Abstract. Two-handed, multi-touch surface computing provides a scope for interactions that are closer analogues to physical interactions than classical win-dowed interfaces. The design of natural and intuitive gestures is a difficult prob-lem as we do not know how users will approach a new multi-touch interface and which gestures they will attempt to use. In this paper we study whether fa-miliarity with other environments influences how users approach interaction with a multi-touch surface computer as well as how efficiently those users complete a simple task. Inspired by the need for object manipulation in infor-mation visualization applications, we asked users to carry out an object sorting task on a physical table, on a tabletop display,...