Atypical information processing in children with autism: links with inner speech deficit

[Truncted abstract] A number of studies have provided evidence that individuals with autism have poor semantic processing of verbal information, instead gaining greater meaning from pictorial information. The aims of this thesis were, to firstly, investigate the verbal and pictorial encoding abilities of children with autism, and secondly, to determine the extent to which limitations in the use of inner speech may drive any encoding differences. The first study investigated the notion that children with autism have an atypical verbal processing style, showing poor semantic but enhanced phonological encoding of verbal stimuli. The experiment compared the performance of children with autism and ability-matched controls (N = 20 in each group) on a novel explicit verbal recall task that contained 20 word stimuli. Recall performance could be benefited through, in one condition, an understanding of the semantic links between the stimuli, and in another condition, an understanding of the phonological similarities between the stimuli. The design of the recall task controlled for the possibility that children with autism have poor retrieval strategies (by providing either a semantic or phonological retrieval cue) and hence maximized the likelihood that any between-groups differences in performance would be related to problems at the encoding stage. There was no difference between the two groups. Follow up comparisons revealed that the performance of the autism group was consistent with that of typically developing children of the same chronological age. The idea that individuals with autism have increased facility for processing pictorial information (Kamio & Toichi, 2000) was then investigated.