Activation of Thematic and Taxonomic Relations During Lexical-Semantic Processing in Autistic Children: Evidence From Eye Movements

This study investigated the activation of thematic and taxonomic relations during online lexical-semantic processing in autistic children using an eye-tracking competition task. Thirty-six preschool-aged autistic children and 35 age-, gender-, and verbal-IQ-matched neurotypical (NT) children viewed arrays containing a target object, a thematically related competitor, a taxonomically related competitor, and an unrelated distractor while hearing the target word. Results revealed three key findings. First, both groups demonstrated activation of thematic and taxonomic relations during lexical processing, with comparable timing of activation onset. Second, while autistic children began to systematically orient attention to the target as quickly as NT children, they showed reduced overall attention to the target during lexical processing. Third, autistic children exhibited stronger activation of taxonomic relations and stronger taxonomic competition effects on target recognition compared to NT children, whereas their activation of thematic relations and thematic competition effects were comparable to NT children. These findings suggest that while the basic thematic and taxonomic activation processes remain robust in autistic children, and while their initial activation of the target and semantically related representations is as fast as that of NT children, the increased sensitivity to taxonomic relations in autistic children might interfere with the overall processing efficiency of target words. These results advance our understanding of lexical-semantic organization and processing in autism and provide implications for language intervention strategies.