Effect Of Space On Chinese Developmental Dyslexic Childen During Digits RAN:Evidence From Eye Movements

Rapid automatized naming (RAN) is a simple task of rapidly naming digits, or letters, objects, colors, etc., displayed in a matrix-like arrangement, which has been used as a very reliable predictor of reading and development dyslexia for many years.The purposes of the research were to investigate whether the space can improve children RAN performance, and to explore the each impact of two functions of spaces. In current study, two types of digit-RAN (taskl:naming digits one by one, or task2: naming digits by tens) were adopted. In taskl digit-RAN, we could explore the pure effect of reducing of visual crowding. While the task2 RAN is analogous to reading Chinese, so that we could tested the both effect of spaces.Two studies, including four experiments, were carried out.In experiment 1a of study 1, Using an Eyelink1000, we tested 10 developmental dyslexic children (DD) matched by 10 chronological (CA) and 10 reading-level (RL) controls during two digit-RANs. The type of space in two digit-RANs were manipulated:digit strings with no space (a), digit strings with spaces between digits (b), digit strings with spaces between pairs of digits (c). Results showed that, in both digit-RANs, three groups of children used the least time to name digits in the condition (c).Their average fixation duration in the (c) was shorter than in the condition (a), their total number of fixations in the condition (c) was less than in the condition (b); but especially so in task 1 RAN.In experiment 1b of study 1, the eye movements of 7 DD with 7 CA children during RANs were recorded. The types of space in two digit-RANs were:the condition (a), the condition (b). the condition (c). digit strings with spaces between pairs of digits-Ⅱ (d). The results showed that, two digit-RANs under the condition(c) were both easier to name than the other conditions. Both groups of children used the least time to name digits in the condition (c).Their total number of fixations in the condition (c) was the least and the average fixation duration in the conditions (c) was shorter than in the condition(a). The total number of fixations of DD children was more than of CA children.Study 2 was to explore the effect of segmentation by highlighting on both groups of children during task 2 digit-RAN. Two experiments were carried out.In experiment 2, the types of marking boundary by highlighting were manipulated: digit strings highlighted correctly to meet the mission requirements (e), normal digit strings (f), digit strings highlighted incorrectly to meet the mission requirements (g). By comparing eye movements of 5DD children and 8 CA children, the results showed that, on the average fixation duration and total number of fixations, there were no differences among the three conditions. The total number of fixations of DD children was more than of CA children. DD children had the shortest total duration in the condition (g), however CA children had the same total duration in three conditions.In Experiment 3, the difficulty of digit-RAN was manipulated. There were a more difficult ambiguous digital material and an easier digital material by marking boundary of the difficult ambiguous one. By comparing eye movements of 6 DD children and 8 CA children, the results showed that, in the easy digit-RAN, the total fixation duration, average fixation duration were both less than in the difficult digit-RAN. The total number of fixations of DD children was more than of CA children.In summary, the conclusions are as following:(1) In two digit-RANs, the performances of all children were facilitated by spaces.(2) The effect of boundary segments of spaces was larger than the effect of reduction of visual crowding.(3) It was marking boundary by highlighting to reduce difficulty of materials that improving DD children and CA children.