Parapsychologists and Spiritualists have an ongoing interest in EVP. Critical analysts, including some parapsychologists, are not satisfied with experimental parapsychology studies. Experimental investigation of the paranormal has been conducted by parapsychologists. Although Madison hires parapsychologists and psychics to investigate the haunting, none can help her. The Ownbey-Zirkle ESP experiment at Duke was criticized by parapsychologists and skeptics. Parapsychologists have reported experiments they use to test for telepathic abilities. Some parapsychologists criticized his work, suggesting the results were due to "his own telekinetic abilities". Due to the methodological problems, parapsychologists no longer utilize card-guessing studies. Because of the methodological problems, parapsychologists no longer utilize card-guessing studies. Lethbridge's work continued to attract interest from parapsychologists after his death. Of all nations the United Kingdom has the largest number of active parapsychologists. In 1957, the Parapsychological Association was formed as the preeminent society for parapsychologists.