A Perception Experiment Repurposed for Psi

The ganzfeld, German for "whole field," was not invented for psi research at all. Perceptual psychologist Wolfgang Metzger developed it in the 1930s to study how the visual system behaves when given a completely uniform, featureless field to look at, typically achieved today with translucent halved ping-pong balls taped over closed eyes under red light, paired with white or pink noise piped through headphones.

Parapsychologist Charles Honorton adapted the setup in the early 1970s on the theory that reducing ordinary sensory input might make a subject more receptive to a faint telepathic signal, the same logic behind older "quiet room" and hypnagogic-state ESP experiments. In the standard ganzfeld trial, a "receiver" sits in the mildly deprived state for roughly half an hour while, in a separate isolated room, a "sender" concentrates on one randomly selected image or video clip out of a set the receiver has not seen; afterward the receiver is shown that same small set of possible targets and asked to identify which one the sender was viewing, giving a baseline chance hit rate of about twenty five percent with four choices. Honorton and his collaborators ran and compiled dozens of such studies through the late 1970s and early 1980s, reporting a pooled hit rate consistently above that chance baseline.