Ganzfeld

The Ganzfeld (literally "whole field" in German) refers to two related concepts in psychology and parapsychology. In perception research, the Ganzfeld effect describes the phenomenon that occurs when a person experiences uniform, unstructured sensory input, typically through a visual field of uniform color and white noise or pink noise at moderate volume. This homogeneous stimulation reduces external variability and can lead to unusual subjective experiences, such as intensified mental imagery, mild hallucination-like experiences, and altered time perception. The effect is studied to understand how the brain integrates sensory information and how attention can drift under low-stimulation conditions. Experimental setups commonly use a halved ping-pong ball or translucent dome over the eyes, soft diffuse lighting, and continuous noise to create a uniform field.

In parapsychology, the Ganzfeld experiment is a standardized protocol intended to test for extrasensory perception, especially telepathy. A sender views a target image or video while the receiver, in a quiet, soundproof room with uniform sensory input, attempts to describe or identify the target. The results have been controversial; some studies report modestly above-chance performance, but numerous replication failures and methodological criticisms have led to a cautious view of the evidence. Systematic reviews emphasize potential issues such as sensory leakage, experimental bias, and file-drawer effects, and note that overall findings do not constitute robust, reproducible evidence for psi.