thumb|right|The [[Ganzfeld experiments that aimed to demonstrate telepathy have been criticized for lack of replication and poor controls.]]
Telepathy () is the purported vicarious transmission of information from one person's mind to another's without using any known human sensory channels or physical interaction. The term was first coined in 1882 by the classical scholar Frederic W. H. Myers, a founder of the Society for Psychical Research (SPR), and has remained more popular than the earlier expression thought-transference.
Telepathy experiments have historically been criticized for a lack of proper controls and repeatability. There is no good evidence that telepathy exists, and the topic is generally considered by the scientific community to be pseudoscience. Telepathy is a common theme in science fiction.
Origins of the concept
According to historians such as Roger Luckhurst and Janet Oppenheim the origin of the concept of telepathy in Western civilization can be traced to the late 19th century and the formation of the Society for Psychical Research. As the physical sciences made significant advances, scientific concepts were applied to mental phenomena (e.g., animal magnetism), with the hope that this would help to understand paranormal phenomena. The modern concept of telepathy emerged in this context.
Thought reading
In the late 19th century, the magician and mentalist Washington Irving Bishop would perform "thought reading" demonstrations. Bishop claimed no supernatural powers and ascribed his powers to muscular sensitivity (reading thoughts from unconscious bodily cues). Bishop was investigated by a group of scientists including the editor of the British Medical Journal and the psychologist Francis Galton. Bishop performed several feats successfully, such as correctly identifying a selected spot on a table and locating a hidden object. During the experiment, Bishop required physical contact with a subject who knew the correct answer. He would hold the hand or wrist of the helper. The scientists concluded that Bishop was not a genuine telepath but was instead using a highly trained skill to detect ideomotor movements.
Another famous thought reader was the magician Stuart Cumberland. He was famous for performing blindfolded feats such as identifying a hidden object in a room that a person had picked out or asking someone to imagine a murder scene and then attempt to read the subject's thoughts and identify the victim and reenact the crime. Cumberland claimed to possess no genuine psychic ability and his thought-reading performances could only be demonstrated by holding the hand of his subject to read their muscular movements. He came into dispute with psychical researchers associated with the Society for Psychical Research who were searching for genuine cases of telepathy. Cumberland argued that both telepathy and communication with the dead were impossible and that the minds of people cannot be read through telepathy, but only by muscle reading.
Case studies
thumb|[[Gilbert Murray conducted early telepathy experiments.]]
In the late 19th century the Creery Sisters (Mary, Alice, Maud, Kathleen, and Emily) were tested by the Society for Psychical Research and believed to have genuine psychic ability. However, during a later experiment they were caught utilizing signal codes and they confessed to fraud. George Albert Smith and Douglas Blackburn were claimed to be genuine psychics by the Society for Psychical Research but Blackburn confessed to fraud:
<blockquote>For nearly thirty years the telepathic experiments conducted by Mr. G. A. Smith and myself have been accepted and cited as the basic evidence of the truth of thought transference...
...the whole of those alleged experiments were bogus, and originated in the honest desire of two youths to show how easily men of scientific mind and training could be deceived when seeking for evidence in support of a theory they were wishful to establish.</blockquote>
Between 1916 and 1924, Gilbert Murray conducted 236 experiments into telepathy and reported 36% as successful. However, it was suggested that the results could be explained by hyperaesthesia as he could hear what was being said by the sender. Psychologist Leonard T. Troland had carried out experiments in telepathy at Harvard University which were reported in 1917. The subjects produced below chance expectations.
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.
In 1924, Robert H. Gault of Northwestern University with Gardner Murphy conducted the first American radio test for telepathy. The results were entirely negative. One of their experiments involved the attempted thought transmission of a chosen number between one and one-thousand. Out of 2,010 replies, none was correct. This is below the theoretical chance figure of two correct replies in such a situation.
In February 1927, with the co-operation of the British Broadcasting Corporation (BBC), V. J. Woolley, who was at the time the Research Officer for the SPR, arranged a telepathy experiment in which radio listeners were asked to take part. The experiment involved 'agents' thinking about five selected objects in an office at Tavistock Square, whilst listeners on the radio were asked to identify the objects from the BBC studio at Savoy Hill. 24,659 answers were received. The results revealed no evidence of telepathy.
A famous experiment in telepathy was recorded by the American author Upton Sinclair in his book Mental Radio which documents Sinclair's test of psychic abilities of Mary Craig Sinclair, his second wife. She attempted to duplicate 290 pictures which were drawn by her husband. Sinclair claimed Mary successfully duplicated 65 of them, with 155 "partial successes" and 70 failures. However, these experiments were not conducted in a controlled scientific laboratory environment. Science writer Martin Gardner suggested that the possibility of sensory leakage during the experiment had not been ruled out: