Developmental dyslexia and potential deficits of experience-driven visual processing

[摘要] Previous research suggests that dyslexic readers can have subtle problems with recognizing familiar non-word objects such as faces. Such deficits have not always been observed, however, and the potential roots of the problem are unclear. In two experiments, we sought to firmly establish the existence and specificity of this problem. We administered a perceptual face matching task (with minimal memory requirements) to participants with and without a history of reading problems (total N=105). As the task required the discrimination and matching of previously unknown faces across viewpoint, rendered with identical texture, participants were forced to rely on fine-grained visual discrimination of high-level shape cues. Face matching performance on this task was found to predict reading problems, both in a general sample of university students (experiment 1) as well as in a sample of matched dyslexic and typical readers (experiment 2). Difficulties with face matching were consistently found to predict dyslexia over and above that of matching novel objects (YUFOs), matching noise patterns that shared low-level visual properties with faces (scrambled faces), and classifying stimuli as belonging to a face (face/no face). The relationship between dyslexia and face matching problems also was not accounted for by measures of ADHD (typically comorbid with dyslexia). Our results show that people with dyslexia do not have general visual problems, not even general problems with objects, or faces. Instead, their problems could be mainly restricted to individuating visually homogeneous objects, such as faces and words, with which people have had prior experience.

[学科分类] 眼科学