It has been most studied with vision by staring at an undifferentiated and uniform field of colour. The visual effect is described as the loss of vision as the brain cuts off the unchanging signal from the eyes. The result is "seeing black" - apparent blindness. It can also elicit hallucinatory percepts in many people, in addition to an altered state of consciousness.
Ganzfeld induction in multiple senses is called multi-modal ganzfeld. This is usually done by wearing ganzfeld goggles in addition to headphones with a uniform stimuli.
A related effect is sensory deprivation. With sensory deprivation, however, a stimulus is minimized rather than unstructured. Ganzfeld is thus perceptual deprivation. Hallucinations that appear under prolonged sensory deprivation are similar to elementary percepts caused by luminous ganzfeld, these include transient sensations of light flashes or colours. Hallucinations caused by sensory deprivation can, like ganzfeld-induced hallucinations, turn into complex scenes.
The Ganzfeld effect is the according to whom?]. The noise is interpreted in the higher visual cortex, and gives rise to hallucinations. This may occur as a result of the sensory deprivation of sleep to produce dreams or in a loss of vision due to a traumatic event, such as would lead to the sights reported in near death experiences[speculation?].[
The Ganzfeld effect has been reported since ancient times. The adepts of Pythagoras retreated to pitch black caves to receive wisdom through their visions, known as the prisoner's cinema. Miners trapped by accidents in mines frequently reported hallucinations, visions and seeing ghosts when they were in the pitch dark for days. Arctic explorers seeing nothing but featureless landscape of white snow for a long time also reported hallucinations and an altered state of mind. 
The artist James Turrell (partly inspired by clear blue skies) has created many such "Ganzfelds" throughout his oeuvre.
See also 
- Sensory deprivation
- Ganzfeld experiment
- Dark retreat
- Floatation tank
- Charles Bonnet syndrome
- Third Man factor
- Wolfgang Metzger, "Optische Untersuchungen am Ganzfeld." Psychologische Forschung 13 (1930) : 6-29. (the first psychophysiological study with regard to Ganzfelds)
- Ramesh B. Ganzfeld Effect.
- Wackermann, Jirˇı´ (2008). "Ganzfeld-induced hallucinatory experience, its phenomenology and cerebral electrophysiology". Cortex 44 (2008) 1364 – 1378. Elsevier.
- Ustinova, Yulia.Caves and the Ancient Greek Mind: Descending Underground in the Search for Ultimate Truth, Oxford University Press US, 2009. ISBN 0-19-954856-0
- Geiger, John (2009). The Third Man Factor. Toronto: Viking Canada. ISBN 0-14-301751-9.
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