Case Studies in the Neuropsychology of Vision

Article excerpt

GLYN H. HUMPHREYS (Ed.)

Case Studies in the Neuropsychology of Vision Philadelphia PA: Psychology Press, 1999, 224 pages (ISBN 0-86377-895-X, us$49.95, Hardcover) Reviewed by PATRICIA A. MCMULLEN

Imagine a car speeding toward you or liquid pouring into a cup, which is seen as a series of stills that stop and restart every few seconds. How would you predict when the cup will overflow or when you and the car will collide? What if you successfully recognized many objects and words in the world, but not your own face in a mirror or those of family members? This edited volume contains investigations of individuals for whom impairments such as these are daily experiences due to cortical brain damage. Beyond the curiosity factor of these accounts lies the importance for theories about the organization of the normal visual cognitive system. Reciprocally, information about the normal system that is gained from these studies may guide future rehabilitation programs that are designed to help individuals pla ued bv these deficits.

Many unique and now classic cases are described in the nine chapters of this book. Deficits of early stages of vision such as those involved in the processing of motion and colour are described in the first two chapters by Charles Heywood, Josef Zihl, and Alan Cowey. Deficits of later stages of vision such as those involved in object recognition that result in visual agnosia are described by Glyn Humphreys, and Jules Davidoff and Elizabeth Warrington. Within this group of cognitive deficits are the fascinating category-specific agnosias in which recognition of one category of objects, usually those that are living, is selectively impaired while the recognition of artefactual objects is preserved. This topic is covered by Emer Forde, who has an upcoming book on the topic that is co-authored with Humphreys. Optic aphasia is another intriguing type of agnosia whereby an object cannot be recognized through the visual modality but motor actions that are appropriate to the object can be produced. Jane Riddoch discusses this problem in her chapter. Marlene Behrmann and her colleagues take on the issue of whether there are shared processes and representations in visual perception and imagery. Edward DeHaan and his colleagues describe covert recognition in prosopagnosia, another category-specific agnosia in which faces cannot be visually recognized. Finally, Martha Farah provides her broad theoretical perspective to the mix in the last chapter. Farah is one of the few researchers in this field who has taken on the task of summarizing many case studies and providing a theoretical framework for their interpretation.

I suggest that the title, Case Studies in the Neuropsychology of Vision, is somewhat misleading. It implies discussion of cases of all disorders of higher order vision due to brain damage, but acquired deficits of reading are not treated. As such, a more apt title might have been "Case Studies in the Neuropsychology of Object and Face Recognition." Psychology Press is producing a series of books on case studies in neuropsychology. To date, they have published Case Studies in the Neuropsychology of Memory, edited by Alan Parkin (1997), and Case Studies in the Neuropsychology of Reading, edited by Elaine Funnell (1999). …