Development of Visual Analysis and Orthographic Input Lexicon in Children with Developmental Dyslexia

—Evaluation Using a Character/Non-Character Decision Task and a Lexical Decision Task with Kanji Stimuli—

Abstract

We investigated development of visual analysis and orthographic input lexicon in children with developmental dyslexia, using a character/non-character decision task and a lexical decision task with Kanji stimuli. In the character/non-character decision task, the dyslexia group made significantly more errors for real characters than the control group, whereas there was no significant group difference for non-characters which were visually similar to real characters. In the lexical decision task, the dyslexia group made more errors than the control group for words, pseudohomophonic nonwords, and nonpseudohomophonic nonwords which were visually similar to words. In contrast, such a significant group difference was not observed for nonpseudohomophonic nonwords which were visually dissimilar to words. These results suggest that the children with developmental dyslexia in this study did not develop visual analysis and orthographic input lexicon to the extent of the control group.