Attempts to communicate with the dead and other living human beings, aka spirits, have been documented back to early human history. The story of the Witch of Endor (In the most recent edition of the NIV witch is rendered medium in the passage) tells of one who raised the spirit of the deceased prophet Samuel to allow the Hebrew king Saul to question his former mentor about an upcoming battle, as related in the Books of Samuel in the Jewish Tanakh (the basis of the Old Testament).
In 1930 the Polish medium Stanisława P. was tested at the Institut Metapsychique in Paris. French psychical researcher Eugéne Osty suspected in the séance that Stanislawa had freed her hand from control. Secret flashlight photographs that were taken revealed that her hand was free and she had moved objects on the séance table. It was claimed by spiritualists that during a series of séances in 1930 the medium Eileen J. Garrett channeled secret information from the spirit of the Lieutenant Herbert Carmichael Irwin who had died in the R101 crash a few days before the séance. Researcher Melvin Harris who studied the case wrote that the information described in Garrett's séances were "either commonplace, easily absorbed bits and pieces, or plain gobblede-gook. The so-called secret information just doesn't exist."
The biblical basis of this practice is St. Paul's advice to his disciple Timothy whom he appointed bishop. St. Paul told him to "Attend to reading." The word "attend" an allusion to the many other concerns that a bishop has to attend to. By this, according to St. Alphonsus Liguori, Doctor of the Church on Moral theology, the Apostle Paul "wished him to apply to the reading of holy books, not in a passing way and for a short time, but regularly and for a considerable time."
The psychologist and psychical researcher Stanley LeFevre Krebs had exposed the Bangs Sisters as frauds. During a séance he employed a hidden mirror and caught them tampering with a letter in an envelope and writing a reply in it under the table which they would pretend a spirit had written. The British materialization medium Rosina Mary Showers was caught in many fraudulent séances throughout her career. In 1874 during a séance with Edward William Cox a sitter looked into the cabinet and seized the spirit, the headdress fell off and was revealed to be Showers.
Everyone knows the great influence that is exerted by the voice of a friend who gives candid advice, assists by his counsel, corrects, encourages and leads one away from error. Blessed is the man who has found a true friend; he that has found him has found a treasure. We should, then, count pious books among our true friends. They solemnly remind us of our duties and of the prescriptions of legitimate discipline; they arouse the heavenly voices that were stifled in our souls; they rid our resolutions of listlessness; they disturb our deceitful complacency; they show the true nature of less worthy affections to which we have sought to close our eyes; they bring to light the many dangers which beset the path of the imprudent. They render all these services with such kindly discretion that they prove themselves to be not only our friends, but the very best of friends. They are always at hand, constantly beside us to assist us in the needs of our souls; their voice is never harsh, their advice is never self-seeking, their words are never timid or deceitful.
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.