汉语发展性阅读障碍儿童的视知觉学习*

研究采用知觉学习经典范式中的视觉搜索任务探讨汉语发展性阅读障碍儿童的知觉学习过程。研究考察了阅读障碍儿童与正常儿童在简单搜索任务、复杂搜索任务和限制时间的复杂搜索任务上的知觉学习特点。结果发现，阅读障碍儿童在复杂搜索任务中初始搜索时间显著长于正常控制组；在限制时间的复杂搜索任务中更进一步发现阅读障碍儿童的反应正确率显著低于正常控制组儿童；而且两组儿童视觉搜索任务的正确率与汉语阅读的识字量成绩存在显著相关。上述结果表明，汉语发展性阅读障碍儿童存在复杂搜索的知觉学习缺陷，这种缺陷可能在某种程度上与儿童的阅读技能发展有关。

Visual Perceptual Learning in Chinese Developmental Dyslexia

As to the origin and mechanisms of developmental dyslexia, nonlinguistic framework proposes that the phonological and other deficits at the linguistic level may stem from more fundamental deficits in sensory information processing, including acoustic-auditory and auditory temporal processing and visual perceptual processing. Previous studies have shown that visual perceptual deficits of dyslexic children may stem from the deficit in processing more basic visual attributes, as basic visual features are fundamental to higher-level visual processing. Perceptual learning is the improvement of perceptual performance as a function of training (Gibson, 1969), which has been found in various visual tasks involving basic visual features. Here, using visual searching tasks, the main purpose of the present study was to investigate to what extent dyslexic children would show deficits in perceptual processing and learning and whether these deficits are related to their performance in linguistic tasks. Eighteen participants, 9 with dyslexia, 9 chronological age- and nonverbal IQ-matched control children, were screened from a large pool of students in 3, 4, 5 grades with the standardized Chinese written vocabulary test, the reading fluency test and the Raven’s Standard Progressive Matrices test. We tested 9 children in dyslexia group and 9 age-matched children in control group with a parallel search task, a serial search task and a serial search task in restricted time. Study 1 utilized a parallel searching task to examine whether there is a deficit in the basic searching processing and learning in dyslexia group. Study 2 used a serial searching task to explore whether there is a deficit in more complex searching processing and learning. Study 3 adopted a serial searching task with restricted time to investigate whether the ability of serial searching processing will be affected by the restricted time. The results showed that there was no difference between dyslexics and control children in parallel searching task, however, children with dyslexia had significantly longer reaction time than normal children to retrieve the target stimuli in serial searching processing. In addition, the searching accuracy was significantly lower for children with dyslexia than for control group in serial searching task with restricted time. Moreover, the searching accuracy in the serial searching task with restricted time was significantly correlated with the performance of the standardized written vocabulary test. These results showed that Chinese developmental dyslexia has deficits in perceptual processing and learning in serial searching process, suggesting that the deficits may underlie the development of Chinese reading skill to some extent.