Mentalising and conversation-following in autism

Some people with autism spectrum disorders have been observed to experience difficulties with making correct inferences in conversations in social situations. However, the nature and origin of their problem is rarely investigated. This study used manipulations of video stimuli to investigate two questions. The first question was whether it is the number of people involved in social situations, that is, the source of problems in following conversations, or whether it is the increased mentalising demands required to comprehend interactions between several people. The second question asked was whether the nature and pattern of the errors that autism spectrum disorder participants show are the same as typically developing people make when they make an error. In total, 43 typically developed adults and 30 adults diagnosed with autism spectrum disorder were studied. We found that it was the amount of mentalising required, rather than the number of people involved, which caused problems for people with autism spectrum disorder in following conversations. Furthermore, the autism spectrum disorder participants showed a more heterogeneous pattern of errors, showing less agreement among themselves than the typically developed group as to which test items were hardest. So, fully understanding the observed behaviour consequent upon weakness in mentalising ability in people with autism spectrum disorders requires consideration of factors other than mentalising. People with autism spectrum disorders sometimes report difficulties with following observed conversations in social situations, especially those where several people are interacting with each other. But this has rarely been investigated directly. This study determines whether people with autism spectrum disorders do indeed have problems following observed conversations even when they perform well on IQ tests and investigates two possible reasons for any difficulty found: (1) some people may have a problem integrating stimuli from multiple speakers; (2) following a conversation between many people might make particularly high demands on mentalising abilities. We used a variety of video clips of people conversing together to investigate these two possibilities in 30 adults diagnosed with autism spectrum disorder and 43 age- and IQ-matched typical-developing adults. We found that it was the amount of mentalising required, rather than the number of people involved, which caused problems for people with autism spectrum disorder in following conversations. Furthermore, when the autism spectrum disorder participants made a mistake, the error they made was frequently not the same error that typically developed participants made, and the autism spectrum disorder population made a more varied set of errors than the typically developed participants. Together, these results suggest that people with autism spectrum disorders observe significant problems with following conversations between many people when they contain a lot of mentalising material, but where they do make a mistake, the conclusions they draw from the conversation they are observing may have a more complex cause than an impairment in mentalising alone.