Dual-Surface input: augmenting one-handed interaction with coordinated front and behind-the-screen input

Interaction patterns with handheld mobile devices are constantly evolving. Researchers observed that users prefer to interact with mobile device using one hand. However, only few interaction techniques support this mode of operation. We show that one-handed operations can be enhanced with coordinated interaction using for input the front and back of a mobile device, which we term as Dual-Surface interaction. We present some of the design rationale for introducing coordinated Dual-Surface interactions. We demonstrate that several tasks, including target selection, benefit from Dual-Surface input which allows users to rapidly select small targets in locations that are less accessible when interacting using the thumb with one-handed input. Furthermore, we demonstrate the benefits of virtual enhancements that are possible with behind-the-display relative input to perform complex tasks, such as steering. Our results show that Dual-Surface interactions offer numerous benefits that are not available with input on the front or the back alone.