Virtual Environment Sickness (sometimes referred to as VES or as Simulation Sickness) was first officially researched by the United States Air Force back in the 1990s after the unexpected deaths of two experienced Air Force pilots.
It was determined to affect between 20 and 30% of the general population, and is more commonly experienced these days in assorted video games, though not usually with any deadly consequences.
Virtual Environment Sickness is a form of motion-sickness and motion disorientation that is sometimes characterized by a tingly, queasy feeling possibly accompanied by vertigo – the sort you might get standing right on the roof edge of a very tall building.
The first death linked to VES was a car accident. An experienced test-pilot with superb reflexes died in a car accident, not too long after a session in a simulator. Later, another pilot died under similar circumstances, prompting a fuller military investigation in 1995.
The cause was ultimately determined to be an interference with the normal neurological processing of information for orientation, motion and distance, the same sort of thing that makes you motion-sick and sea-sick. In a simulator, using a virtual environment, in microgravity or on a boat, your body’s vestibular system for determining orientation and motion disagree with what your eyes tell you is happening. It’s that cognitive dissonance that generates the queasy feelings.
Nobody’s quite certain why queasiness is linked to this neurological dissonance, but a commonly held theory is that it is an evolved response to various forms of poisoning, as disruptions to equilibrium and balance have often resulted from bad food, which the body is then encouraged to eject.
Most of us are able to quell the interference, and accept one set of conflicting inputs or the other – usually both, reconciling the two different indications of motion. Not everyone can, and various forms of motion sickness are considered a not unhealthy response to stimuli.
Even so, the US pilots died because of a lingering dissonance between imagery perceived by the eyes, and cues delivered from the inner-ear and other biomechanical mechanisms. Their perceptions of speed and motion were distorted for a time in the wake of simulator sessions and it impaired their ability to control their automobiles correctly.
For most of us, though, outside of lovingly-detailed simulated cockpits, the confusion of signals in the wake of VES is fairly weak, and doesn’t present a significant risk. After prolonged virtual environment and gaming sessions, you might want to take a short nap before driving, especially if the game is one that tends to give you a bit of a tingle in the stomach.
For me, the Tomb Raider games did this often, as did Project Eden in some places. In most cases I’m unaffected, except when my avatar wanders too close to the edge of some terrifying drop. Then I become subject to vertigo.
If you’re looking at combating those queasy VES feelings, try playing the game in a window. Making the window smaller relative to the rest of your screen may help. If it is a first-person game, disabling any head-bob may also help. Additionally experiment with resolution. For some, more detailed and realistic graphics will help quell the queasiness, while others feel better if the view is lower-resolution or less realistic.