Making beds and dying of boredom literally: A developmental study on the comprehension of nonliteral uses of language in autism

Comprehension of simple nonliteral uses of language was investigated in three- to nine-year-old autistic and linguistically matched typically developing (TD) children, by assessing their understanding of nonliteral uses of language with potential literal senses. Children were tested on conventional metaphors, idioms, hyperboles, and light verb constructions. The aim of the study was to determine whether autistic children showed a genuinely strong tendency to interpret nonliteral uses of language literally across development. A total of 166 children (N = 42 Autistic children; N= 124 TD children) were tested using a paradigm with online (response times) and offline (picture selection) measures. Overall, there were no significant group differences on the picture selection task, but autistic children were slower in spite of increasing verbal age. Both groups showed continuous improvement of their understanding of literal and nonliteral senses with increasing verbal mental age. The results, nevertheless, call for a reflection on the (possible) literalist behavior in autism, indicating that it is important to take into account individual variation, as we observed different kinds of performance within the autistic group.