Effects of In-Vehicle Voice Assistant Language Style on Trust and Usage Intention: The Moderating Role of Extraversion in Perceptual Pathways

As in-vehicle voice assistants (IVVAs) become increasingly important, their language design plays a crucial role in shaping user trust and acceptance. Grounded in the Cognition-Affect-Conation (CAC) framework, this study examines how language style influences perceptions and behavioral intentions through affective and anthropomorphic pathways, and how extraversion moderates these effects.A fixed-base driving simulator experiment compared formal-task and casual-social greetings. Results revealed that language style did not directly affect trust but significantly enhanced affective and anthropomorphic perceptions, which predicted usage intention. Trust was positively associated with usage intention and mediated perceptual effects. Anthropomorphic perception was positively associated with affective perception, supporting a layered process in early-stage IVVA interaction. Furthermore, extraversionstrengthened the perceptual effects of language style, especially amongextraverted users. These findings provide a CAC-guided account of IVVA interaction by suggesting a layered dual-path structure linking perceptual processes, trust, and usage intention, while informing socially responsive in-vehicle voice design.