Colin Fry was exposed in 1992 when during a séance the lights were unexpectedly turned on and he was seen holding a spirit trumpet in the air, which the audience had been led to believe was being levitated by spiritual energy.[186] In 1997, Massimo Polidoro and Luigi Garlaschelli produced wax-moulds directly from one's hand which were exactly the same copies as Gustav Geley obtained from Franek Kluski, which are kept at the Institute Metapsychique International.[187]

The medium Frank Decker was exposed as a fraud in 1932. A magician and séance sitter who called himself M. Taylor presented a mail bag and Decker agreed to lock himself inside it. During the séance objects were moved around the room and it was claimed spirits had released Decker from the bag. It was later discovered to have been a trick as Martin Sunshine, a magic dealer admitted that he sold Decker a trick mail bag, such as stage escapologists use, and had acted as the medium's confederate by pretending to be M. Taylor, a magician.[158] The British medium Estelle Roberts claimed to materialize an Indian spirit guide called "Red Cloud". Researcher Melvin Harris who examined some photographs of Red Cloud wrote the face was the same as Roberts and she had dressed up in a feathered war-bonnet.[159]

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]
Michael Shermer criticized mediums in Scientific American, saying, "mediums are unethical and dangerous: they prey on the emotions of the grieving. As grief counselors know, death is best faced head-on as a part of life." Shermer wrote that the human urge to seek connections between events that may form patterns meaningful for survival is a function of natural evolution, and called the alleged ability of mediums to talk to the dead "a well-known illusion of a meaningful pattern."[204]
In the later half of the 20th century, Western mediumship developed in two different ways. One type involved clairaudience or sensitives who hear spirit, and then relay what they hear to their clients.[29] The other incarnation of non-physical mediumship is a form of channeling in which the channeler goes into a trance, or "leaves their body", allowing a spirit entity to borrow their body, who then speaks through them.[30] When in a trance the medium appears to come under the control of the spirit of a departed soul, sometimes entering into a cataleptic state,[31] although modern channelers may not.[citation needed] Some channelers open the eyes when channeling, and remain able to walk and behave normally. The rhythm and the intonation of the voice may also change completely.

According to the magician John Booth the stage mentalist David Devant managed to fool a number of people into believing he had genuine psychic ability who did not realize that his feats were magic tricks. At St. George's Hall, London he performed a fake "clairvoyant" act where he would read a message sealed inside an envelope. The spiritualist Oliver Lodge who was present in the audience was duped by the trick and claimed that Devant had used psychic powers. In 1936 Devant in his book Secrets of My Magic revealed the trick method he had used.[162]
"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".

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]