Assessing ocular activity during performance of motor skills using electrooculography

Eye-tracking research has revealed that, compared to novices, expert performers make longer ocular fixations on the target of an action, that is they have a longer quiet eye. Remarkably, the reason why a longer quiet eye aids movement has yet to be established. There is a need for interdisciplinary research and new measures of ocular activity to accelerate progress on the mechanistic understanding of the phenomenon. With the aim to provide researchers in this field with new tools, we assessed the utility of electrooculography (EOG) to examine ocular activity while 10 experts and 10 novices putted golf balls. We measured quiet eye durations, distinguishing its pre- and post- movement initiation components, and developed a novel time-varying index of ocular activity, eye quietness, computed as the variability of the EOG in short time intervals: lower values correspond with greater quietness. Finally, we measured movement durations using a combination of infrared and sound sensors. Experts had longer post-movement initiation quiet eye compared to novices; however, total and pre-movement quiet eye durations did not differ between groups. Eye quietness was inversely correlated with quiet eye duration, and was greatest immediately after movement initiation. Importantly, movement duration correlated positively with post-movement initiation quiet eye and negatively with eye quietness shortly after movement initiation. This study demonstrates the utility of assessing ocular activity during performance of motor skills using EOG. Additionally, these findings provide evidence that expert-novice differences in ocular activity may reflect differences in the kinematics (e.g., movement duration) of how experts and novices execute motor skills.