Blindsight : A Case Study and Implications

Studies of patients blind from damage to the neocortex have revealed that some can discriminate certain visual events within their 'blind' fields. They are not aware that they can do so, however - they think that they are only guessing. This book is an account of research into a particular case of this 'blindsight' phenomenon. It also discusses the historical and neurological background, and reviews other cases and issues. - ;Damage to a particular area of the brain - the neocortex - is generally understood to result in blindness. Studies of some patients suffering from this form of blindness have nevertheless revealed that they can discriminate certain types of visual events within their 'blind' fields. They are not aware that they can do so, however - they think that they are only guessing. This phenomenon has been termed 'blindsight'. The present book gives an account of research over a number of years into a particular case of blindsight, together with a discussion of the historical and neurological background, a review of cases reported by other investigators, and a number of theoretical and practical issues and implications. - ;PART I: Background; D.B.: Clinical history and early testing; PART II: Reaching for randomly located targets; 'Presence' versus 'absence'; Visual acuity; Movement thresholds; Discrimination of orientation; 'Form' discrimination; Detection with slow rate of onset; The natural blind-spot (optic disc) within the scotoma; Left versus right eye; Detection of direction of contrast; 'Waves'; Matching between impaired and intact fields; Matching within the impaired field; Double dissociations between form and detection; Standard situation; PART III: Review of other cases; Status, issues, and implications; References; Indexes. -