Although we talk about a few historical early forms of virtual reality elsewhere on the site today virtual reality is usually implemented using computer technology. There are a range of systems that are used for this purpose such as headsets omni-directional treadmills and special gloves. These are used to actually stimulate our senses together in order to create the illusion of reality.

This is more difficult than it sounds since our senses and brains are evolved to provide us with a finely synchronized and mediated experience. If anything is even a little off we can usually tell. This is where you’ll hear terms such asimmersiveness  and realism enter the conversation. These issues that divide convincing or enjoyable virtual reality experiences from jarring or unpleasant ones are partly technical and partly conceptual. Virtual reality technology needs to take our physiology into account. For example the human visual field does not look like a video frame. We have (more or less) 180 degrees of vision and although you are not always consciously aware of your peripheral vision if it were gone you’d notice. Similarly when what your eyes and the vestibular system in your ears tell you are in conflict it can cause motion sickness. Which is what happens to some people on boats or when they read while in a car.

If an implementation of virtual reality manages to get the combination of hardware software and sensory synchronicity just right it achieves something known as a sense of presence. Where the subject really feels like they are present in that environment.