The effects of graphical encodings on reading performance of the data chart displayed on the periphery of attention

Abstract

The accuracy and efficiency of estimating the true data value in visualizations is critical to the user interface design for large displays. As a variable, the attention engagement has not been the focus of existing related studies. In the current study, we intended to measure the performance users estimate proportions from a visualization under the low-attention condition. On this purpose, the dual-task paradigm was employed to simulate the scenario that data charts were read simultaneously with searching and memorizing information on the display. We evaluated eight data charts with three graphical encodings (shape, orientation and area) for the proportion value. The experimental results show that the vertical stacked chart is relatively more suitable for quantitative reading under the situation of temporary distraction. This is reflected by the high accuracy of estimation of this chart with relative less time consumption. When data charts are difficult to read, the users tend to pay less attention to information processing and make more inaccurate inferences of this primary task. Graphical encoding and the task time have a significant effect on task performances overall, while the reading accuracy seems not to vary with the difference of the primary task. The present study can be a supplement to the understanding of graphical perception and provide implications for the design of data visualization in display-human interfaces.