Blowing in the wind: Increasing social presence with a virtual human via environmental airflow interaction in mixed reality

Abstract

In this paper, we describe two human-subject studies in which we explored and investigated the effects of subtle multimodal interaction on social presence with a virtual human (VH) in mixed reality (MR). In the studies, participants interacted with a VH, which was co-located with them across a table, with two different platforms: a projection based MR environment and an optical see-through head-mounted display (OST-HMD) based MR environment. While the two studies were not intended to be directly comparable, the second study with an OST-HMD was carefully designed based on the insights and lessons learned from the first projection-based study. For both studies, we compared two levels of gradually increased multimodal interaction: (i) virtual objects being affected by real airflow (e.g., as commonly experienced with fans during warm weather), and (ii) a VH showing awareness of this airflow. We hypothesized that our two levels of treatment would increase the sense of being together with the VH gradually, i.e., participants would report higher social presence with airflow influence than without it, and the social presence would be even higher when the VH showed awareness of the airflow. We observed an increased social presence in the second study when both physical–virtual interaction via airflow and VH awareness behaviors were present, but we observed no clear difference in participant-reported social presence with the VH in the first study. As the considered environmental factors are incidental to the direct interaction with the real human, i.e., they are not significant or necessary for the interaction task, they can provide a reasonably generalizable approach to increase social presence in HMD-based MR environments beyond the specific scenario and environment described here.