Performer vs. observer: whose comfort level should we consider when examining the social acceptability of input modalities for head-worn display?

The popularity of head-worn displays (HWD) technologies such as Virtual Reality (VR) and Augmented Reality (AR) headsets is growing rapidly. To predict their commercial success, it is essential to understand the acceptability of these new technologies, along with new methods to interact with them. In this vein, the evaluation of social acceptability of interactions with these technologies has received significant attention, particularly from the performer's (i.e., user's) viewpoint. However, little work has considered social acceptability concerns from observers' (i.e., spectators') perspective. Although HWDs are designed to be personal devices, interacting with their interfaces are often quite noticeable, making them an ideal platform to contrast performer and observer perspectives on social acceptability. Through two studies, this paper contrasts performers' and observers' perspectives of social acceptability interactions with HWDs under different social contexts. Results indicate similarities as well as differences, in acceptability, and advocate for the importance of including both perspectives when exploring social acceptability of emerging technologies. We provide guidelines for understanding social acceptability specifically from the observers' perspective, thus complementing our current practices used for understanding the acceptability of interacting with these devices.