If Your Mind Can Grasp It, Your Hands Will Help

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.