The Effects Of Font Size And Inter-character Spacing On Sentences Reading Of Chinese Children With Developmental Dyslexia

Reading is an important cognitive activity of human to know the world. For normal readers, it is easy, but not for dyslexic children. Mechanism for this phenomenon is still unclear, but the existing studies show that visual factors play an important role in dyslexics, especially when surrounding around the target stimulus, the recognition of target stimulus will be disturbed, namely Visual Crowding Effect (VCE). Existing studies shows that VCE have more effect on developmental dyslexics than normal readers, but these studies are based on the western alphabetic writing, the structure of Chinese characters is very complicated, which is different from western alphabetic writing. Thus the results from western studies cannot be directly applied to chinese developmental dyslexics, only be used for reference. Font size and inter-character spacing are important factors of VCE. Therefore, the purpose of this study is to explore the effect of font size and inter-character spacing on the chinese developmental dyslexic children, then choosing the appropriate way of text presentation for chinese developmental dyslexic children.The purpose of study 1 is to screen chinese developmental dyslexic children(DD). Using the assessment of vocabulary of chinese characters for primary school and Raven Standard Progressive Matrices Test, we selected 25 developmental dyslexics(DD),27chronological(CA) and 25 reading level-matched (RL)children.Two experiments are included in the study 2. The purpose of Experiment 1 using PsychoPy2.0 is to explore the effect of font size on DD, then comparing with CA and RL. Five types of font size (12、 14、16、18、20pt) were used. Results show that DD was found significantly slower reading speed. For DD, there is no difference among the speed under the condition of 14,16and 18pt.The speed under the condition of 14,16 and 18pt is faster than others significantly. There is no difference between the score of subjective assessment under the condition of 14 and 16pt.The score of subjective assessment under the condition of 14 and 16pt is larger than others significantly.The purpose of Experiment 2 using EyeLink1000 is to explore the effect of inter-character spacing on DD, then comparing with CA and RL. Six types of inter-character spacing (-1/4、0、1/4、1/2、 3/4、1 character) were used. Results showed that, in contrast with CA and RL, DD was found significantly slower reading speed, more reading time and average fixation duration, and more number of fixation, saccade, and regression; Under the condition of-1/4 inter-character spacing, DD showed the longest average fixation duration and the smallest average saccade amplitude; while under 1 spacing condition, DD showed the most number of fixation, saccade and regression.In summary, The current study suggested that:1) Eye movement pattern of DD is different from CA and RL on the main eye movement indicators, such as fixation duration, the number of fixation, saccade and regression.2) The effect of font size have significant effect on sentences reading in DD. Dyslexics reading can be modulated by the font size.Whether the font size is too large or small, it will not benefit the reading.3) The inter-character spacing have significant effect on sentences reading of DD. Whether the inter-character spacing is too large or small, it will not benefit the reading.