The article about this phenomenon in Encyclopædia Britannica places emphasis that "… one by one spiritual mediums were convicted of fraud, sometimes using the tricks borrowed from scenic "magicians" to convince their paranormal abilities". In the article it is also noted that "… the opening of the wide ranging fraud happening on spiritualistic sessions caused serious damage to reputation of the movement of a Spiritualism and in the USA pushed it on the public periphery". https://drive.google.com/file/d/1y5Nf16dWP74wWod3tdEZ2TTw0KpVA-UP/view?usp=sharing
Illusionists, such as Joseph Rinn have staged fake séances in which the sitters have claimed to have observed genuine supernatural phenomena. Albert Moll studied the psychology of séance sitters. According to (Wolffram, 2012) "[Moll] argued that the hypnotic atmosphere of the darkened séance room and the suggestive effect of the experimenters' social and scientific prestige could be used to explain why seemingly rational people vouchsafed occult phenomena." The psychologists Leonard Zusne and Warren Jones in their book Anomalistic Psychology: A Study of Magical Thinking (1989) wrote that spirits controls are the "products of the medium's own psychological dynamics."
^ "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.