The spiritualists Arthur Conan Doyle and W. T. Stead were duped into believing Julius and Agnes Zancig had genuine psychic powers. Both Doyle and Stead wrote that the Zancigs performed telepathy. In 1924 Julius and Agnes Zancig confessed that their mind reading act was a trick and published the secret code and all the details of the trick method they had used under the title of Our Secrets!! in a London Newspaper.[144]

"Mental mediumship" is communication of spirits with a medium by telepathy. The medium mentally "hears" (clairaudience), "sees" (clairvoyance), and/or feels (clairsentience) messages from spirits. Directly or with the help of a spirit guide, the medium passes the information on to the message's recipient(s). When a medium is doing a "reading" for a particular person, that person is known as the "sitter".
The exposures of fraudulent activity led to a rapid decline in ectoplasm and materialization séances.[202] Investigator Joe Nickell has written that modern self-proclaimed mediums like John Edward, Sylvia Browne, Rosemary Altea and James Van Praagh are avoiding the Victorian tradition of dark rooms, spirit handwriting and flying tambourines as these methods risk exposure. They instead use "mental mediumship" tactics like cold reading or gleaning information from sitters before hand (hot reading). Group readings also improve hits by making general statements with conviction, which will fit at least one person in the audience. Shows are carefully edited before airing to show only what appears to be hits and removing anything that does not reflect well on the medium.[203]

On Fox News on the Geraldo at Large show, October 6, 2007, Geraldo Rivera and other investigators accused Schwartz as a fraud as he had overstepped his position as a university researcher by requesting over three million dollars from a bereaved father who had lost his son. Schwartz claimed to have contacted the spirit of a 25-year-old man in the bathroom of his parents house and it is alleged he attempted to charge the family 3.5 million dollars for his mediumship services. Schwartz responded saying that the allegations were set up to destroy his science credibility.[197][198]
Modern spiritualists and psychics keep detailed files on their victims. As might be expected, these files can be very valuable and are often passed on from one medium or psychic to another when one retires or dies. Even if a psychic doesn't use a private detective or have immediate access to driver's license records and such, there is still a very powerful technique that will allow the psychic to convince people that the psychic knows all about them, their problems, and their deep personal secrets, fears, and desires. The technique is called cold reading and is probably as old as charlatanism itself... If John Edward (or any of the other self-proclaimed speakers with the dead) really could communicate with the dead, it would be a trivial matter to prove it. All that would be necessary would be for him to contact any of the thousands of missing persons who are presumed dead—famous (e.g., Jimmy Hoffa, Judge Crater) or otherwise—and correctly report where the body is. Of course, this is never done. All we get, instead, are platitudes to the effect that Aunt Millie, who liked green plates, is happy on the other side.[195]
The Polish medium Stanisława Tomczyk's levitation of a glass beaker was exposed and replicated in 1910 by the magician William S. Marriott by means of a hidden thread.[117] The Italian medium Lucia Sordi was exposed in 1911, she was bound to a chair by psychical researchers but would free herself during her séances. The tricks of another Italian medium Linda Gazzera were revealed in the same year, she would release her hands and feet from control in her séances and use them. Gazzera would not permit anyone to search her before a séance sitting, as she concealed muslin and other objects in her hair.[118]

Español: ser un médium psíquico, Português: Se Tornar um Médium, Italiano: Diventare un Medium, Français: devenir un médium, Русский: стать экстрасенсом–медиумом, Deutsch: Ein hellseherisches Medium werden, Nederlands: Helderziende worden, 中文: 成为灵媒, Čeština: Jak se stát médiem, Bahasa Indonesia: Menjadi Medium Psikis, हिन्दी: मनोवैज्ञानिक माध्यम बनें, العربية: أن تكون وسيطًا روحيًا
In 1954, the psychical researcher Rudolf Lambert published a report revealing details about a case of fraud that was covered up by many early members of the Institute Metapsychique International (IMI).[166] Lambert who had studied Gustav Geley's files on the medium Eva Carrière discovered photographs depicting fraudulent ectoplasm taken by her companion Juliette Bisson.[166] Various "materializations" were artificially attached to Eva's hair by wires. The discovery was never published by Geley. Eugéne Osty (the director of the institute) and members Jean Meyer, Albert von Schrenck-Notzing and Charles Richet all knew about the fraudulent photographs but were firm believers in mediumship phenomena so demanded the scandal be kept secret.[166]

In 1910 at a séance in Grenoble, France the apport medium Charles Bailey produced two live birds in the séance room. Bailey was unaware that the dealer he had bought the birds from was present in the séance and he was exposed as a fraud.[114] The psychical researcher Eric Dingwall observed the medium Bert Reese in New York and claimed to have discovered his billet reading tricks.[115] The most detailed account at exposing his tricks (with diagrams) was by the magician Theodore Annemann.[116]
In the late 1920s and early 1930s there were around one quarter of a million practising Spiritualists and some two thousand Spiritualist societies in the UK in addition to flourishing microcultures of platform mediumship and 'home circles'.[18] Spiritualism continues to be practised, primarily through various denominational Spiritualist churches in the United States, Canada, Australia and the United Kingdom. In the United Kingdom, over 340 Spiritualist churches and centres open their doors to the public and free demonstrations of mediumship are regularly performed.[19]