MusiKeys: Exploring Auditory-Physical Feedback Replacement for Mid-Air Text-Entry

Extended reality (XR) technology is positioned to become more ubiquitous in life and the workplace in the coming decades, but the problem of how to best perform precision text-entry in XR remains unsolved. Physical QWERTY keyboards are the current standard for these kind of tasks, but if they are recreated virtually, the feedback information from sense of touch is lost. We designed and ran study with 24 participants to explore the effects of using auditory feedback to communicate this missing information that typists normally get from touching a physical keyboard. The study encompassed four VR mid-air keyboards with increasing levels of auditory information, along with a fifth physical keyboard for reference. We evaluated the auditory augmentations in terms of performance, usability, and workload, while additionally assessing the ability of our technique to communicate the touch-feedback information. Results showed that providing clicking feedback on key-press and key-release improves typing compared to not providing auditory feedback, which is consistent with literature on the topic. However, we also found that using audio to substitute the information contained in physical-touch feedback, in place of actual physical-touch feedback, yielded no statistically significant difference in performance. The information can still be useful, but potentially would take a lot of time to develop the muscle memory reflexes that typists already have when using physical keyboards to type. Nonetheless, we recommend others consider incorporating auditory feedback of key-touch into their mid-air keyboards, since it received the highest levels of user preference among keyboards tested.