ABSTRACT
The claim that we can gain important insights into the normal cognitive system from investigations of the impairments that can follow brain injury would be endorsed by virtually all contemporary neuropsychologists. Underlying the recent upsurge of interest in cognitive neuropsychology, however, is the belief that it is by comparing the precise nature of the different impairments from which carefully selected patients suffer that most progress will be made in advancing our understanding of the way in which the cognitive system is organized (Ellis and Young 1988; Shallice 1988). Consequently, influential theories in contemporary cognitive psychology in areas such as reading (Coltheart 1985), working memory (Baddeley 1992) and face processing (Young and Bruce 1991) are as strongly supported by findings from individual case studies of clinical patients as they are by experiments examining the performance of normal subjects under laboratory conditions.
