Mentalization as a mechanism for constructing meaning under ambiguity

Pseudowords lack conventional lexical meanings, but growing evidence suggests that they can nevertheless elicit structured (semantic) interpretations. The present study (N = 103) tested whether individual differences in mentalization are related to how people construct meanings for novel verbal stimuli. Participants generated definitions for real words and pseudowords and completed three mentalization-related measures: the Interpersonal Reactivity Index (IRI), the Reading the Mind in the Eyes Test (RMET), and the Triangles task. Using representational similarity analysis (RSA), we examined whether participants who were similar in mentalization-related profiles were also similar in their definition profiles. IRI and RMET response-profile similarity showed no evidence of an association with definition similarity, while similarity in open-ended descriptions of Triangles Theory-of-Mind animations predicted similarity in pseudoword definitions, but not real-word definitions. This association remained significant after controlling for similarity in Triangles control Action-clip descriptions, suggesting that it was not reducible to shared verbal-response format or general description style. Additional reconstruction analyses showed that pseudoword-definition embeddings can partially recover the participant-level representational geometry of Theory-of-Mind descriptions. These findings suggest that novel meaning construction is not only a lexical-semantic process but is also aligned with broader interpretive tendencies involved in assigning coherent social meaning to ambiguous experience, with implications for understanding the links between semantic cognition, mentalization, and developmental word learning.