Too much or too little? Vocal accommodation and social evaluation of voice-based assistants in relational roles

Abstract Voice-based assistants (VBAs) increasingly function in relational roles such as tutoring, medical guidance, and customer service, prompting users to evaluate them as communicative partners. Drawing on Communication Accommodation Theory and the Stereotype Content Model, this study examines how vocal accommodation style shapes social evaluations of VBAs. A 2 (accommodation style: overaccommodative vs. underaccommodative) × 3 (relational role: tutoring, medical advice, customer service) between-subjects experiment was conducted with 284 U.S. adults recruited via Prolific. Participants listened to an audio vignette featuring a VBA and evaluated the agent and its communication. Results revealed strong main effects of accommodation style: overaccommodative VBAs were perceived as warmer, more competent, and more appropriately accommodative, and were evaluated more positively as communicators and speakers than underaccommodative VBAs. Relational context did not moderate these effects, except for modest variation in communication quality evaluations. These findings extend accommodation research into the auditory domain and highlight the asymmetric social costs of underaccommodation across tutoring, medical, and customer service contexts, with overaccommodation functioning as a comparatively lower-risk communicative strategy for voice-based agents.