Theory of mind: Effects of ecological syntactic training in children with and without autism

Complement clauses, such as Mary says that Santa exists , are complex linguistic structures that have been argued to help children grasp others’ beliefs when those beliefs do not align with reality. This study investigates whether using children's books containing false-complement clauses can improve false-belief reasoning in children with autism spectrum disorder (ASD) and typically developing (TD) children. The question is whether structured dialogic reading at home, led by parents, improves children's understanding of complex syntax and also false beliefs. The study involved 26 native French-speaking children, 14 with TD and 12 with ASD, aged between 34 and 121 months. Screening ensured that they had not mastered complement clauses or false-belief reasoning. The children's parents participated in a dyadic reading program over 8 weeks, with specially designed books targeting either complement or relative clause structures. A cross-over design was used so that all children were read both of the books but in two orders. Children were tested before, at the change-over point, and after all the training. It was hypothesized that improvement in false-belief tasks would occur only after exposure to the book containing false-complement clauses. Results showed that both ASD and TD children showed significant progress in false-belief tasks after reading the target book, but no improvement after reading the control book. Importantly, this improvement was consistent regardless of the child's clinical status. The relative clause training did not produce similar effects, indicating a specific advantage of complement training for theory of mind development. Statistical analyses confirmed these findings, with significant improvements seen in false complements ( P < 0.001) and false beliefs ( P < 0.01) across the intervention. In conclusion, the findings align with previous studies that suggest false-complement training boosts performance in false-belief tasks, and highlight the benefits of parent-led, home-based, ecological training of language.