Castles, A. 1, 2 & Kohnen, S. 1, 2
1 Macquarie Centre for Cognitive Science, Macquarie University, Sydney, Australia
2 ARC Centre of Excellence in Cognition and its Disorders, Macquarie University, Sydney, Australia
Several cases of developmental letter-position dyslexia have recently been reported, in which the primary symptom is a preponderance of letter-position errors on “migratable” words, (e.g., ‘beard’ read as ‘bread’; Friedmann & Rahamin, 2007). This reading profile has been attributed to a specific impairment in the encoding of letter position. However, it is difficult to evaluate this claim in the absence of data on the extent to which normally-developing readers make such errors and how they relate to other aspects of reading progress. In this study, children in Grades 2, 3 and 4 were tested on migratable words, as well as on letter processing, lexical and nonlexical processing, and lexical “guessing”. Errors on migratable words were prevalent in developing readers, and the proportion of such errors did not decrease with increasing Grade level. However, they were not associated with deficits in other reading processes or with lexical guessing. We conclude that a reading profile characterised by a high proportion of migration errors may not necessarily be indicative of a reading disorder and may reflect an optimally-tuned reading system.