There are at least two good reasons for studying claims of paranormal phenomena. One is that the experiences are very common, and levels of belief are high. In a 1991 Gallup poll of over 1,000 Americans, a quarter claimed to have communicated with someone else by ESP, and half believed in ESP (Gallup and Newport, 1991). A repeat of the poll 10 years on provided similar results with 41 per cent believing in ESP, 31 per cent in telepathy and 26 per cent in clairvoyance. The 10 items included ghosts, channelling and astrology, and almost three quarters of Americans believed in at least one. In a British survey of more than 6,000 people, 59 per cent believed in ESP, with higher belief among women than men (Blackmore, 1997).