The psychological phenomenon of a person’s ideas creating in their body tiny muscular movements below their threshold of awareness. Just thinking about a certain physical action initiates minute reactions in the muscles which would be used in that action – these movements become magnified in a system under tension, such as in the inherent instability involved with the operation of an ouija board, dowsing rod, pendulum, tipping a table with the fingertips at a séance, etc.

This phenomenon will often be found very striking by those experiencing it (particularly for the first time), and especially if they are unaware of the underlying nature of events, so much so that, for example, when the ouija board is ‘consulted’ the participants may overlook the fact that no more information is ‘revealed’ by its supposed supernatural shenanigans than is known by those using it.

Once believers have experienced the ‘power’ of dowsing or the pendulum, etc., it may very difficult indeed to persuade them that what they have felt is the result of this well-known effect.

(see also: ESP (extra-sensory perception) » prophesy, Clairvoyant test, Cold Reading, expectation)