Non-Specificity of Theory of Mind in Children with and without Autism Spectrum Disorder (ASD): Evidence From a New Non-Verbal False Sign Task

Background: It is well-known that children with Autism Spectrum Disorder (ASD) have problems with understanding mental states, especially false beliefs. However, a standard false belief task involves mentalising as well as representational understanding. If children with ASD have a general difficulty in understanding representations, this challenges the view that mentalising is a domain-specific problem in ASD.

Objectives: The current study tested whether children with and without ASD’s difficulty on false beliefs may be explained as a problem in understanding representations rather than mental states specifically.

Methods: A new non-verbal false sign task (Iao, 2011), was modeled on the non-verbal false belief and false photograph tasks devised by Apperly et al. (2004, 2007) which used a minimum level of language, eliminated the requirement of inhibiting one’s knowledge about reality, and controlled for incidental executive demands. 18 children with ASD and 18 children without ASD (verbal mental age and non-verbal intelligence quotient matched) were tested on these non-verbal false sign (FS), false belief (FB) and false photograph (FP) tasks.

Results: Performance of children with ASD was significantly worse than that of children without ASD on the FB and FS tasks, but not on the FP task. When performance on the FP task or verbal mental age was controlled, the correlation between the FB and FS tasks remain significant for both children with and without ASD.

Conclusions: This equivalence found between the FB and FS tasks in children with and without ASD suggests that their difficulty on false beliefs may be explained as a general cognitive difficulty in understanding representations. This finding provides further support for the non-specificity claim of Theory of Mind. However, whether impaired representational understanding causes mentalising impairments or vice versa has not yet been established.