Senses used by mental mediums are sometimes defined differently from in other paranormal fields. A medium is said to have psychic abilities but not all psychics function as mediums. The term clairvoyance, for instance, may include seeing spirit and visions instilled by the spirit world. The Parapsychological Association defines "clairvoyance" as information derived directly from an external physical source.[37]

In the 1920s the British medium Charles Albert Beare duped the Spiritualist organization the Temple of Light into believing he had genuine mediumship powers. In 1931 Beare published a confession in the newspaper Daily Express. In the confession he stated "I have deceived hundreds of people…. I have been guilty of fraud and deception in spiritualistic practices by pretending that I was controlled by a spirit guide…. I am frankly and whole-heartedly sorry that I have allowed myself to deceive people."[124] Due to the exposure of William Hope and other fraudulent spiritualists, Arthur Conan Doyle in the 1920s led a mass resignation of eighty-four members of the Society for Psychical Research, as they believed the Society was opposed to spiritualism.[125]
Humans have been fascinated with contacting the dead since the beginning of human existence. Cave paintings by indigenous Australians date back 28,000 years, some depicting skulls, bones, spirits and the afterlife.[3] Other cave paintings in Indonesia date back a further 10,000 years.[4] Mediumship gained popularity during the nineteenth century, when ouija boards were used by the upper classes as a source of entertainment. Investigations during this period revealed widespread fraud—with some practitioners employing techniques used by stage magicians—and the practice began to lose credibility.[5][6] Fraud is still rife in the medium/psychic industry, with cases of deception and trickery being discovered to this day.[7]