Abstract: 

Recent research suggests that the different components of eye movements (fixations, saccades) are not strictly separate but are interdependent processes. This argument rests on observations that fluctuations in eye-movment signals yield unimodal distributions and exhibit power-law scaling, indicative of interdependent processes coordinated across timescales. The studies that produced these findings, however, employed complex tasks (visual search, scene perception). Thus, the question is whether the observed interdependence is a fundamental property of eye movements or emerges in the interplay between cognitive processes and complex visual stimuli. In two studies, we have investigated whether simple eye-movement tasks that do not put high cognitive demands on participants also exhibit power-law scaling, and whether power-law scaling can also be found in the time-domain of eye-movement fluctuations. Both studies show that power-law scaling is also present in simple eye-movements, suggesting that it is a genuine property of eye-movement behaviour. Furthermore, additional results show that power-law scaling is a better predictor for task performance aspects (such as subjective task effort) than traditional eye-movement statistics. Finally, the observations that power-law scaling might be a fundamental properties of eye-movements also has bearings on contemporary research questions, for example regarding the reliably quantification of fixations, or the discovery of increasingly smaller saccadic components (i.e., saccades, micro-saccades, minimal-saccades…).

Contact: Sebastian Wallot