Visual Representation of Object Location: Insights From Localization Impairments

Abstract

aged or fail to develop normally, the most basic and seemingly triv ial aspects of visual perception may be impaired drastically. Care ful analysis of the impairments not only makes apparent the intricacy of visual mechanisms, but also of fers insights into the structure and functioning of these mechanisms. For several years, we and our colleagues have been studying A.H., a young woman with an im pairment in localizing objects from vision.1 A.H., who recently grad uated with honors from a major university, has normal visual acu ity. Her visual fields are also nor mal (i.e., she can see, with each eye, a normal-sized region of space). Her medical history is un remarkable, and no abnormalities were apparent on clinical neuro logical exam, electroencephalo gram, or magnetic resonance im aging. Throughout her schooling, A.H. has experienced difficulty with spelling, math, and foreign languages, but has never been placed in classes for students with learning disabilities. A.H. showed severe and dra