Blended Interaction: understanding natural human–computer interaction in post-WIMP interactive spaces

We introduce Blended Interaction, a new conceptual framework that helps to explain when users perceive user interfaces as \"natural\" or not. Based on recent findings from embodied cognition and cognitive linguistics, Blended Interaction provides a novel and more accurate description of the nature of human---computer interaction (HCI). In particular, it introduces the notion of conceptual blends to explain how users rely on familiar and real-world concepts whenever they learn to use new digital technologies. We apply Blended Interaction in the context of post-\"Windows Icons Menu Pointer\" interactive spaces. These spaces are ubiquitous computing environments for computer-supported collaboration of multiple users in a physical space or room, e.g., meeting rooms, design studios, or libraries, augmented with novel interactive technologies and digital computation, e.g., multi-touch walls, tabletops, and tablets. Ideally, in these spaces, the virtues of the familiar physical and social world are combined with that of the digital realm in a considered manner so that desired properties of each are preserved and a seemingly \"natural\" HCI is achieved. To support designers in this goal, we explain how the users' conceptual systems use blends to tie together familiar concepts with the novel powers of digital computation. Furthermore, we introduce four domains of design to structure the underlying problem and design space: individual and social interaction, workflow, and physical environment. We introduce our framework by discussing related work, e.g., metaphors, mental models, direct manipulation, image schemas, reality-based interaction, and illustrate Blended Interaction using design decisions we made in recent projects.