But the real question, the one everyone wants to know, is how do Ouija boards work? Ouija boards are not, scientists say, powered by spirits or even demons. Disappointing but also potentially useful—because they’re powered by us, even when we protest that we’re not doing it, we swear. Ouija boards work on a principle known to those studying the mind for more than 160 years: the ideometer effect. In 1852, physician and physiologist William Benjamin Carpenter published a report for the Royal Institution of Great Britain, examining these automatic muscular movements that take place without the conscious will or volition of the individual (think crying in reaction to a sad film, for example). Almost immediately, other researchers saw applications of the ideometer effect in the popular spiritualist pastimes. In 1853, chemist and physicist Michael Faraday, intrigued by table-turning, conducted a series of experiments that proved to him (though not to most spiritualists) that the table’s motion was due to the ideomotor actions of the participants.