A Smartwatch Moves: The Impact of Walking Speed and Trajectories on Micro Visualizations Reading on a Smartwatch.

We describe the impact of smartwatch wearers' motion on how effectively wearers can read micro visualizations, how challenging the task feels, and how these effects relate to smartwatch orientation. Visual information on smartwatches is often consumed in dynamic contexts that involve motion such as walking or running. Motion can introduce perceptual challenges due to the way people position their smartwatch, increasing the general task load, but these effects have not been systematically studied. Therefore, we measured smartwatch viewing postures and performance data while reading visualizations in two studies. These studies examined different walking trajectories and speeds with stationary baseline conditions. Our results show that walking and trajectory type altered smartwatch positioning and wrist orientation, with faster speeds increasing these effects. Walking, particularly at higher speeds, also reduced reading accuracy and sometimes increased response times, while participants also slowed their pace when reading micro visualizations. Based on these findings, we propose design considerations including additional visual cues and visualization size adaptations for different viewing postures to support glanceable micro visualizations in motion.