Investigating the Turning Table

In 1853, at the height of a Spiritualist craze for table-turning seances, in which participants seated around a table reported it moving, tilting or rotating under what they took to be a supernatural or unknown physical force, Faraday applied his own experimental method directly to the claim. He devised a simple mechanical apparatus using a stack of light boards connected by an indicator, designed so that any conscious or unconscious pressure participants exerted on the table would be visible and measurable separately from any genuinely independent motion of the table itself.

His results, published as Experimental Investigation of Table-Moving, showed clearly that the table's apparent movement was produced by small, unconscious muscular pressure from the sitters themselves, who typically pushed the table in the direction they expected or hoped it would move without being aware they were doing so, rather than by any external force. Faraday's investigation is remembered as one of the first rigorous experimental applications of the ideomotor effect, the phenomenon by which expectation produces small unconscious muscle movement, to a popular supernatural claim, conducted by a scientist whose own sincere religious faith makes his skepticism toward this specific Spiritualist practice a matter of applied method rather than general irreligion.