Improving Discoverability and Expert Performance in Force-Sensitive Text Selection for Touch Devices with Mode Gauges

Text selection on touch devices can be a difficult task for users. Letters and words are often too small to select directly, and the enhanced interaction techniques provided by the OS -- magnifiers, selection handles, and methods for selecting at the character, word, or sentence level -- often lead to as many usability problems as they solve. The introduction of force-sensitive touchscreens has added another enhancement to text selection (using force for different selection modes); however, these modes are difficult to discover and many users continue to struggle with accurate selection. In this paper we report on an investigation of the design of touch-based and force-based text selection mechanisms, and describe two novel text-selection techniques that provide improved discoverability, enhanced visual feedback, and a higher performance ceiling for experienced users. Two evaluations show that one design successfully combined support for novices and experts, was never worse than the standard iOS technique, and was preferred by participants.