Appreciation of pragmatic interpretations of indirect commands: comparison of right and left hemisphere brain-damaged patients

Indirect commands can elicit "literal" interpretations, directly reflecting the content and form of the utterance, or "pragmatic" interpretations, incorporating knowledge of paralinguistic, social, or historical cues. The aim of this study was to demonstrate how right brain-damaged (RBD) subjects would perform on judgments of these forms of communication. It was predicted that relative to normal controls or aphasic subjects, the RBD subjects would have significant difficulty appreciating the pragmatic interpretation relative to the literal one. Subjects judged the appropriateness of two-part exchanges consisting of indirect commands, direct commands, Wh-questions coupled with pragmatic responses, literal responses, responses verifying the physical surround, or syntactically similar responses. The results confirm that the RBD subjects had a selective difficulty appreciating the indirect commands. Their preference of literal over pragmatic interpretations was significantly different to that of aphasics or normal controls. Hypotheses are offered to explain these data.