After her death in the 1980s the medium Doris Stokes was accused of fraud, by author and investigator Ian Wilson. Wilson stated that Mrs Stokes planted specific people in her audience and did prior research into her sitters. Rita Goold a physical medium during the 1980s was accused of fraud, by the psychical researcher Tony Cornell. He claimed she would dress up as the spirits in her séances and would play music during them which provided cover for her to change clothes.
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.
The séance trick of the Eddy Brothers was revealed by the magician Chung Ling Soo in 1898. The brothers utilized a fake hand made of lead, and with their hands free from control would play musical instruments and move objects in the séance room. The physiologist Ivor Lloyd Tuckett examined a case of spirit photography that W. T. Stead had claimed was genuine. Stead visited a photographer who had produced a photograph of him with deceased soldier known as "Piet Botha". Stead claimed that the photographer could not have come across any information about Piet Botha, however, Tuckett discovered that an article in 1899 had been published on Pietrus Botha in a weekly magazine with a portrait and personal details.
Ray Hyman discovered many methodological errors with Schwartz's research including; "Inappropriate control comparisons", "Failure to use double-blind procedures", "Creating non-falsifiable outcomes by reinterpreting failures as successes" and "Failure to independently check on facts the sitters endorsed as true". Hyman wrote "Even if the research program were not compromised by these defects, the claims being made would require replication by independent investigators." Hyman criticizes Schwartz's decision to publish his results without gathering "evidence for their hypothesis that would meet generally accepted scientific criteria... they have lost credibility."
Mina Crandon claimed to materialize a "spirit hand", but when examined by biologists the hand was discovered to be made from a piece of carved animal liver. The German apport medium Heinrich Melzer was discovered to be a fraud in 1926. In a séance psychical researchers found that Melzer had small stones attached to the back of his ears by flesh coloured tape. Psychical researchers who investigated the mediumship of Maria Silbert revealed that she used her feet and toes to move objects in the séance room.
The spirit photographer William Hope tricked William Crookes with a fake spirit photograph of his wife in 1906. Oliver Lodge revealed there had been obvious signs of double exposure, the picture of Lady Crookes had been copied from a wedding anniversary photograph, however, Crookes was a convinced spiritualist and claimed it was genuine evidence for spirit photography.
^ "Glossary of Key Words Frequently Used in Parapsychology" Archived 2010-12-24 at the Wayback Machine, Parapsychological Association website. "Materialization: A phenomenon of physical mediumship in which living entities or inanimate objects are caused to take form, sometimes from ectoplasm." Retrieved January 24, 2006 "Medium – Definition". Dictionary.com. Retrieved 23 March 2007.