James Randi

A dowser gives a demonstration of his professed powers and fails. Dowsing (also known as ‘divining’ and ‘water-witching’) is the claimed ability to locate water, oil, minerals, objects, locations, missing persons etc. using such objects as a metal rod, a pair of bent wires, a forked stick, a pendulum or the open hands. In controlled tests, dowsing fails every time. Dowsing is actually nothing more than an example of the ‘ideomotor effect’ – a known psychological phenomenon in which the dowser moves/tips the dowsing apparatus entirely unconsciously, giving the powerful illusion that the device moves of its own accord. This is also the explanation behind the ouija board and automatic writing. The effect is clearly visible in this video. At 1.48 you can actually see his hand shaking the rod from side to side. Since this is happening unconsciously, he isn’t aware he is doing it and so firmly believes that the rod is moving on its own. From episode 4 of ‘James Randi – Psychic Investigator’ (1991)