Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)

Legacy Department

Human Factors Psychology

Committee Member

Dr. Eric R. Muth, Committee Chair

Committee Member

Dr. Adam W. Hoover

Committee Member

Dr. Benton D. Lawson

Committee Member

Dr. Christopher C. Pagano


The purpose of this study was to determine how latency in a head-mounted display affects human performance. Virtual environments are used frequently for training, however simulator sickness is a common problem and may affect transfer of training. Aspects of virtual environments that cause simulator sickness are not fully understood, but varying latency has been shown to increase simulator sickness symptoms. The impact of varying latency on task performance and the interaction between performance and simulator sickness symptoms has not been examined. Twenty-nine subjects (15 male) participated in a repeated measures study in which they were exposed to two different latency conditions in a Head-Mounted Display (HMD): constant (70 ms) and varying (70 ms – 270 ms). Experimental sessions were separated by 14-daysto minimize the effects of adaptation. While wearing the HMD, subjects used a laser pointer to repeatedly "shoot" at 8 laser targets, arrayed in a 180-degree arc around the lab,over the course of 200 trials per session, presented in 5 blocks of 40 trials. Sickness levels, accuracy and time-to-hit data were recorded for analysis. Subjects scored fewer hits and took longer to hit targets in the varying latency condition, F (1,54) = 35.20, p < .01, 2p = .40, than in the constant latency condition F (4,51) = 13.50, p < .01, 2 p = .51. These findings indicate that individuals exposed to varying latency performed worse than individuals exposed to constant latency. However, it is unclear if the performance effects are due mostly to the latency itself or another underlying causal influence such as simulator sickness.