Relative role of merging and two-handed operation on command selection speed

This paper examines the influence of two interface characteristics on command selection speed: the integration of command selection with direct manipulation (merging), and two-handed operation. We compared four interaction techniques representing combinations of these characteristics (Marking Menu, Two-handed Tool Palette, Toolglass, and Control Menu). Results suggest that the one-handed techniques selected for the present study produced a speed advantage over two-handed techniques, whereas the influence of merging was task dependent. A follow-up study examining Bimanual Marking Menu suggests that the performance of two-handed techniques may be reduced due to a split in visual attention required for certain techniques. Taken together, these findings have important implications for the design of command selection mechanisms for pen-based interfaces.