The contribution of executive functions to naming digits, objects, and words

Although it is established that reading fluency is more strongly related to serial naming of symbols than to naming of isolated items ( serial superiority effect ), the reason for the difference remains unclear. The purpose of this study was to examine the role of executive functions in explaining the serial superiority effect. One hundred seven Grade 6 Greek children were assessed on serial and discrete naming (digits, objects, and words), executive (inhibition, shifting, and updating) and non-executive tasks (simple choice reaction), and on a serial Rapid Alternating Stimuli task. Reading fluency correlated more strongly with serial naming than with discrete naming, consistent with the serial superiority effect. In hierarchical regression analyses, executive measures failed to account for variance shared between serial naming and reading fluency. In confirmatory factor analyses, including a discrete and a serial factor for the naming tasks, variance in the executive tasks not shared with simple choice reaction was not associated with the serial factor. Thus, the executive tasks failed to account for the serial superiority effect. The high correlation between the simple choice factor and the discrete naming factor suggests that method variance partially underlies the observed relationship between executive function tasks and word reading. We argue that the distinction between serial and discrete dimensions indicates that internally regulated cognitive control is crucial for the serial superiority in naming symbols and words.