Carpenter, Chevreul, and Faraday's Table

Michel-Eugene Chevreul, a French chemist, first described the phenomenon in a letter published in 1833, after investigating why a pendulum held perfectly still by a person's hand would nonetheless swing in the direction the holder expected it to, even when the holder was convinced they were exerting no force at all. Chevreul demonstrated that blindfolding the holder, or hiding the pendulum's target from view, stopped the movement, showing that the swing depended on the holder's expectation rather than on any property of the pendulum or its target; he published a fuller account of the finding, extending it to divining rods and table turning, in 1854.

William Benjamin Carpenter, an English physiologist, proposed the general theoretical name for the underlying mechanism in an 1852 lecture to the Royal Institution, terming it ideo-motor action: the principle that holding an idea of a movement in mind, even without conscious intention to act on it, tends to produce a small muscular movement toward carrying it out. Michael Faraday put the theory to a direct experimental test the following year, building an apparatus of card and rubber bands that would visibly indicate whether a sitter's hands were pushing a table or being pushed by it, and found consistently that the hands moved first.