We investigated what strategies underlie figurative language processing in two groups of participants distinguished by the presence of a developmental deficit, highly-verbal participants with autism, and control participants without autism in two age ranges each. Individuals with autism spectrum disorder are characterised by impaired social interaction and communication. Even at the high end of the spectrum, where structural language is adequate, difficulties in comprehending non-literal aspects of language are widely attested. The exact causes of these problems are, however, still open to debate. In an interactive sentence-picture matching task participants selected the most suitable image representation of a non-literal figurative expression that matched the target meaning, while their eye-movements and hand movements were being tracked. Our results suggest that individuals with ASD have different processing patterns than typically developing peers when interpreting figurative language, even when they provide the correct answers. Both children with and without autism, and participants with autism display greater uncertainty and competition between alternatives when providing the answer, often reflected in also considering the literal interpretation of the expression against its target figurative meaning. We provide evidence that expression transparency and decomposability play a central role in figurative language processing across all groups.
Keywords: Language processing; autism; eye tracking; figurative language; mouse tracking.