Differential vergence movements in reading Chinese and English: Greater fixation-initial binocular disparity is advantageous in reading the denser orthography

Q J Exp Psychol (Hove). 2017 Jul 11:1-33. doi: 10.1080/17470218.2017.1350866. Online ahead of print.

Abstract

We explore two aspects of exovergence: we test whether smaller binocular fixation disparities accompany the shorter saccades and longer fixations observed in reading Chinese; we test whether potentially advantageous psychophysical effects of exovergence (cf. Arnold & Schindel, 2010; Kersten & Murray, 2010) transfer to text reading. We report differential exovergence in reading Chinese and English: Chinese readers begin fixations with more binocular disparity, but end fixations with a disparity closely similar to that of the English readers. We conclude that greater fixation-initial binocular fixation disparity can be adaptive in the reading of visually and cognitively denser text.

Keywords: Chinese; English; eye-movements; fixations; reading; vergence.