On the relation between single word and multiple word processing during learning to read

The present study investigates the development of single word processing and multiple word processing skills in French-speaking children from Grade 2 to Grade 6. One hundred and fifty children participated in two tasks: a Lexical Decision Task (LDT) and a Grammatical Decision Task (GDT). The LDT was used to test single word processing abilities whereas the GDT was used to test multiple word processing abilities. Signal detection theory analysis revealed that all children performed well in the LDT, whereas a different pattern emerged in the GDT, where only Grade 4 and Grade 6 children performed above chance in this task. Then, a cluster analysis was used to investigate the relation between LDT and GDT sensitivity. The analysis revealed two clusters that differed in reading fluency and sensitivity in both tasks. Children from Cluster 2, who exhibited the highest sensitivity in the LDT, were the only ones to perform on average above the chance level in the GDT. Moreover, a strong correlation (r = .64) between LDT and GDT performance was found in this group. Finally, we found that a sensitivity of 1.95 in the LDT almost perfectly predicted cluster membership. We estimated that such sensitivity is achieved at Grade 3, suggesting that the ability to process multiple word sequences first requires sufficient efficiency in processing words in isolation. Once this turning point is reached, single word processing skills support the development of multiple word processing, which could take several years to mature fully.