An experiment conducted by the British Psychological Society in 2005 suggests that under the controlled condition of the experiment, people who claimed to be professional mediums do not demonstrate the mediumistic ability. In the experiment, mediums were assigned to work the participants chosen to be "sitters." The mediums claimed to contact the deceased who were related to the sitters. The research gather the numbers of the statements made and have the sitters rate the accuracy of the statements. The readings that were considered to be somewhat accurate by the sitters were very generalized, and the ones that were considered inaccurate were the ones that were very specific.
For the less experienced mediums, exactly the opposite was observed--increased levels of activity in the same frontal areas during psychography compared to normal writing, and the difference was significant compared to the experienced mediums. What this probably means is that the less experienced mediums were trying really hard. The force is not yet strong with them.
In September 1878 the British medium Charles Williams and his fellow-medium at the time, A. Rita, were detected in trickery at Amsterdam. During the séance a materialized spirit was seized and found to be Rita and a bottle of phosphorus oil, muslin and a false beard were found amongst the two mediums. In 1882 C. E. Wood was exposed in a séance in Peterborough. Her Indian spirit control "Pocka" was found to be the medium on her knees, covered in muslin.