Nazir T A, Jacobs A M, O'Regan J K
Center for Research in Cognitive Neuroscience (CNRS-CRNC), Marseille, France.
Mem Cognit. 1998 Jul;26(4):810-21. doi: 10.3758/bf03211400.
Word recognition performance varies systematically as a function of where the eyes fixate in the word. Performance is maximal with the eye slightly left of the center of the word and decreases drastically to both sides of this optimal viewing position. While manipulations of lexical factors have only marginal effects on this phenomenon, previous studies have pointed to a relation between the viewing position effect (VPE) and letter legibility: When letter legibility drops, the VPE becomes more exaggerated. To further investigate this phenomenon, we improved letter legibility by magnifying letter size in a way that was proportional to the distance from fixation (e.g., TABLE). Contrary to what would be expected if the VPE were due to limits of acuity, improving the legibility of letters has only a restricted influence on performance. In particular, for long words, a strong VPE remains even when letter legibility is equalized across eccentricities. The failure to neutralize the VPE is interpreted in terms of perceptual learning: Since normally, because of acuity limitations, the only information available in parafoveal vision concerns low-resolution features of letters; even when magnification provides better information, readers are unable to make use of it.
单词识别表现会随着眼睛在单词中的注视位置而系统地变化。当眼睛位于单词中心略偏左的位置时，表现最佳，而从这个最佳注视位置向两侧移动时，表现会急剧下降。虽然词汇因素的操作对这一现象只有微小影响，但先前的研究指出了注视位置效应（VPE）与字母清晰度之间的关系：当字母清晰度下降时，VPE会变得更加明显。为了进一步研究这一现象，我们通过以与注视距离成比例的方式放大字母大小来提高字母清晰度（例如，TABLE）。与如果VPE是由于敏锐度限制所预期的情况相反，提高字母清晰度对表现的影响有限。特别是对于长单词，即使在不同偏心度下字母清晰度相等时，强烈的VPE仍然存在。无法消除VPE这一现象可从知觉学习的角度来解释：因为通常由于敏锐度限制，在副中央凹视觉中可用的唯一信息涉及字母的低分辨率特征；即使放大提供了更好的信息，读者也无法利用它。
