From Kook Science
The ganzfeld effect (German: ganzfeld, "complete field") is a perceptual phenomena resulting from partial sense deprivation from a homogeneous, non-patterned visual or audio (or both) stimulation, first experimentally explored by psychologist Wolfgang Metzger. The effect has been used extensively in the study of ESP.
Ganzfeld ESP experimentation
In an experimental setting, the subject is made to relax with halved ping-pong balls over their eyes and a red light shone over them (to produce a uniform field of color), while headphones play white or pink noise (to produce a non-patterned audio feedback), inducing a state of mild sense deprivation. The combination of an unchanging visual field and static audio feedback causes an amplification of "neural noise" as the brain attempts to locate novel sensory information, consistently producing hallucinations and other altered states.
For the purposes of ESP testing, the experiment subject, called a "receiver", is left in the state of sensory deprivation, while a "sender" attempts to psychically project target information to them. At the end of the sense deprivation session, the receiver is provided a set of possible targets (one of them being the target the sender projected), and selects based on the visuals they "saw" while in the ganzfeld state.
- Ganzfeld: Hack Your Brain the Legal Way, instructables.com, http://www.instructables.com/id/Ganzfeld-Hack-Your-Brain-the-Legal-Way/ — DIY instructions for reproducing the Ganzfeld effect.
- Metzger, Wolfgang (1930), "Optische Untersuchungen am Ganzfeld", Psychologische Forschung 13: 6-29