Modality and Theory of Mind: Perspectives from Language Development and Autism

It is widely assumed in the developmental literature that certain classes of modal expression appear later in language acquisition than others; specifically, epistemic interpretations lag behind non-epistemic (or root) interpretations. An explanation for these findings is proposed in terms of the child’s developing theory of mind, i.e. the ability to attribute to oneself and others mental representations, and to reason inferentially about them. It is hypothesized that epistemic modality crucially implicates theory-of-mind abilities and is therefore expected to depend on prior developments in the child's ability to handle representations of mental representations. In support of this hypothesis, it is shown that autistic individuals (who arguably possess a deficient theory-of-mind mechanism) have difficulty with epistemics.