How Do People Parse Dynamic Maps? Insights from Event Segmentation Experiments (Short Paper)

Dynamic thematic maps can visualize spatiotemporal phenomena but have been found to be perceptually and cognitively challenging for users. The cognitive process of event segmentation describes how people parse the complex and continuous experiences of everyday life into discrete events, facilitating further processing. This research explores how segmentation processes impact the perception of dynamic thematic maps. Specifically, we investigate if conceptual and perceptual influences on segmentation generalize to depictions of spatiotemporal data on dynamic maps. In two within-subjects experiments, participants (N = 125, 176) segmented 32 maps displaying insect population densities over time. We manipulated participants’ expectations of the trend in population density and the salience of the direction of the trend. The results show that viewers' expectations, as well as change salience (both through color scale and spatial pattern of change), impact how similarly participants place event boundaries. Our research on the interindividually shared processing of dynamic map data extends key event segmentation findings to the field of spatial cognition. At the same time, it takes a step towards researching design measures for facilitating the processing of dynamic maps rooted in cognitive theories.