Transient and transitional states: pressure as an auxiliary input modality for bimanual interaction.

A novel investigation of pressure input is presented where it is characterised as a transient modality, one that has a natural inverse, bounce-back and a state that only persists during interaction. Three empirical studies are described that evaluate pressure for use as a non-dominant hand input modality, where the ability to target and maintain pressure while simultaneously performing a dominant-hand targeting task is investigated. Pressure accuracy was high (93%) and the impact on dominant-hand targeting was low. Mean pressure accuracy when selecting targets by releasing pressure was also high (89%) as was selecting targets by applying pressure from a non-zero starting point (94.4%). The ability to accurately maintain pressure over time was better with larger target pressures. Example applications and design guidelines are presented that enable designers to exploit the transient properties of pressure input in interaction design.