Shifting contexts, shifting concreteness: Discourse patterns in individuals with schizophrenia

Concreteness, the degree to which words evoke perceptible and tangible referents, is central to conceptual abstraction and thought organisation. Individuals with schizophrenia often exhibit a bias toward concrete interpretations also known as concretism. However, most existing evidence derives from proverb-interpretation tasks, which capture only a narrow range of linguistic behaviour. The present study analyzed a corpus of discourse produced by individuals with schizophrenia and healthy controls to examine whether concreteness varies across different communicative contexts, reflecting the distinct cognitive demands of each discourse mode. The corpus included speech samples from 70 participants with schizophrenia and 48 healthy controls who had previously completed three tasks: Autobiographical Narration (AN), Picture Description (PD), and cartoon-based Story Narration (SN). Contextual concreteness was estimated for noun occurrences using a prediction model initially trained on AI-generated Spanish ratings and subsequently fine-tuned with human context-dependent ratings. Results revealed decisive evidence that lexical concreteness varied across discourse tasks. The omnibus analysis did not support either a global group effect or a Group × Task interaction. Nevertheless, planned task-specific comparisons showed higher concreteness in the schizophrenia group during Story Narration, with strong evidence under the directional analysis and moderate evidence under a two-sided sensitivity analysis. Evidence was inconclusive for Picture Description and favoured the null hypothesis for Autobiographical Narration. This pattern is consistent with the possibility that concreteness differences in schizophrenia are more detectable in some discourse contexts than in others. However, because the Task × Group interaction was not supported, the results do not establish that the magnitude of the group difference varies reliably across tasks.