A Ouija board (pronounced 'wee-ja' or 'wee-gee') is a board usually marked with the alphabet, numbers 0-9, 'yes', 'no' and 'goodbye'. Some people believe the Ouija board can be used to communicate with the spirit world through a planchette (small wooden piece) held by a person on the board, which then supposedly moves as a spirit relays a message. Talking boards have been traced back to ancient China, Greece and Rome. The Ouija board was first sold in the late 1890s as a parlour game before American Spiritualist Pearl Curran popularised it as an instrument to contact spirits during World War I. Many scientists believe Ouija boards can be explained by the ideo-motor response - the theory that a mental image can cause a reflexive or muscular reaction that the subject may not be conscious of.