Abstract

Scrolling interactions are an important aspect of the design of usable touchscreen interfaces, particularly for handheld devices that can only display a limited amount of information at once. Using a touchscreen capable of dynamically altering its surface friction, we explore the design space of haptically-augmented scrolling interactions and investigate programmable friction's ability to provide appropriate feedback in envisioned usage scenarios. We performed five user experiments to evaluate respectively the identifiability of a set of iconic detents, the countability of detents, the perception of detent density, the synchronization of tactile feedback to on-screen events, and the optimal friction pattern for a spring-like resistance. The results of these experiments provide valuable information that will inform the design of scrolling interactions that leverage programmable friction for an improved user experience.