A psychic is a person who claims to use extrasensory perception (ESP) to identify information hidden from the normal senses, or to manipulate objects mentally in a process known as psychokinesis. The word "psychic" is also used as an adjective to describe such abilities. Psychics may be theatrical performers, such as stage magicians, who use techniques such as prestidigitation, cold reading, and hot reading to produce the appearance of such abilities. Psychics appear regularly in fantasy fiction, such as in the novel The Dead Zone by Stephen King.
A large industry and network exists whereby psychics provide advice and counsel to clients. Some famous psychics include Edgar Cayce, Ingo Swann, Peter Hurkos, Jose Ortiz El Samaritano, Miss Cleo, John Edward, and Sylvia Browne. Psychic powers are asserted by psychic detectives and in practices such as psychic archaeology and even psychic surgery.
Critics attribute psychic powers to intentional trickery or to self-delusion. In 1988 the U.S. National Academy of Sciences gave a report on the subject and concluded there is "no scientific justification from research conducted over a period of 130 years for the existence of parapsychological phenomena." A study attempted to repeat recently reported parapsychological experiments that appeared to support the existence of precognition. Attempts to repeat the results, which involved performance on a memory test to ascertain if post-test information would effect it, "failed to produce significant effects", and thus "do not support the existence of psychic ability."