Introduction: Blinks, saccades, and pupil diameter changes are studied for their application as tools to unobtrusively monitor aspects of performance.
Methods: Subjects performed a running memory task for a 60-min period. To evaluate changes in the relationship of blinks to saccades as a function of time on task, the ratio of blinks occurring with and without saccade was calculated for the second following stimulus termination plus the last 0.2 s of stimulus presentation, and also the second preceding stimulus onset plus the initial 0.2 s of stimulus presentation. Changes in pupil diameter following blinks with and without saccades were measured at the beginning, middle, and late in the experiment.
Results: Blink frequency increased during both periods as a function of time on task (p < 0.0001). The ratio of blinks concurrent with saccades during the post-stimulus period increased as a function of time on task (p < 0.0001). Pupil diameter increased following blink termination (p < 0.05), regardless of time on task, blink duration, or the presence of a saccade during the blink.
Conclusion: Our results suggest that the increase in blinking associated with saccades as a function of time on task, and the pupillary dilation following a blink are associated with aspects of information processing. These results provide a framework for future studies assessing higher-order cognitive function in operational environments based on measurements of blink, pupil, and saccades.