Two-Handed Marking Menus for Multi-Touch Devices
The authors investigate multi-stroke marking menus for multi-touch devices and they show that using two hands can improve performance. They present two new two-handed multi-stroke marking menu variants in which users either draw strokes with both hands simultaneously or alternate strokes between hands. In a pair of studies they find that using two hands simultaneously is faster than using a single, dominant-handed marking menu by 10-15%. Alternating strokes between hands doubles the number of accessible menu items for the same number of strokes, and is similar in performance to using a one-handed marking menu. They also examine how stroke direction affects performance. When using thumbs on an iPod Touch, drawing strokes upwards and inwards is faster than other directions.