Theory and evidence in cognitive neuropsychology: A "radical" response to Robertson, Knight, Rafal, and Shimamura (1993).

L. C. Robertson, R. T. Knight, R. Rafal, and A. P. Shimamura (1993) have presented a variety of arguments in opposition to a view of cognitive neuropsychological research put forth by so-called «radical» cognitive neuropsychologists. In this reply, I suggest that Robertson et al. (1993) failed to offer an effective response to «radical» criticisms of group-study methods, because the rationale they propose for patient-group studies rests on untenable assumptions. I further suggest that Robertson et al.'s (1993) objections to single-patient studies are without foundation and reflect an impoverished view of cognitive neuropsychology. Finally, I argue that single-patient studies are necessary in research aimed at exploring brain-cognition relationships as well as in research concerned with characterizing normal cognitive mechanisms