title: The effects of visual scenes on roll and pitch thresholds in pilots versus nonpilots.
abstract: BACKGROUND
  Previous studies have indicated that, compared with nonpilots, pilots rely more on vision than "seat-of-the-pants" sensations when presented with visual-vestibular conflict. The objective of this study was to evaluate whether pilots and nonpilots differ in their thresholds for tilt perception while viewing visual scenes depicting simulated flight.
  
  
  METHODS
  This study was conducted in the Advanced Spatial Disorientation Demonstrator (ASDD) at Brooks AFB, TX. There were 14 subjects (7 pilots and 7 nonpilots) who recorded tilt detection thresholds in pitch and roll while exposed to sub-threshold movement in each axis. During each test run, subjects were presented with computer-generated visual scenes depicting accelerating forward flight by day or night, and a blank (control) condition.
  
  
  RESULTS
  The only significant effect detected by an analysis of variance (ANOVA) was that all subjects were more sensitive to tilt in roll than in pitch [F (2,24) = 18.96, p < 0.001]. Overall, pilots had marginally higher tilt detection thresholds compared with nonpilots (p = 0.055), but the type of visual scene had no significant effect on thresholds.
  
  
  CONCLUSIONS
  In this study, pilots did not demonstrate greater visual dominance over vestibular and proprioceptive cues than nonpilots, but appeared to have higher pitch and roll thresholds overall. The finding of significantly lower detection thresholds in the roll axis vs. the pitch axis was an incidental finding for both subject groups.
authors.affiliation: HQ Air Test and Development Command, Japan.
authors.forename: Shinji
authors.initials: S
authors.lastname: Otakeno
authors.forename: Roger S J
authors.initials: RS
authors.lastname: Matthews
authors.forename: Les
authors.initials: L
authors.lastname: Folio
authors.forename: Fred H
authors.initials: FH
authors.lastname: Previc
authors.forename: Charles S
authors.initials: CS
authors.lastname: Lessard
mesh_terms: D000328:Adult; D000337:Aerospace Medicine; D000704:Analysis of Variance; D006801:Humans; D008297:Male; D008875:Middle Aged; D008889:Military Personnel; D009039:Motion Perception / Q000502:physiology*; D010775:Photic Stimulation; D011187:Posture; D011984:Sensory Receptor Cells; D014722:Vestibule, Labyrinth / Q000502:physiology*; D014794:Visual Fields / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*