This could explain what most of these wahobes do in isolation!
History
In the 1930s, research by psychologist Wolfgang Metzger established that when subjects gazed into a featureless field of vision they consistently hallucinated and their electroencephalograms changed.
The Ganzfeld effect is the result of the brain amplifying neural noise in order to look for the missing visual signals. 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.
The Ganzfeld effect has been reported since ancient times. The adepts of Pythagoras retreated to pitch black caves to receive wisdom through their visions,[3] 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 effect is a component of a Ganzfeld experiment, a technique used in the field of parapsychology.
The artist James Turrell (partly inspired by clear blue skies) has created many such "Ganzfelds" throughout his oeuvre.