In popular culture the wor psychic (pronounced /ˈsaɪkɨk/; from the Greek psychikos—"of the soul, mental") refers to the claimed ability to perceive things hidden from the senses through means of extra-sensory perception. The term also refers to theatrical performers who use techniques such as prestidigitation and cold reading to produce the appearance of having such abilities. Parapsychologists attempt to study what some believe are psychic phenomena using a variety of methods such as random number generators to test for psychokinesis or the Ganzfeld experiment to test for extra-sensory perception.