关键词: 发展性阅读障碍, 空格, 拥挤效应, 眼动

Abstract: In alphabetic languages, some researchers suggested that, increasing the size of the space between the letters and words in text can facilitate dyslexic children’ reading performance by reducing the effects of visual crowding. However, the text in Chinese is usually a sequence of box-like pictorial symbols (characters), and these characters often combine with adjacent characters to form a word. Particularly, the boundaries between words are not demarcated using spaces or other visual cues. Some previous research suggested that adding spaces between Chinese words can facilitate the performance of typically developing readers and second-language learners. But the potential benefits of adding spaces to text for Chinese dyslexic children are still unknown. Accordingly, in the present study, we investigated the benefits for developing dyslexic children when they read the sentences which were inserted spaces between the characters or words. Eleven dyslexic readers (fifth grade), 15 age-matched controls (typically developing fifth graders) and 13 reading ability-matched controls (typical developing third graders) from a primary school, screened by five tests, including text comprehension, literacy-capacity test, orthography test, phonetic transcription test, and rapid naming test, took part in the current study. Texts were presented normally, or with spaces between all characters, or between character pairs that combined to form either words or non-words. Eye movements were recorded by a SR research EyeLinkⅡ eye tracker while the children were reading. The results showed that inserting spaces between words or characters reduced fixation duration in comparison to normal text for readers from all groups. However, whereas for the age- and ability-matched groups this was largely offset by an increase in the number of fixations and regressions in these conditions, this was not the case for the dyslexic group, leading to a reduction in reading times in the character- and word-spaces conditions in comparison to the normal text for this group. Hence, compared to normal text, increased spacing showed no overall facilitation for typically-developing readers, and incurred a cost for all readers in the non-word condition. But clear facilitation was observed for dyslexic readers when spaces were added between characters or words in sentences. Therefore, the results indicate, for the first time, that increased character spacing can benefit the reading performance of Chinese readers with developmental dyslexia. This benefit may arise from the reduced effects of visual crowding.

Key words: Developmental Dyslexia, Space, Visual Crowding, Eye movements