The psychical researchers W. W. Baggally and Everard Feilding exposed the British materialization medium Christopher Chambers as a fraud in 1905. A false moustache was discovered in the séance room which he used to fabricate the spirit materializations. The British medium Charles Eldred was exposed as a fraud in 1906. Eldred would sit in a chair in a curtained off area in the room known as a "séance cabinet". Various spirit figures would emerge from the cabinet and move around the séance room, however, it was discovered that the chair had a secret compartment that contained beards, cloths, masks, and wigs that Eldred would dress up in to fake the spirits. https://drive.google.com/file/d/124oBBEPOkBnezwDgNdARlFAV-ArJQIaI/view?usp=sharing
In 1958, the English-born Spiritualist C. Dorreen Phillips wrote of her experiences with a medium at Camp Chesterfield, Indiana: "In Rev. James Laughton's séances there are many Indians. They are very noisy and appear to have great power. [...] The little guides, or doorkeepers, are usually Indian boys and girls [who act] as messengers who help to locate the spirit friends who wish to speak with you."
In 1930 the Polish medium Stanisława P. was tested at the Institut Metapsychique in Paris. French psychical researcher Eugéne Osty suspected in the séance that Stanislawa had freed her hand from control. Secret flashlight photographs that were taken revealed that her hand was free and she had moved objects on the séance table. It was claimed by spiritualists that during a series of séances in 1930 the medium Eileen J. Garrett channeled secret information from the spirit of the Lieutenant Herbert Carmichael Irwin who had died in the R101 crash a few days before the séance. Researcher Melvin Harris who studied the case wrote that the information described in Garrett's séances were "either commonplace, easily absorbed bits and pieces, or plain gobblede-gook. The so-called secret information just doesn't exist."
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.