Physical Visualizations are currently mostly used in casual contexts, e.g., as artistic data sculptures. However, their measurable benefits for traditional information visualization are largely unexplored. As a step in this direction, we compared the memorability of physical visualizations to that of digital visualizations. We conducted a user study with 40 participants in which we measured the recall of three types of information immediately after exploration and with a delay of two weeks. The results show that the physical visualization led to significantly less information decay within this time span. Our results build on known effects from cognitive psychology and provide a first indicator for measurable benefits of physical visualizations regarding memorability.Information Visualization (InfoVis) helps users to explore and understand large amounts of abstract data. While digital visualizations are well-explored, physical visualizations which map data to physical form instead of pixels recently started to attract attention [6,7,11]. Reasons for this are the progress in digital fabrication technologies, such as laser cutters and 3D printers [12], as well as recent developments in the field of shape changing displays (e.g., [4]). The fact that such technologies are becoming increasingly commonplace, prompts further research on how digital and physical visualizations can complement one another and to explore areas in which physical visualizations can have benefits.Jansen et al.[7] compared physical 3D bar charts to their onscreen counterparts and found that physical outperformed onscreen 3D bar charts, but 2D visualizations performed best for all of the tested low-level information retrieval tasks. In their outlook they suggest, that future studies should investigate other factors than pure performance. Figure 1. Static physical bar chart which was used in our study and a close-up on the bars' labeling and the background panel.Visualizations can actually extend human memory [13], and memorability therefore is a frequently discussed topic in InfoVis (e.g., [1,5]). There are indications that visual and haptic perception are processed dependently [9] and that vision and haptics share common abstract representations of the shape and structure of objects [3]. Furthermore it has been shown that spatial layouts, which were learned through haptic and visual exploration, are stored within a common reference frame: Haptic experiences were able to influence memories that were acquired visually [8]. Previous studies also revealed that physical objects were recalled more frequently than pictures, and pictures more often than words [2].All of this suggests that a physical representation, for example of a bar chart, could generate a more detailed representation in the subjects' memory and hence be more memorable than its digital on-screen representation.In a study with 40 participants we compared a physical bar chart (see figure 1) to the same chart displayed on a tablet screen. Memory performance was measured by a questionnai...

Abstract-Backstage is a digital backchannel that is carefully designed for the use in large lecture classes. The goal of Backstage is to support social and active learning in a mainly impersonal and passive learning setting. In classes with a large and anonymous audience, passivity can be a cause of lowered awareness. This paper introduces Backstage and discusses its range of functions in the light of how it contributes to awareness. It furthermore introduces newly conceived concepts by which information are collected and properly displayed in order to help both students and lecturer to gain insight about who is around, what are the kinds of activities the community is engaged in, and what matters in the lecture.