Relations between verb factivity and first-order and second-order false belief understanding: Evidence from Mandarin-speaking typically developing children and children with autism spectrum disorders.

Previous studies have shown that factivity is closely related to first-order false belief (FB). However, whether the role of factivity in first-order FB extends to second-order FB remains unclear. Investigations of verb factivity and second-order FB would contribute to our knowledge of the role of language in theory of mind (ToM) development. This study examined relations between verb factivity and first-order and second-order FB reasoning in 156 four- to seven-year-old typically developing (TD) Mandarin-speaking children, and in 17 children with autism spectrum disorders (ASD) and 17 TD matched controls. Children's understanding of a factive 'know', a non-factive 'think' and a counter-factive 'pretend' was assessed by a truth value judgement task. For TD children, 'know' (factive) significantly predicted their first-order and second-order FB performances, and 'pretend' (counter-factive) significantly predicted their first-order FB performance. For autistic children, they performed significantly poorer than their TD counterparts on complementation, verb factivity, first-order and second-order FB, and their first-order FB performance was significantly related to 'pretend' (counter-factive). The findings suggest that verb factivity relates to both first-order and second-order FB, and verbs differing in factuality and mental state status contribute differently to ToM development.