Since the 19th century, the Ouija board has been viewed as both a dangerous instrument of the occult and a kitschy game to break out at parties. To use it, a group of people must place their fingers on the pointer, or planchette, and watch as the "spirits” glide it over the letters and numbers on the board, effectively spelling out their message. Some attribute this phenomenon to supernatural forces, while others point to deceptive pranksters. The real answer, however, is as spooky as it is scientific.

The ideomotor effect occurs when someone moves themself or an object without being conscious of their actions. This combined with a strong subconscious need for an answer, like what one might feel when using a Ouija board, leads to players moving the planchette without any knowledge of doing so.

A 2012 study from the University of British Columbia investigated this effect by having test subjects answer factual yes or no questions both verbally and with a Ouija board. For the Ouija board portion of the experiment, participants were blindfolded and told they’d be answering with another person, but when the experiment began their partner quickly removed their hands from the planchette. For questions they were unsure about, participants using the Ouija answered correctly 65 percent of the time compared to just 50 percent of the time when responding verbally.

The results of the study suggest people have a "second intelligence" buried in their subconscious mind that can only be accessed under the right conditions. "Ask someone ...'What's the capital of Cambodia?' and they might say, 'I have no idea,'" said Docky Duncan, one of the researchers from UBC's Visual Cognition Lab who furthered their research on the subject in 2014. "But they might have heard it somewhere, and it may actually be inside your brain."

The fact that Ouija board games are more of a psychological experiment than a communion with the dead makes them no less creepy. Feel free to share this scientific tidbit at your next impromptu seance, or keep it to yourself and use the knowledge to extract secrets from the minds of your friends.

[h/t: Nerdist]