Understanding and Improving the Performance of Action Pointing

Action pointing involves choosing and executing an action at a specific place in the workspace (e.g., choosing a tool and clicking to start drawing, or selecting an object and copying with a shortcut). The elements of action pointing (choosing an action, specifying a position, and triggering the action) can be carried out in many ways – and our analysis of current techniques identified limitations on performance, particularly for repeated sequences of interactions. To empirically analyse interaction alternatives for action pointing, we developed and evaluated two techniques: ModeKeys removes modifier keys from keyboard shortcuts used to choose actions; AimKeys goes further by using the shortcut (not the mouse) to trigger the action. Three studies over three tasks showed that these reconfigurations were highly effective –- in all studies, either AimKeys or ModeKeys were faster, easier, and preferred overall. Our studies show that small variations in the configuration of action pointing can have a large impact, offering opportunities to improve performance with direct-manipulation systems.