Usability Impact of Occlusion-free Techniques on Commonly-used Multitouch Actions

Many interaction techniques have been proposed to combat the finger occlusion and precision problem in multitouch platforms such as tablets and smartphones, supporting more accurate ways to select a target item with a finger. Recognising how the typical touch interactions on multitouch platforms are becoming more complex and composite, in this paper we study some combinations of basic occlusion-free/precision finger interaction techniques in the context of commonly-used composite user actions in realistic usage scenarios including copying and pasting a portion of text and drawing a curved line. We develop full-fledged tablet applications featuring the techniques to assess their usability impact on the rest of the actions. Usability testing with 25 participants qualitatively reveals how the integration of these techniques is useful for their intended part (i.e. accurate targeting) but negatively influence the remaining parts of the action. Insights from the study and areas that will benefit further investigation are discussed.