Measuring Cognitive Load for Map Tasks Through Pupil Diameter

In this paper we use pupil diameter as an indicator for measuring cognitive load for six different tasks on common web maps. Two eye tracking data sets were collected for different basemaps (37 participants and 1,328 trials in total). We found significant differences in mean pupil diameter between tasks, indicating low cognitive load for free exploration, medium cognitive load for search, polygon comparison, line following, and high cognitive load for route planning and focused search. Pupil diameter also changed over time within trials which can be interpreted as an increase in cognitive load for search and focused search, and a decrease for line following. Such results can be used for the adaptation of maps and geovisualizations based on their users' cognitive load.