Blinks, Saccades, and Fixation Pauses during Vigilance Task Performance. I. Time on Task

Civil Aerospace Medical Institute1994PDFTech ReportStern, John A.Boyer, DonnaSchroeder, DavidTouchstone, MarkStoliarov, NikolaiWashington University. Dept. of PsychologyCivil Aeromedical InstituteState Scientific Research Institute for Civil AviationUnited States. Office of Aviation MedicineCivil Aerospace Medical InstituteUnited StatesMonitoringVigilanceAttentionFatigue (Physiological condition)Eye movementsEye fixationsPerformance testsExperimentsHuman subject testingVigilance (Psychology)AttentionFatigueEye--MovementsSaccadic eye movementsPerformance--TestingDOT/FAA/AM-94/26In the future, operators of complex equipment will spend more time monitoring computer controlled devices rather than having hands on control of such equipment. The operator intervenes in system operation under "unusual" conditions or when there is a computer malfunction. The latter occurs relatively seldom. The operator's task thus becomes a "vigilance" task, one requiring attention to monitoring equipment with little need for action. An individual's ability to maintain vigilance is easily compromised, with time-on-task (TOT) a major detractor of performance.The question asked in this research was: Can gaze control measures be used to reflect, and hopefully to predict, periods of impaired vigilance? The results of this study clearly demonstrate that a number of aspects of eye movements and eye blinks show significant TOT effects. These effects are, we believe, more likely to be associated with short periods of attentional lapses or "microsleep" than with more tonic changes in alertness level. The literature dealing with such measures as indicants of "fatigue" and/or "time-on-task" effects is reviewed in considerable detail.The study evaluated aspects of blinking and eye movements in subjects performing the Thackray and Touchstone ATC simulation task. Subjects performed the task for a 2-hour period on 3 separate occasions. Significant increases in blink frequency, blink closing duration, blink flurries, eye closures and fixation pause were obtained as well as similar effects for derivative measures. Though the current data was collected through electrodes attached to the participant, much of the information can be acquired with remote monitoring technologies. This makes possible the application of such measures in a field setting where subjects are required to work on a display terminal. Additional exploration of this approach and the new technologies should provide the information needed to develop strategies and approaches that will enhance operator reliability.121