Evidence of spontaneous mentalizing in children with Cornelia de Lange and fragile X syndromes, but not autistic children.

It has been suggested that mentalizing abilities underlie the distinct profiles of autism characteristics observed between Cornelia de Lange (CdLS) and fragile X syndromes (FXS) and autistic people without a genetic syndrome. However, traditional explicit mentalizing tasks have high language demands that may mask true mentalizing abilities in these populations. We compared performance on traditional explicit tasks and an implicit anticipatory looking mentalizing task in children with CdLS (N = 9), boys with FXS (N = 9), autistic (N = 22) and neurotypical (N = 34) children. The groups showed divergent patterns of performance. Neurotypical children had higher explicit mentalizing scores than all other groups. However, neurotypical, FXS and CdLS groups showed better implicit mentalizing performance than autistic children. Both chronological age and receptive language ability correlated with explicit mentalizing scores in neurotypical children. In autistic children, there was an association between explicit mentalizing score and receptive language ability but not chronological age. Explicit mentalizing score was not associated with receptive language ability or chronological age in the CdLS and FXS groups. Neither chronological age nor receptive language ability correlated with implicit mentalizing task performance in any group. Findings suggest that explicit tasks may mask true mentalizing abilities in autistic children, children with CdLS and children with FXS.