Exploring Usability and Learnability of Mode Inferencing in Pen/Tablet Interfaces

The inferred mode protocol uses contextual reasoning and local mediators to eliminate the need to access specific modes to perform draw, select, move and delete operations in a sketch interface. In this paper, we describe an observational experiment to understand the learnability – whether the features are discovered independently – and the usability – user preference and frequency of use – of mode inferencing within a tablet-based sketch application. The experiment showed that those participants instructed in the interface features liked the fluid transitions between draw and lasso selection, but did not like click-select and delete inferencing. As well, interaction techniques were not self-revealing: Participants Submitted for review to IUI 2010. who were not instructed in interaction techniques took longer to learn about inferred mode features and were more negative about the interaction techniques. Together these results inform the future design of pen/tablet interfaces that seek to make use of computational intelligence in support of interaction.