Introduction

In chapter 9, it was shown that the use of neuropsychological group studies is not likely to lead to rapid advance in our understanding of normal function. Earlier, it was argued that, by contrast, the single-case study approach is an effective source of evidence. The argument was, however, a pragmatic one. The method leads to conclusions that are internally consistent and that mirror those arrived at by other means. Yet the theoretical structures used to interpret the different types of evidence may, as Rosenthal (1984) has pointed out, seem satisfactory as much for the ease and simplicity with which we can use them as for their empirical adequacy in modelling reality. If one examines the theoretical inferences made from single-case studies in earlier chapters, it becomes clear that they are delicately balanced on a set of implicit supporting assumptions. The inference procedures therefore need to be examined directly to assess whether they can bear the theoretical weight placed on them. In fact, those who have adopted the single-case approach have only rarely attempted to justify their leap from findings on a single patient to a general conclusion.

The most rigorous treatment of the inference procedure is that of Caramazza (1986).