Investigating Remote Tactile Feedback for Mid-Air Text-Entry in Virtual Reality

In this paper, we investigate the utility of remote tactile feedback for freehand text-entry on a mid-air Qwerty keyboard in VR. To that end, we use insights from prior work to design a virtual keyboard along with different forms of tactile feedback, both spatial and non-spatial, for fingers and for wrists. We report on a multi-session text-entry study with 24 participants where we investigated four vibrotactile feedback conditions: on-fingers, on-wrist spatialized, on-wrist non-spatialized, and audio-visual only. We use micro-metrics analyses and participant interviews to analyze the mechanisms underpinning the observed performance and user experience. The results show comparable performance across feedback types. However, participants overwhelmingly prefer the tactile feedback conditions and rate on-fingers feedback as significantly lower in mental demand, frustration, and effort. Results also show that spatialization of vibrotactile feedback on the wrist as a way to provide finger-specific feedback is comparable in performance and preference to a single vibration location. The micro-metrics analyses suggest that users compensated for the lack of tactile feedback with higher visual and cognitive attention, which ensured similar performance but higher user effort.