Recent work investigating the biological and cognitive nature of autism is reviewed.
The hypothesis that autistic individuals suffer from a specific impairment in theory
of mind, and the relevance of this notion to the diagnosis of Asperger's syndrome,
is discussed. Theory of mind explanations of autism must account for the minority
of autistic subjects who pass false belief tasks. Two possible accounts are
considered; delay versus 'hacking'. A battery of theory of mind tasks was given
to able autistic subjects, and to mentally handicapped and young normal controls.
The results suggested the existence of subgroups: while some autistic subjects
performed inconsistently (perhaps using task-specific strategies), others performed
consistently well at first-order theory of mind tasks, and some passed an array of
second-order tasks.
Relevance theory suggests that understanding mental states is vital in
communication. Communication tasks were therefore given, to explore the theory
of mind abilities of the autistic subjects. Relevance theory predicted that subjects
unable to attribute mental states would show literal understanding, subjects with
first-order theory of mind would comprehend metaphor, but second-order theory of
mind would be necessary to understand irony. These predictions were tested and
confirmed with autistic subjects and normal children.
The theory of mind hypothesis cannot explain the persistent real-life handicaps of
autistics who understand mental states, nor account for the nonsocial peculiarities
seen in autism. A deficit in central coherence is suggested as the source of these
features. Results from a preliminary test of this hypothesis suggested that even
autistic subjects who develop theory of mind ability are impaired at extracting
context-dependent meaning.
The implications of these findings for the diagnosis of Asperger's syndrome, the
relations between the social and nonsocial impairments, and suggestions for further
research are discussed