Deficits in object substitutions in autism: In search of an explanation

Background: The study on symbolic play in children with high-functioning autism (HFA) to be reported here builds on the results from an earlier study in which we found a specific, and not general, impairment in the symbolic or pretend play of young children with high functioning autism (HFA).

Objectives: The aim in this study was to explore whether either of two executive functioning hypotheses - the generativity and inhibition impairment hypotheses - can account for the difficulty children with autism have in engaging in object substitutions.

Methods: A group of 20 children with HFA and 20 typically developing (TD) children were matched on chronological age, verbal and overall mental age, performance IQ, full-scale IQ, and basic information processing speed. The groups were compared on their executive functioning abilities and symbolic play abilities, and the relationship between these abilities were also examined in order to explore the role of executive functions in their pretend play.

Results: The results, once again, indicated that the children with HFA displayed few symbolic play impairments relative to the TD children under both structured and unstructured conditions. However, they were specifically impaired in their ability to substitute objects in play. No significant group differences were found on the experimental measures of executive functioning, although parents reported inhibition difficulties amongst the children with autism. Although the results indicated that the executive functioning abilities of the children with HFA were associated with their symbolic play skills, the research findings did not support the generative or the inhibition impairment hypotheses.

Conclusions: While the results confirm our previous finding of a specific deficit in object substitution in autism, none of the current theoretical accounts of pretence can explain this finding.