Spiritualists believe that phenomena produced by mediums (both mental and physical mediumship) are the result of external spirit agencies. The psychical researcher Thomson Jay Hudson in The Law of Psychic Phenomena (1892) and Théodore Flournoy in his book Spiritism and Psychology (1911) wrote that all kinds of mediumship could be explained by suggestion and telepathy from the medium and that there was no evidence for the spirit hypothesis. The idea of mediumship being explained by telepathy was later merged into the "super-ESP" hypothesis of mediumship which is currently advocated by some parapsychologists.
My stance on psychics hasn't really changed since then, but I also consider myself a fairly open-minded person and love having my views changed when enough solid evidence is presented to me. What if there really was something to psychics, but my mom had just chosen a bad one? What if she had just been asking the wrong questions? What if Malaysian psychics were just sketchy? So many people have turned to psychics for so long that there must be something to it all, right?
In 1876, William Eglinton was exposed as a fraud when the psychical researcher Thomas Colley seized a "spirit" materialization in his séance and cut off a portion of its cloak. It was discovered that the cut piece matched a cloth found in Eglinton's suitcase. Colley also pulled the beard off the materialization and it was revealed to be a fake, the same as another one found in the suitcase of Eglinton. In 1880 in a séance a spirit named "Yohlande" materialized, a sitter grabbed it and was revealed to be the medium Mme. d'Esperance herself.
^ 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.'
Many 19th century mediums were discovered to be engaged in fraud. While advocates of mediumship claim that their experiences are genuine, the Encyclopædia Britannica article on spiritualism notes in reference to a case in the 19th century that "...one by one, the Spiritualist mediums were discovered to be engaged in fraud, sometimes employing the techniques of stage magicians in their attempts to convince people of their clairvoyant powers." The article also notes that "the exposure of widespread fraud within the spiritualist movement severely damaged its reputation and pushed it to the fringes of society in the United States."