In kokkuri-san, people put their fingers on a coin, and the coin seems to move by itself. Is it a ghost? No. The players' own fingers move it a little, but they do not notice.

In 1853, a scientist named Faraday showed that people's hands moved before a table moved. In a 2012 study, these hidden finger movements even seemed to show answers that people did not know they knew.

In the Japanese game kokkuri-san, or on a Western Ouija board, players lightly touch a coin or pointer, and it seems to move on its own. The real cause is ideomotor action. When we think about a movement, our muscles make tiny movements without our awareness. In 1853, the scientist Michael Faraday placed a device between people's hands and a table and showed that their hands moved first.

When people could see the device, the table hardly moved. In 2012, researchers in Canada tested blindfolded players who believed a partner was helping, though they were actually moving the board alone. For questions they felt they were only guessing, they answered correctly about 50% of the time by speaking but about 65% by using the board.

In 1853, Michael Faraday slipped a simple indicator between the hands of table-turners and the table they claimed was moving on its own. Table-turning was the nineteenth-century craze from which Japan's kokkuri-san descends. The indicator showed that the hands moved first and the table followed. Once participants could watch it, the table barely moved at all. When a person expects a movement, the muscles may start to carry it out on a scale too small to notice.

The physiologist Carpenter called this ideomotor action. The same force pushes the coin in kokkuri-san and the planchette on a Ouija board. A 2012 Canadian experiment, though based on a small group of volunteers, went further. Blindfolded participants answered yes-or-no questions on a Ouija board, believing that a partner shared the planchette, although the partner had quietly let go.

On questions where they felt they were only guessing, they were right about 50% of the time when they answered aloud but about 65% of the time with the board. So these tiny movements may carry knowledge that people do not know they have. A Danish eye-tracking study found that during "spirit" sessions, players looked ahead to the next letter less often.