Interactions between Inter- and Intra-Individual Effects on Gaze Behavior

Previous work has shown that gaze behavior can vary not only as a function of stimuli and task but also as a function of the observer. Thereby stable inter-individual differences have been shown as well as changes in gaze behavior due to an observer's internal state. How such intra-individual differences interact with inter-individual variations in gaze behavior has not been studied explicitly before. Here, we tackle this question by analyzing fixation statistics and scan path representations in a visual comparison task inducing different observer states. Results show that reliable inter-individual differences exist in fixations statistics and for scan path representations that allow for modeling a longer temporal horizon. Changes in observer state affected the data, but a substantial amount of variance between observers remained stable. We discuss the results in the light of making personalized gaze-based applications more robust against changes in context.