Review of eye tracking metrics involved in emotional and cognitive processesVasileios Skaramagkas, Giorgos Giannakakis et al.Eye behaviour provides valuable information reveal- ing one’s higher cognitive functions and state of affect. Although eye tracking is gaining ground in the research community, it is not yet a popular approach for the detection of emotional and cognitive states. In this paper, we present a review of eye and pupil tracking related metrics (such as gaze, fixations, saccades, blinks, pupil size variation, etc.) utilized towards the detection of emotional and cognitive processes, focusing on visual attention, emotional arousal and cognitive workload. Besides, we investigate their involvement as well as the computational recognition meth- ods employed for the reliable emotional and cognitive assessment. The eye-tracking publicly available datasets employed in relevant research efforts were concentrated and described their specifi- cations and details. The multimodal approaches which combine eye-tracking features with other modalities (e.g. biosignals), along with artificial intelligence and machine learning techniques were also surveyed in terms of their recognition/classification accuracy. The limitations, current open research problems and prospective future research directions were discussed for the usage of eye- tracking as the primary sensor modality. This study aims to comprehensively present the most robust and significant eye/pupil metrics based on available literature towards the development of a robust emotional or cognitive computational model. Index Terms—eye tracking, gaze, pupil, fixations, saccades, smooth pursuit, blinks, stress, visual attention, emotional arousal, cognitive workload, emotional arousal datasets, cognitive work- load datasets Vasileios Skaramagkas, Giorgos Giannakakis, Emmanouil Ktistakis, Dim- itris Manousos, Ioannis Karatzanis are with the Institute of Computer Science, Foundation for Research and Technology Hellas (FORTH), GR-700 13 Heraklion, Crete, Greece (Email: vskaramag@ics.forth.gr, ggian@ics.forth.gr, mandim@ics.forth.gr, karatzan@ics.forth.gr) Giorgos Giannakakis is with the Institute of AgriFood and Life Sciences, University Research Centre, Hellenic Mediterranean University, Heraklion, Greece. Emmanouil Ktistakis is with the Institute of Computer Science, Foundation for Research and Technology Hellas (FORTH) and the Laboratory of Optics and Vision, School of Medicine, University of Crete, Heraklion, Greece (Email: mankti@ics.forth.gr) Nikolaos S. Tachos and Evanthia E. Tripoliti, are with the Department of Biomedical Rese
