Studying Eye Movements as a Basis for Measuring Cognitive Load

Users' cognitive load while interacting with a system is a valuable metric for evaluations in HCI. We encourage the analysis of eye movements as an unobtrusive and widely available way to measure cognitive load. In this paper, we report initial findings from a user study with 26 participants working on three visual search tasks that represent different levels of difficulty. Also, we linearly increased the cognitive demand while solving the tasks. This allowed us to analyze the reaction of individual eye movements to different levels of task difficulty. Our results show how pupil dilation, blink rate, and the number of fixations and saccades per second individually react to changes in cognitive activity. We discuss how these measurements could be combined in future work to allow for a comprehensive investigation of cognitive load in interactive settings.publishe