Evaluating Mid-air List Interaction for Spatial Audio Interfaces.

ABSTRACTSelecting items from lists is a common task in many applications. For wearable devices where no display is available, list selection can be challenging. To explore potential solutions we present four user studies evaluating mid-air gestures to interact with lists in an eyes-free interface. We found that a spatialized audio list in the shape of a 110~degree arc angled towards the dominant hand was a comfortable and usable layout for most users. A selection takes less than 10.6 seconds on average and error rates are below 4% when users locate and select an item in an unknown, unordered list of 20 items. For lists of 10 items the mean selection time is 5.5 seconds or less, and error rates drop below 1.4%. We compared monophonic to binaural playback of feedback sounds (musicons) and found no statistical difference for task completion times or error rates between the conditions. We also implemented and evaluated a music player application to showcase spatial audio list selection in an applied scenario.