汉字知觉专家化的行为和脑机制发展:儿童和文盲研究

Perceptual expertise is important for visual information processing. Perceptual expertise exhibits holistic processing and left-side bias effects, and N170 component as an electrophysiological maker for processing objects of expertise. Recently, many studies focused on the cognitive and neural mechanisms of word perceptual expertise. However, the developmental trajectories of word perceptual expertise are still unclear. Perceptual expertise as a long-term perceptual learning mechanism, it’s necessary to explore the time trajectory to reveal the cognitive and neural mechanisms. In order to clarify how do different areas of perceptual expertise share or compete the same neural resources during the development, it’s necessary to investigate the development of word and face perceptual expertise together during elementary school stage. Interestingly, how the word experience influences on expertise development is an unsolved problem in the field. So, the primary school children and adult illiterates are important participants to explore the scientific issues.. In our project, we will use behavioral and EEG technology. And we also used three aspects of empirical research，including developmental, intervention and neuroimaging studies, to indicate the cognitive and neural mechanisms of Chinese character perceptual expertise. 1) We will investigate the developmental trajectory of neural mechanism involved in processing Chinese characters with children as participants. 2) We will investigate the relations between Chinese characters and faces. 3) In order to reveal the flexibility and plasticity of neural mechanism, we investigate the development of behavioral and brain mechanisms of Chinese character perceptual expertise during the illiterates learning Chinese characters. The results are important to understand the neural mechanism and plasticity of perceptual expertise, and they are also important to optimize the learning style of Chinese characters.

知觉专家化是大脑加工视觉信息的重要机制。字词知觉专家化的认知和脑机制是相关领域的热点，但是其发生、发展轨迹还不清楚。知觉专家化作为一种长时程的知觉学习机制，要揭示其背后的认知和神经机制，就必须考察其发展的时间轨迹。另外，字词经验对专家化发展的影响是此领域一个重要的未解问题。对具有不同汉字经验的小学儿童，以及成人文盲和非文盲进行研究是解决此科学问题的重要途径。本项目采用行为和脑电技术，拟通过发展、干预和神经影像三个方面的实证研究揭示知觉专家化的认知和神经机制：1) 儿童学习过程中汉字知觉专家化的发展时间轨迹及其脑机制。2) 汉字知觉专家化与人脸知觉专家化的关系。3)对成年文盲进行汉字学习干预，揭示汉字知觉专家化神经基础的灵活性和可塑性。相关研究结果对于理解知觉专家化的神经机制及脑的可塑性有重要理论价值，而且对于优化汉字教学有重要实践参考价值。

知觉专家化是大脑加工视觉信息的重要机制。字词知觉专家化的发生、发展轨迹还不清楚。知觉专家化作为一种长时程的知觉学习机制，要揭示其背后的认知和神经机制，就必须考察其发展的时间轨迹。另外，字词经验对专家化发展的影响是此领域一个重要的未解问题。对具有不同汉字经验的小学儿童，以及成人文盲和非文盲进行研究是解决此科学问题的重要途径。. 本课题采用行为和脑电技术，通过发展、干预和神经影像三个方面的实证研究揭示知觉专家化的认知和神经机制：1)儿童学习过程中汉字知觉专家化的发展时间轨迹及其脑机制。2)汉字知觉专家化与人脸知觉专家化的关系。3)对成年文盲进行汉字学习干预，揭示汉字知觉专家化神经基础的灵活性和可塑性。. 经过四年的研究，获得许多重要研究成果：. （1）汉字倒置效应经过一年正规学校学习就能形成，而到三年级才与成人大致相似；儿童小学五六年级的汉字组合效应都与成人存在差异；儿童汉字左侧偏爱效应在一年级还没有出现，到三年级与成人类似；儿童小学一年级学习大量汉字能促进汉字知觉专家化的发展，但是这种优势随年龄增大而减弱甚至消失;. （2）小学一年级就能在N170成分上区分汉字与线条图，表现出字词加工的专家化特性，到小学六年级才能在N170成分上对真字和伪字进行区分，表现出N170对正字法精细加工的特异性;. （3）汉字知觉专家化与面孔知觉专家化相互影响。首先，采用适应范式研究表明汉字N170成分的功能是面孔N170功能的一部分；第二，文字学习对面孔加工具有重要影响。繁体汉字学习和简体汉字学习对面孔加工的发展具有影响；没有学习汉字的文盲的面孔加工能力比非文盲要弱；汉语阅读困难儿童的汉字和面孔整体加工能力都弱于同年龄段儿童;. （4）成人文盲经过半年汉字学习表现出N170成分的汉字整体加工特异性。. 本研究结果对于理解知觉专家化的神经机制及脑的可塑性有重要理论价值，而且对于优化汉字教学有重要实践参考价值，已经用于指导深圳和衢州等地的小学汉字教学中。