title: Task performance and eye activity: predicting behavior relating to cognitive workload.
abstract: BACKGROUND
  The focus of this study was to examine oculomotor behavioral changes while subjects performed auditory and driving tasks.
  
  
  METHODS
  There were 13 participants who completed 3 10-min tasks consisting of driving only, the Paced Auditory Serial Addition Task (PASAT) only, and a dual task of both driving and auditory tasks. For each participant, changes in six measures were assessed as a function of cognitive workload, specifically changes in eye activity, including blink frequency, blink duration, fixation frequency, fixation duration, pupil diameter, and horizontal vergence. In addition, deviations in lateral lane position were assessed as a measure of driving behavior.
  
  
  RESULTS
  Compared with the subjects' behavior in the driving-only task, results showed an increase in blink frequency during the combined driving and auditory task. Also, during the dual task the mean pupil diameter and horizontal vergence increased when subjects performed well in the auditory task in contrast to when the subjects performed poorly. Evidence of visual tunneling or reduced range of scanning and decreases in rearview mirror and odometer glances appeared when subjects performed the driving and auditory dual task. There was no significant change in fixation frequency. However, decreased fixation duration appeared to predict upcoming errors in the auditory task. Pupil diameter changes were significantly higher when performing well on the auditory task than when subjects were performing poorly.
  
  
  CONCLUSIONS
  Eye behavior trends reported in this study may provide insight to human behavior corresponding with cognitive workload, which may in turn be utilized to produce reliable workload indicators and applications that predict poor performance in real time.
authors.affiliation: Naval Health Research Center, San Diego, CA, USA.
authors.forename: Yi-Fang
authors.initials: YF
authors.lastname: Tsai
authors.forename: Erik
authors.initials: E
authors.lastname: Viirre
authors.forename: Christopher
authors.initials: C
authors.lastname: Strychacz
authors.forename: Bradley
authors.initials: B
authors.lastname: Chase
authors.forename: Tzyy-Ping
authors.initials: TP
authors.lastname: Jung
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001307:Auditory Perception / Q000502:physiology; D001334:Automobile Driving; D003071:Cognition / Q000502:physiology*; D005133:Eye Movements / Q000502:physiology*; D005221:Fatigue / Q000503:physiopathology; D005260:Female; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D013647:Task Performance and Analysis; D014796:Visual Perception / Q000502:physiology; D016526:Workload