字符识别是人类最重要的日常活动，也是脑与认知科学研究的重要领域之一。我们在此领域的长期目标是运用严格的心理物理学方法，系统、全面地了解中国人正常视力和低视力人群汉字识别以及具有普遍意义的字符识别的视觉心理物理学特征，为临床诊断、教育评价、工业设计等方面提供参考。本项目拟在申请人已有工作的基础上，对字符识别的视觉拥挤效应的心理物理学机制做进一步的研究，内容包括：1）运用我们实验室擅长的知觉学习方法比较视觉拥挤效应的错误特征整合和低注意分辨率两类理论；2）研究视觉拥挤效应知觉学习中的刺激身份错误和位置错误变化；3）结合实验和建模对不同的拥挤效应机制进行量化比较; 4）研究视觉拥挤的分组效应对中文阅读的影响；5）在应用方面，研究视觉拥挤效应在中文阅读儿童及阅读障碍儿童中的表现，以及通过知觉训练改善拥挤效应的可能性。

Letter recognition is one of the most important human daily acticivities, and the research on this topic is one of the important areas of brain and cognitive sciences. Our long-term goal is to study letter and Chinese character recognition in normal and low vision population using strict psychophysical measurements, so as to provide guidance for clinical diagnosis and inhabitation, educational evaluation, and industrial design. On the basis of our previous work, the proposed research will focus on the psychophysical mechanisms of visual crowding in Chinese character and letter recognition. Specifically, the proposal consists of 1) the comparison of feature integration theory and attention resolution theory of visual crowding using perceptual learning methods; 2)the change of crowding identity and position errors with perceptual learning; 3) a quantitative comparison among various crowding mechanisms with experimental and modeling methods; 4) the impact of the grouping effects on crowding on Chinese reading; 5) visual crowding in Chinese reading children, escepially in those with developmental dyslexia, and perceptual learning training to reduce crowding and improve reading.