Orientation of microsaccades during reading

Microsaccades are small eye movements during what is usually called a „fixation“; during reading they may displace the eye within the fixated letter. In spatial cueing, microsaccades were oriented in cue direction while waiting for a target stimulus [Engbert, R., & Kliegl, R., Binocular coordination in microsaccades. In J. Hyönä, R. Radach, & H. Deubel (Eds.), The mind’s eye: Cognitive and applied aspects of eye movement research (in press). Elsevier Science: New York, Amsterdam(2003)]. Here we investigated the orientation of microsaccades in reading fixations. Sixty-six subjects (33 young, 33 elderly) read 144 sentences. We determined the relation between microsaccade orientation angle and the following saccade (forward vs. regressive saccades). Fixations with binocular right-orientated microsaccades were more likely to be followed by a forward saccade than a regression. Fixations with binocular left-orientated microsaccades were more likely to be followed by a regression than a forward saccade. In a control analysis, no systematic relations were found to the orientation of the saccade prior the current fixation. The results suggest that binocular microsaccades may be predictive of orientation of attention shifts in reading.