Entering Your Space: How Agent Entrance Styles Shape Social Presence in AR

Embodied conversational agents (ECAs) capable of non-verbal behaviors have been developed to address the limitations of voice-only assistants, with research exploring their use in mixed and augmented reality (AR), suggesting they may soon interact with us more naturally in physical spaces. Traditionally, AI voice assistants are activated through wake-up keywords, and since they are invisible, their method of appearance has not been a concern. However, for ECAs in AR, the question of how they should enter the user's space when summoned remains underexplored. In this paper, we focused on the plausibility of ECAs' entering action into the user's field of view in AR. We analyzed its impact on user experience, concentrating on perceived social presence and co-presence of the agent. Three entrance styles were chosen for comparison: an obviously impossible one, a possible one, and an intermediate one, alongside a voice-only condition. We designed and conducted a within-subjects study with 38 participants. Our results indicated that while the plausibility of the action had less impact on functionality compared to the embodiment itself, it significantly affected social/co-presence. These findings highlight the importance of entrance design for future AR agent experiences.