We aim to identify the mechanisms underlying autistic children’s language difficulties by evaluating three competing accounts: (1) autistic children experience language difficulties primarily due to challenges in social engagement, with limited benefit from both social and non-social language input; (2) autistic children have deficits in the core language learning mechanisms irrespective of input type; and (3) autistic children possess intact learning mechanisms, but social input hinders their learning, while non-social input facilitates it. To test these accounts, we examined immediate syntactic learning—the tendency to reuse recently encountered sentence structures—and cumulative syntactic learning—the long-term reuse of structures after repeated exposure. Autistic and typically developing (TD) children, matched on language ability and non-verbal IQ, were exposed to syntactic structures via a live human speaker, computer, or a mix of both across two sessions one week apart. Both groups showed equivalent immediate learning across all exposure conditions. However, cumulative learning revealed striking group differences. Autistic children showed cumulative learning only in the computer condition, while TD children did in all conditions except the computer. Our findings demonstrate that autistic children are capable of both immediate and cumulative syntactic learning, but their cumulative learning is hindered by social exposure and facilitated by non-social exposure. In line with the third account, these results suggest that autistic children possess intact learning mechanisms, but the effectiveness of their learning is modulated by contextual factors in ways that differ from TD children.
Hwang et al. (Tue,) studied this question.