German for “total held”; a test for psi (parapsychological) communication that attempts to neutralize all known possibilities of sense perception of a mentally transmitted target. Pioneered in psychology by Herman Witkin, the ganzfeld was modified for parapsychological use and introduced to that held by Charles Honorton and William Braud in their 1974 and 1975 studies, respectively.
The standard ganzfeld procedure involves one or several experimenters, who instruct and monitor the subjects, and a sender-and-receiver pair, each of whom is sequestered in a soundproof room. The sender is shown, either tachistoscopically or continually, pictures or him sequences to be communicated mentally to the receiver, who is in a nearby and separate room. The receiver is in a near-total state of sense deprivation, as white or pink noise (a loud hissing which blocks out other sounds) is broadcast to him or her through heavily padded headphones. The receiver’s eyes are covered with Ping-Pong ball halves, which fill his or her held of vision with only uniform white or red light, cast from a lamp or lamps about four meters distant.