Skeptics have challenged the veracity of the claims of psychic readings, largely through disclosure of the methods. Psychologist Richard Wiseman's 2011 book Paranormality: Why We See What Isn't There noted the tricks of the trade, and Wiseman noted in a podcast appearance that the disclosure generated negative feedback from the psychic community.[24]
Probably the cheesiest and most parodied form of spiritual mediumship, physical mediums are the “agents” or “substrates” which spirits draw energy from and manipulate that energy into noises or displays to prove their existence and presence in the room. In the 19th century, physical mediums were very popular, though whether as parlor games or genuine spiritual interests you just can’t tell. Physical mediums at this time were often complete charlatans, with complicated secret knocking mechanisms and other tricks to prove the existence of spirits.

In the typical deep trance, the medium may not have clear recall of all the messages conveyed while in an altered state; such people generally work with an assistant. That person selectively wrote down or otherwise recorded the medium's words. Rarely did the assistant record the responding words of the sitter and other attendants. An example of this kind of relationship can be found in the early 20th century collaboration between the trance medium Mrs. Cecil M. Cook of the William T. Stead Memorial Center in Chicago (a religious body incorporated under the statutes of the State of Illinois) and the journalist Lloyd Kenyon Jones. The latter was a non-medium Spiritualist who transcribed Cook's messages in shorthand. He edited them for publication in book and pamphlet form.[25]

^ Paul Kurtz. (1985). A Skeptic's Handbook of Parapsychology. Prometheus Books. p. 29. ISBN 978-0-87975-300-9 "Florence Cook was caught cheating not only before her séances with Crookes but also afterward. Furthermore, she learned her trade from the mediums Frank Herne and Charles Williams, who were notorious for their cheating." Also see M. Lamar Keene. (1997). The Psychic Mafia. Prometheus Books. p. 64. ISBN 978-1-57392-161-9 "The most famous of materialization mediums, Florence Cook – though she managed to convince a scientist, Sir William Crookes, that she was genuine – was repeatedly exposed in fraud. Florence had been trained in the arts of the séance by Frank Herne, a well-known physical medium whose materializations were grabbed on more than one occasion and found to be the medium himself."
Mina Crandon (1888–1941), a spiritualist medium in the 1920s, was known for producing an ectoplasm hand during her séances. The hand was later exposed as a trick when biologists found it to be made from a piece of carved animal liver.[54] In 1934, the psychical researcher Walter Franklin Prince described the Crandon case as "the most ingenious, persistent, and fantastic complex of fraud in the history of psychic research."[55]
As soon as Thomas John set foot in the mbg office a few weeks ago, we knew he was the real deal. The skeptics among us walked away as converts, having communicated with their ancestors through Thomas in ways they never dreamed possible. Here, the highly sought-after medium and intuitive whose celebrity clientele includes Jennifer Lopez and Courteney Cox shares his top insights from the other side.

In 1970 two psychical researchers investigated the direct-voice medium Leslie Flint and found that all the "spirit" voices in his séance sounded exactly like himself and attributed his mediumship to "second-rate ventriloquism".[170] The medium Arthur Ford died leaving specific instructions that all of his files should be burned. In 1971 after his death, psychical researchers discovered his files but instead of burning them they were examined and discovered to be filled with obituaries, newspaper articles and other information, which enabled Ford to research his séance sitters backgrounds.[171]