Abstract:
We conducted indoor experiments to investigate whether the virtual reality experience
is affected by pulling the participant’s body to the direction of the acceleration vector
or inertia force in accordance with a video scene of the viewpoint of snowboarder.
Participants viewed the prerecorded 360 video images lasting for 405 seconds via a headmounted
display and performed experiments under three conditions on different days:
No pulling (N), Acceleration (A) and Inertia (I) conditions. They wore snowboard boots
mounted on wooden board (mimic snowboard) and are equipped with waist belt with
ropes that experimenters pulled. We performed psychological measurements (cybersickness,
presence, a sense of agency, and subjective time) and behavioral measurements
(postural instability). To quantify the postural instability, we calculated fluctuations in
center of foot pressure (CoP) throughout the intervention period. The CoPs along a
mediolateral axis (x-axis) and an anteroposterior axis (y-axis) were obtained from
CoPx = −PLT − PLH + PRT + PRH
PLT + PLH + PRT + PRH
and CoPy =
PLT − PLH + PRT − PRH
PLT + PLH + PRT + PRH
where P is a measured value of pressure sensors (at a rate of 200 Hz) installed on left or
right toes and heels. Results of descriptive statistics imply that pulling in either direction
alleviates cybersickness (e.g., Nausea subscale in the Simulator Sickness Questionnaire:
44.5 in N, 28.6 in A, 30.0 in I), slightly improves presence (e.g., presence rating: 4.5
in N, 5.0 in A, 4.9 in I), shortens the perception of time (rating: 68.8 in N, 57.5 in A,
51.7 in I), and increases postural instability (SD(CoPx ): 0.09 in N, 0.23 in A, 0.30 in I;
SD(CoPy ): 0.13 in N, 0.26 in A, 0.35 in I). Moreover, subscales in cybersickness measure
(oculomotor and disorientation symptoms) and the degree of postural instability seems
to depend on pulling directions, suggesting that the direction may be one of considerable
factors to manipulate user’s movements when developing VR training system to acquire
motor skills for accelerated locomotion.
