Constraints on the processing of indirect speech acts: evidence from aphasiology.

The ability of anterior aphasics and patients with right-hemisphere damage to comprehend both the literal and nonliteral readings of indirect speech acts was examined. Subjects viewed videotaped episodes in which one actor asked another "Can you X?" and the second actor responded with either an action or a simple "Yes." Subjects judged whether the response was appropriate given its context. Anterior aphasics could comprehend the nonliteral but not the literal reading, supporting models that posit that people have direct access to nonliteral but conventional readings. Patients with right-hemisphere damage could appreciate the direct reading, but failed to distinguish between appropriate and inappropriate action-responses. This finding suggests that it may be possible to dissociate the pragmatic and syntactic aspects of comprehension of indirect speech acts.