Action Units: Directing User Attention in 360-degree Video based VR

A key challenge to effective storytelling using Virtual Reality (VR), such as with 360-degree videos, is how to direct user attention to important content without taking away user agency for free exploration. In this paper, we introduce the notion of an Action Unit system, composed of social cues such as head and arm movements, as a way of directing users to focus on content important for the given narrative. We applied this idea to a 360-degree VR tour, and evaluated its effects on memory, engagement, enjoyment, and cyber-sickness. The results indicate that the levels of engagement and enjoyment increased when these Action Units were applied. Users also preferred the Action Units for their diegetic aspects.