| The RAN deficit of DD(Norton & Wolf,2012)is the phenomenon that more time is needed for developmental dyslexia(DD)to accomplish the rapid automatized naming(RAN)tasks compared with their peers.Some researchers thought the difficulty in parafoveal processing was the important reason for the RAN deficit of DD.However,past studies did not consider the the possible influences of some potential factors,such as the influence of the load of foveal processing on parafoveal preview benefit and so on.In this study,we manipulated the types of preview information and the preview duration when previewing.The purpose of this research is to explore the parafoveal preview effects and its cause of DD children in RAN tasks.Two eye-track sub-studies were conducted to investigate the parafoveal preview effects of Chinese DD children in RAN tasks and the reason why Chinese DD children showed various parafoveal preview benefit in RAN tasks.Three groups of children were selected as participants,including children with DD,the chronological age-matched children(CA),and the reading level-matched children(RL).The purpose of study 1 was to investigate the parafoveal preview effects of Chinese DD children in discrete RAN task.Two experiments were performed.In experiment 1,the boundary paradigm was used.In addition,three types of preview information(control character,orthography and phonology)and two priming durations(40ms,60ms)were manipulated.The result showed that there was no significant difference between the DD group and CA group in different types of preview information and durations ? It suggests that there was no significant parafoveal processing difficulty and RAN deficit of DD in the discrete RAN task.In experiment 2,boundary paradigm and four types of preview information(control character,orthography,phonology and identity character)was used in serial RAN such that preview information appeared firstly and target characters appeared only when the foveal processing started.The result showed that the decrease of fixations' durations of DD children were more significant than CA group in preview conditions compared to no preview conditions.It suggests that although larger preview effects were found in DD,DD still showed RAN deficit in serial RAN.The study 2 was to investigate the reason why Chinese DD children showed larger preview effects in RAN task.Two experiments were conducted.In experiment 3a,the parafoveal fast-priming paradigm was used to explore the influence of priming duration on the preview benefit of Chinese DD children.Two types of preview information(control character and orthography)were performed.Besides,four priming durations(40ms,60 ms,80ms and 100ms)were manipulated.The result showed that there was no significant difference of the orthographic negative priming effects among all three groups in different preview durations.It suggested that the orthographic priming effect did not increase with the longer preview duration.In experiment 3b,the parafoveal fastpriming paradigm was used to explore the influence of priming duration on the preview benefit of Chinese DD children.Two types of preview information(control character and orthography)were performed.Besides,four priming durations(40ms,60 ms,80ms and 100ms)were manipulated.The result showed that there was no significant discrepancy of the phonological positive priming effects of all three groups in different preview durations.It suggests that the phonological priming effect did not increase with the longer preview duration.In experiment 4,the boundary paradigm and two types of preview information(control character and masking stimulus)were used to investigate whether the control character would interfere the following foveal processing as a baseline.The result showed that the fixations' durations of targets varied much larger for DD children than CA group in control character condition compared to masking stimulus.It suggests that DD children displayed significant obstruction compared with CA group when the baseline was the control character.Therefore,the larger parafoveal preview benefit of Chinese DD children in RAN task was probably caused by the interference of the control character.In sum,in this study we found that Chinese DD children did show significant RAN deficit and some difficulties in parafoveal processing.It shows that the reason for Chinese developmental dyslexia is complicated and may involve many different processes related to reading. |
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