Humans have represented data in many forms for thousands of years, yet the main sensory channel we use to perceive these representations today still remains largely exclusive to sight. Recent developments, such as advances in digital fabrication, microcontrollers, actuated tangibles, and shape-changing interfaces offer new opportunities to encode data in physical forms and have stimulated the emergence of 'Data Physicalization' as a research area.

This paper describes a study comparing the information recall of participants using 2D and 3D physical visualizations. Specifically, it focuses on physical bar charts and evaluates the difference between a paper-based visualization and a version built with wooden blocks. We conducted a repeated measures study involving 16 participants in which we measured the recall of information immediately after the exploration and with a delay of one week. We used questionnaires and semi-structured interviews to obtain more information about the process of recall and participants' opinions whether and how the visualizations differ in their potential for memorizing information. The results point out that participants believe to remember the 3D visualizations better, but besides the recall of extreme values the quantitative data cannot completely verify this appreciation. Furthermore the results highlight that the in the study used physical interaction techniques are not able to compensate lacking visual differentiation. One surprising finding was the strong dependency of the different data sets on the recall performance.

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.

Although physical objects have been used for information presentation for a long time, physical visualizations only recently started to attract interest in the HCI and InfoVis communities. While physical visualizations have the quality to evoke user fascination and curiosity, our understanding of their benefits regarding data exploration and the creation of effective representations are still limited. This paper describes several projects in the area of physical visualizations, all with the goal to explore their potential and limitations. First findings show that a promising direction of physical visualizations is the area of personal data, where they can offer a more creative and mindful way to look and reflect on ones' data.

Data sculptures are a promising type of visualizations in which data is given a physical form. In the past, they have mostly been used for artistic, communicative or educational purposes, and designers of data sculptures argue that in such situations, physical visualizations can be more enriching than pixel-based visualizations. We present the design of Activity Sculptures: data sculptures of running activity. In a three-week field study we investigated the impact of the sculptures on 14 participants' running activity, the personal and social behaviors generated by the sculptures, as well as participants' experiences when receiving these individual physical tokens generated from the specific data of their runs. The physical rewards generated curiosity and personal experimentation but also social dynamics such as discussion on runs or envy/competition. We argue that such passive (or calm) visualizations can complement nudging and other mechanisms of persuasion with a more playful and reflective look at ones' activity.