Comprehension of indirect requests in adults with autistic disorders and mental retardation.

Eight adults with autistic disorders and 8 IQ-matched, mentally retarded (MR) subjects were given a task involving the comprehension of indirect requests. In one condition, requests were prefaced by instructions making their illocutionary force clear (I'm going to tell you to color some circles). In a second condition, the same requests were presented in an unstructured conversation. Although the performance of the MR subjects was better in both conditions, both groups performed similarly to normal 4- to 6-year-olds. In the unstructured condition, however, the autistic group's performance was significantly depressed, especially on sentences requiring greater semantic processing. The implications of these findings for understanding language and social deficits in autistic and similar individuals are discussed.