J. Mark Williams 
Cognitive Approaches to Neuropsychology [PDF ebook] 

Since its early development, neuropsychology has examined the manner in which cognitive abilities are mediated by the brain. fudeed, all of neuropsy- chology, and especially clinical neuropsychology, could be subsumed under this general investigation. However, a variety of factors impeded the close as- sociation of neuropsychologists and cognitive/experimental psychologists. These factors were prominent influences in both camps, which kept the study of cognition away from a consideration of biological foundations and kept neuropsychology theoretically impoverished. In recent years, these factors have diminished and "cognitive neuropsychology" has become a popular term to describe the new movements to join the study of cognition with the study of brain function. The factors which kept these areas separate were manifestations of his- torical trends and represent a social distance which largely happened by acci- dent. The first and perhaps most important factor was that early investigators of cognition and brain function were not psychologists. Most were neurolo- gists or otlier neuroscientists who were excellent observers of behavior fol- lowing brain injury but had virtually no theoretical context of cognitive psy- chology, which would allow them to expand and deepen their understanding of the behavior they were observing. As more psychologists who have such a context have observed the consequences of brain disorders, especially aphasia and amnesia, the study of them has become far more comprehensive as theo- ries of language and memory derived from cognitive psychology have been incorporated into the investigations.