Depth and Breadth of Pie Menus for Mid-air Gesture Interaction

Mid-air gesture interaction has become one of the most promising human-computer interaction manners. However, the principles of designing pie menus for mid-air gesture interaction are largely lacking. Currently, no study has addressed the breadth and depth of the pie menu for mid-air gesture interaction. Here, in two experiments, we found that the breadth and depth of a pie menu had distinct influences on the operation performance in mid-air gestural interaction: breadth affects both the accuracy and reaction time of the operation, while depth only affects reaction time. Overall, when operation accuracy is the main concern, the breadth of the pie menu will be the key factor, and it should not exceed eight items (Experiments 1 and 2). However, when the operation also emphasizes efficiency, the depth of the pie menu should be considered: fewer layers lead to faster responses, with two layers yielding the best performance (Experiment 2).

Automated summary

Research found that in mid-air gesture interaction, the breadth and depth of a pie menu have different impacts on operation performance: breadth affects accuracy and reaction time, while depth only affects reaction time. When accuracy is prioritized, breadth is key; when efficiency is also a concern, depth is important, with two layers yielding the best performance.