In the 1930s, the result of German psychologist Wolfgang Metzger's experiment showed that when a subject's sight was filled with everything of the same color and having no differentiating properties, there would be changes to his encephalogram, and he might even suffer from hallucinations. The most common example would be miners who were trapped in darkness from cave ins. After a few days, they would start to hallucinate. Even explorers of the north pole would start seeing things after being exposed to pure whiteness for days. This was called the Ganzfeld Effect.
In 1974, psychologist Charles Honorton released the first experimental report on ESP in the periodical APA. From 1974 to 1982, forty-two ESP experiments were reported.
