From semantic concreteness to concretism in schizophrenia: An automated linguistic analysis of speech produced in figurative language interpretation

Lack of abstract thinking, known as <i>concretism</i>, is a well-known psychopathological feature of schizophrenia, reflecting the tendency to adhere to concrete aspects of stimuli and figurative language comprehension difficulties. Inspired by the similarity between 'concretism' as defined in psychopathology and 'concreteness' as defined in linguistics, namely a semantic dimension linked to perceptual experience, we tested the novel hypothesis that impairment in deriving figurative meanings is related to impairment at the semantic level, involving concreteness. We analysed speech samples from 63 individuals with schizophrenia and 47 controls, who were asked to verbalise the meaning of idioms, metaphors, and proverbs. By automatically extracting linguistic features from speech, we observed that answers in the schizophrenia group exhibited higher word concreteness and the related measure of word imageability, especially in proverbs, while not differing from controls' ones in lexical richness and speech-time composition. Concreteness in verbalisations produced by individuals with schizophrenia negatively predicted their ability to understand proverbs and their global pragmatic and cognitive profile. This study supports the idea that concretism is rooted in semantics, linking the tendency to concrete figurative interpretations and a bias towards concrete words. In this view, impairment in figurative language understanding can be seen as a difficulty in abstracting away from perceptual-related properties associated with linguistic inputs, in the broader context of multisensory integration disruption. The study discloses new areas of interest for the automated analysis of speech in psychosis, pointing to the importance of considering concreteness for better characterising linguistic profiles and identifying clinically relevant linguistic dimensions.