, we found direct and indirect influences of nonverbal reasoning and working memory capacity on reading comprehension and vocabulary development. The results highlight the importance of both lexical and cognitive factors in reading comprehension development.