Word and pseudoword superiority effects on letter position processing in developing and skilled readers

Studies have shown that letter position processing changes as reading develops. Whether these changes are driven by the development of the orthographic lexicon is currently unclear. In this study, we administered a novel variant of the Reicher-Wheeler task to children aged 7-12 years (Experiment 1) and adults (Experiment 2) to clarify the role of the developing lexicon in letter position processing. The task required participants to report the identity of a letter at a specified position within 3 orthographic contexts: anagram words (e.g., slime - which has the anagram partner, smile), pseudowords (e.g., blire -brile), and illegal nonwords (e.g., bfgsv - bsgfv). The influence of a reader's whole-word orthographic representations was investigated by comparing the performance of words to pseudowords (word superiority effect or WSE), and the influence of their knowledge of orthotactic constraints was investigated by comparing pseudowords to illegal nonwords (pseudoword superiority effect or PSE). While the PSE increased with developing orthographic skills (as indexed by irregular word reading) in primary schoolchildren, the WSE emerged only in adult readers. Furthermore, the size of the WSE increased with orthographic skill in adults. The findings are discussed in regards to current models and theories of visual word recognition and reading development.