title: [Temporal Analysis of Body Sway during Reciprocator Motion Movie Viewing].
abstract: OBJECTIVE
  We aimed to investigate the effect of stereoscopic viewing and the degree of awareness of motion sickness on posture by measuring body sway during motion movie viewing.
  
  
  METHODS
  Nineteen students (12 men and 7 women; age range, 21-24 years) participated in this study. The movie, which showed several balls randomly positioned, was projected on a white wall 2 m in front of the subjects through a two-dimensional (2-D)/three-dimensional (3-D) convertible projector. To measure body sway during movie viewing, the subjects stood statically erect on a Wii balance board, with the toe opening at 18 degrees. The study protocol was as follows: The subjects watched (1) a nonmoving movie for 1 minute as the pretest and then (2) a round-trip sinusoidally moving-in-depth-direction movie for 3 minutes. (3) The initial static movie was shown again for 1 minute. Steps (2) and (3) were treated as one trial, after which two trials (2-D and 3-D movies) were performed in a random sequence.
  
  
  RESULTS
  In this study, we found that posture changed according to the motion in the movie and that the longer the viewing time, the higher the synchronization accuracy. These tendencies depended on the level of awareness of motion sickness or the 3-D movie viewed.
  
  
  CONCLUSIONS
  The mechanism of postural change in movie viewing was not vection but self-defense to resolve sensory conflict between visual information (spatial swing) and equilibrium sense (motionlessness).
authors.affiliation: Graduate School of Information Science, Nagoya University.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Sugiura
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Tanaka
authors.forename: Shun
authors.initials: S
authors.lastname: Wakatabe
authors.forename: Chika
authors.initials: C
authors.lastname: Matsumoto
authors.forename: Masaru
authors.initials: M
authors.lastname: Miyao
mesh_terms: D001296:Audiovisual Aids; D005260:Female; D006801:Humans; D008297:Male; D009038:Motion; D011187:Posture; D055815:Young Adult