Background: For virtual environments (VEs) to be useful in training it is important to understand the negative effects of VE exposure. The purpose of this study was to observe head movements in virtual and real environments and the relation between those movements and simulator sickness.
Method: There were 48 men who were trained in 4-person teams in either a head-mounted display (HMD)-based VE or in a real world environment. Head position data were collected in both systems and simulator sickness scores were collected in the VE. The relationship of head movements and sickness scores in theVE was examined and the degree of head movements in the real world and VE compared.
Results: Differences were found in the length of time subjects spent moving their heads; subjects with the highest sickness scores moved their heads less often than other subjects in the VE. Also, subjects moved their heads significantly less and less often in the VE (means: 3 degrees x 50 ms(-1), 71% of trial time not moving head), compared to the real world (means: 10 degrees 50 ms(-1), 59% of trial time not moving head).
Conclusions: This study observed that when head movements are quantified, past assumptions of the link between increased sickness scores and decreased head movements may not hold. Though not linked to simulator sickness, head movements were reduced in the VE compared to the real world. Though observational in nature, this study is one of the first to quantify head movements and how they may relate to simulator sickness.