A review of gaze entropy as a measure of visual scanning efficiency

Brook Shiferaw; Luke Downey; David Crewther

doi:10.1016/j.neubiorev.2018.12.007

A review of gaze entropy as a measure of visual scanning efficiency

Neurosci Biobehav Rev. 2019 Jan:96:353-366. doi: 10.1016/j.neubiorev.2018.12.007.

Authors

Brook Shiferaw¹, Luke Downey², David Crewther³

Affiliations

¹ Centre for Human Psychopharmacology, Swinburne University of Technology, Hawthorn, Australia. Electronic address: bshiferaw@swin.edu.au.
² Centre for Human Psychopharmacology, Swinburne University of Technology, Hawthorn, Australia; Institute for Breathing and Sleep, Austin Hospital, Melbourne Australia.
³ Centre for Human Psychopharmacology, Swinburne University of Technology, Hawthorn, Australia.

PMID: 30621861
DOI: 10.1016/j.neubiorev.2018.12.007

Abstract

While the concept of entropy has been applied to gaze analysis, it is unclear what aspects of visual scanning it measures. In this review, we first outline gaze control as a complex system of spatial prediction. Second, we provide a brief introduction to the concept of entropy within the context of information theory as the foundation for gaze entropy measures; with a specific focus on equations for Shannon's entropy and conditional entropy. The application of these equations to gaze data is described as stationary gaze entropy (SGE) and gaze transition entropy (GTE) respectively. Third, we present an updated model of gaze orientation and propose an adaptable definition of GTE as a measure of visual scanning efficiency that underlies overall gaze dispersion measured by SGE. Finally, we review studies that have utilised GTE and SGE to assess visual scanning and discuss their results in relation to our proposed definitions and associated hypotheses. Methodological limitations in gaze entropy measures are discussed and suggestions provided to improve interpretability and generalisability of future studies.

Keywords: Fixations; Gaze; Gaze entropy; Visual scanning.

Publication types

Research Support, Non-U.S. Gov't
Review

MeSH terms

Appetitive Behavior*
Entropy
Eye Movements*
Humans
Information Theory
Models, Biological
Psychophysics
Visual Perception*