He Yingchen, Legge Gordon E, Yu Deyue
Department of Psychology, University of Minnesota, Twin Cities, Minneapolis, MN, USA.
J Vis. 2013 Jun 24;13(7):14. doi: 10.1167/13.7.14.
Reading speed in normal peripheral vision is slow but can be increased through training on a letter-recognition task. The aim of the present study is to investigate the sensory and cognitive factors responsible for this improvement. The visual span is hypothesized to be a sensory bottleneck limiting reading speed. Three sensory factors-letter acuity, crowding, and mislocations (errors in the spatial order of letters)-may limit the size of the visual span. Reading speed is also influenced by cognitive factors including the utilization of information from sentence context. We conducted a perceptual training experiment to investigate the roles of these factors. Training consisted of four daily sessions of trigram letter-recognition trials at 10° in the lower visual field. Subjects' visual-span profiles and reading speeds were measured in pre- and posttests. Effects of the three sensory factors were isolated through a decomposition analysis of the visual span profiles. The impact of sentence context was indexed by context gain, the ratio of reading speeds for ordered and unordered text. Following training, visual spans increased in size by 5.4 bits of information transmitted, and reading speeds increased by 45%. Training induced a substantial reduction in the magnitude of crowding (4.8 bits) and a smaller reduction for mislocations (0.7 bits), but no change in letter acuity or context gain. These results indicate that the basis of the training-related improvement in reading speed is a large reduction in the interfering effect of crowding and a small reduction of mislocation errors.
正常周边视觉中的阅读速度较慢，但可以通过对字母识别任务的训练来提高。本研究的目的是调查促成这种提高的感觉和认知因素。视觉广度被假定为限制阅读速度的一个感觉瓶颈。三个感觉因素——字母敏锐度、拥挤效应和位置错误（字母空间顺序错误）——可能会限制视觉广度的大小。阅读速度还受到认知因素的影响，包括对句子上下文信息的利用。我们进行了一项知觉训练实验来研究这些因素的作用。训练包括每天在视野下方10°处进行四次三字母组识别试验。在训练前和训练后测试中测量了受试者的视觉广度轮廓和阅读速度。通过对视觉广度轮廓的分解分析，分离出了这三个感觉因素的影响。句子上下文的影响通过上下文增益来衡量，即有序文本和无序文本阅读速度的比率。训练后，视觉广度大小增加了5.4比特的信息传输量，阅读速度提高了45%。训练使拥挤效应的程度大幅降低（4.8比特），位置错误的程度降低较小（0.7比特），但字母敏锐度或上下文增益没有变化。这些结果表明，与训练相关的阅读速度提高的基础是拥挤干扰效应的大幅降低和位置错误的小幅减少。
