Scientists who study anomalistic psychology consider mediumship to be the result of fraud and psychological factors. Research from psychology for over a hundred years suggests that where there is not fraud, mediumship and Spiritualist practices can be explained by hypnotism, magical thinking and suggestion. Trance mediumship, which according to Spiritualists is caused by discarnate spirits speaking through the medium, can be explained by dissociative identity disorder.
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.
A series of mediumistic séances known as the Scole Experiment took place between 1993 and 1998 in the presence of the researchers David Fontana, Arthur Ellison and Montague Keen. This has produced photographs, audio recordings and physical objects which appeared in the dark séance room (known as apports). A criticism of the experiment was that it was flawed because it did not rule out the possibility of fraud. The skeptical investigator Brian Dunning wrote the Scole experiments fail in many ways. The séances were held in the basement of two of the mediums, only total darkness was allowed with no night vision apparatus as it might "frighten the spirits away". The box containing the film was not examined and could easily have been accessible to fraud. And finally, even though many years have passed, there has been no follow-up, no further research by any credible agency or published accounts. https://drive.google.com/file/d/1RI-NfCL7IeA8g5u5CG-LtcFl76Secb11/view?usp=sharing
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'. 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.