Abstract-The importance of interaction to Information Visualization (InfoVis) and, in particular, of the interplay between interactivity and cognition is widely recognized [12, 15, 32, 55, 70] . This interplay, combined with the demands from increasingly large and complex datasets, is driving the increased significance of interaction in InfoVis. In parallel, there have been rapid advances in many facets of interaction technologies. However, InfoVis interactions have yet to take full advantage of these new possibilities in interaction technologies, as they largely still employ the traditional desktop, mouse, and keyboard setup of WIMP (Windows, Icons, Menus, and a Pointer) interfaces. In this paper, we reflect more broadly about the role of more "natural" interactions for InfoVis and provide opportunities for future research. We discuss and relate general HCI interaction models to existing InfoVis interaction classifications by looking at interactions from a novel angle, taking into account the entire spectrum of interactions. Our discussion of InfoVis-specific interaction design considerations helps us identify a series of underexplored attributes of interaction that can lead to new, more "natural," interaction techniques for InfoVis. Index Terms-Design considerations, interaction, post-WIMP, NUI (Natural User Interface). The importance of interaction to Information Visualization (InfoVis) and, in particular, of the interplay between interactivity and cognition is widely recognized [12, 15, 32, 55, 70] . Interaction particularly rises in significance in InfoVis as we engage with increasingly large and complex datasets. Many tasks on visualized data can no longer be completed using static images alone. As a consequence, information workers request more and more interactive data analysis instruments [18] . In addition, a general audience is beginning to create visualizations using data of their own interest [49, 72, 80] . The creation of visualizations and the exploration of data have a number of dedicated underlying interaction requirements causing challenges that visualization research is just beginning to address. In parallel, but independently of the proliferation of InfoVis, interface and interaction technology have been advancing rapidly. The wide adoption of touch-enabled phones and multi-touch slates shows people's increasing affection for mouse-less interfaces, often referred to in the media as Natural User Interfaces (NUIs) [26, 75] . Advances in input technology have, however, also included other types of new display hardware such as screens of many different sizes and shapes, transparent [77] Despite the recognition of the importance of interaction to InfoVis, comparatively little has been done to take advantage of the advances made in the interaction design community. InfoVis systems largely remain operational using the classic desktop, mouse, and keyboard setup. With this setup, principles of "point and click" WIMP GUIs (graphical user interfaces based on windows, icons, menus, and a pointer) and direct manipulation are the most common underlying models to design InfoVis interfaces. We argue that post-WIMP interfaces are still relatively underexplored in InfoVis and could augment or complement WIMP for InfoVis for several reasons: a) A well-known critique of WIMP interfaces is "drowning in functionality" where options have to be found in multi-step hierarchical menus or between multitudes of buttons, checkboxes, and other widgets [17] . InfoVis often has complex sets of data-, representation-, and presentation-centric options, and thus "drowning in functionality" is a concern for the usability of InfoVis systems. b) InfoVis often deals with multi-dimensional data. The mapping of multi-dimensional data tasks to 2D widgets may not be particularly natural. An example where this becomes evident is widgets for 3D navigation in information spaces [17] . c) InfoVis-even if designed for a concise overview-can quickly achieve a high-level of visual complexity which may further conflict with WIMP interfaces [17] . d) InfoVis is moving into new contexts (e.g., museums, meeting rooms, public spaces, and hand-held devices) and targeting a broader range of audiences with requirements of "anytime/anywhere" data access. It is known that WIMP interfaces are not the most appropriate interface for many display or analysis environments [75] . Given these possibilities of post-WIMP interfaces for InfoVis, an in-depth discourse and further research about alternative visualization interactions is needed. One example in this direction is a recent discussion by Elmqvist et al., which begins to advocate more careful interaction design and attempts to characterize successful fluid interaction in InfoVis [21] . Similarly, our goal in this paper is to reflect more broadly about the role of more "natural" interaction for InfoVis and to provide opportunities for future research. We organize this paper as follows. We first summarize existing interaction models proposed by the HCI community, review how the InfoVis community classifies InfoVis-specific interactions, and describe the advances both in hardware and software technologies supporting post-WIMP interfaces. This process led us to consider missing perspectives and reflect on the role of interactions in InfoVis. From this, we derived design considerations in which we look at interactions from a novel angle, taking into account the entire spectrum of interactions that can be of value to consider in InfoVis. Finally, we discuss opportunities and challenges that guide us to future research directions.
REF argued more generally for the adoption of novel interaction modalities for information visualization.
Beyond Mouse and Keyboard: Expanding Design Considerations for Information Visualization Interactions
IEEE Transactions on Visualization and Computer Graphics
IEEE Transactions on Visualization and Computer Graphics
Computer Science Medicine