^ LeCron, Leslie; Bordeaux, Jean (1970). Hypnotism Today. Wilshire Book Co. p. 278. ISBN 0-87980-081-X. When in a trance ... the medium seems to come under the control of another personality, purportedly the spirit of a departed soul, and a genuine medium undoubtedly believes the 'control' to be a spirit entity ... In the trance, the medium often enters a cataleptic state marked by extreme rigidity. The control then takes over, the voice may change completely ... and the supposed spirit answers the questions of the sitter, telling of things 'on the other plane' and gives messages from those who have 'passed over.'
Prominent investigators who exposed cases of fraud came from a variety of backgrounds, including professional researchers such as Frank Podmore of the Society for Psychical Research and Harry Price of the National Laboratory of Psychical Research, and professional conjurers such as John Nevil Maskelyne. Maskelyne exposed the Davenport brothers by appearing in the audience during their shows and explaining how the trick was done.
In English-speaking countries, where these games are not played, tarot cards are used primarily for divinatory purposes, usually using specially designed packs. The cards are traced by some occult writers to ancient Egypt or the Kabbalah but there is no documented evidence of such origins or of the usage of tarot for divination before the 18th century.
In 1991, Wendy Grossman in the New Scientist criticized the parapsychologist Stephen E. Braude for ignoring evidence of fraud in mediumship. According to Grossman "[Braude] accuses sceptics of ignoring the evidence he believes is solid, but himself ignores evidence that does not suit him. If a medium was caught cheating on some occasions, he says, the rest of that medium's phenomena were still genuine." Grossman came to the conclusion that Braude did not do proper research on the subject and should study "the art of conjuring."
In 1917, Edward Clodd analyzed the mediumship of the trance medium Gladys Osborne Leonard and came to the conclusion that Leonard had known her séance sitters before she had held the séances, and could have easily obtained such information by natural means. The British psychiatrist Charles Arthur Mercier wrote in his book Spiritualism and Sir Oliver Lodge (1917) that Oliver Lodge had been duped into believing mediumship by trickery and his spiritualist views were based on assumptions and not scientific evidence.
The exposures of fraudulent activity led to a rapid decline in ectoplasm and materialization séances. 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.