Conventional metaphor processing in autistic adults: a semantic priming experiment

Abstract In typical development, conventional metaphors are supposed to be stored as related senses within a single lexical entry, unlike homonyms, whose meanings are represented in separate entries. Autistic individuals often face challenges in understanding metaphors, raising the possibility that they process conventional metaphors more like homonyms—as unrelated meanings. In this study, we tested this hypothesis by comparing autistic and non-autistic adults on a lexical decision task involving both homonyms and conventional metaphors. We predicted that autistic participants would show inhibition effects (slower access) for both subordinate homonym meanings and metaphorical senses, while non-autistic participants would show inhibition only for homonyms. Our results partially confirmed these predictions. Non-autistic participants exhibited inhibition for both homonyms and conventional metaphors, suggesting that accessing metaphorical senses is more effortful than previously assumed. In autistic participants, metaphorical senses were even more difficult to access than subordinate homonym meanings and more difficult than for non-autistic participants. These findings indicate that autistic individuals experience particularly strong inhibition from the literal meaning when processing conventional metaphors, suggesting that these metaphorical senses may not be fully integrated as related senses in their mental lexicon.