Eye Movement Metrics as Indicator of Cognitive Loading: A Systematic Review

Cognitive load refers to the mental effort being used in the working memory for carrying out a specific task. With increased task complexity, task difficulty level increases, requiring more of the cognitive resources, resulting in higher cognitive load. Cognitive overload not only affects physical and mental issues but also affects the work efficiency and safety. Thus, researches on quantifying cognitive load is important in the fields of education, vehicle driving, product designing, human-computer interaction, various industries and Military workstations. This review article investigates past researches to identify most suitable and usable method of quantifying and interpreting cognitive loading of a given task. Among subjective, behavioural and physiological measures, physiological measures are more practical, providing instantaneous quantification of cognitive load in a given timeline with higher levels of objectivity. However, apart from Eye movement recording, in all other methods, the participants need to wear sensors which may pose hindrance to the task being carried out or it may not be convenient or comfortable to wear these sensors, usually on the skin, throughout the assessment time. This review paper reports significant association of eye movement profiles with human cognition. It further concludes that measuring eye movement parameters could be considered as a potential method to interpret the cognitive abilities of participants engaged in different activities.