Theory of mind, general language competence and complementation in children with and without autism spectrum disorder : a systematic review and meta-analysis

Abstract

Objective: This paper evaluated the strength of evidence for correlation between theory of mind (ToM), complementation and general language for typically developing (TD) children and children with autism spectrum disorders (ASD). The moderating effect of general language on the correlation between complementation and ToM was also explored. Methods: The study protocol was registered on Open Science Framework. Thirteen databases were searched to identify cross-sectional studies that targeted TD or ASD children aged below 12;0. Included studies were appraised using the Joanna Briggs Institute Critical Appraisal Tool. Pooled effect sizes were synthesized qualitatively. Meta-analyses were performed with group and receptive language as moderators. Results: Twenty-four studies with nineteen TD and six ASD groups were included. The quality of included studies were adequate for cross-study comparison. Moderate correlations were found for both general language and complementation with verbal ToM but not with non-verbal ToM. There was a trend that ASD individuals had a stronger correlation between general language and verbal ToM than that of TD individuals but such trend was not observed for complementation. Receptive language ability was a significant moderator of correlation between verbal ToM and complementation (communication verbs), thus suggesting the mastery of complementation structure has specific effect on one’s ToM development when general language is considered. Conclusion: Preliminary evidence suggested that for both TD and ASD populations, the mastery of complementation might not have significant effect on verbal ToM when general language ability is considered. More studies with ASD groups are needed to provide direct evidence to support this claim.