Depending on who you ask, Ouija boards are either an excellent way to communicate with the dead or an effective way to freak out your friends. Commercialized and popularized at the end of the 19th century, Ouija boards require two or more people to place their hands lightly on top of a triangular planchette and ask the board a question. The answer emerges from the letters, words, and numbers printed on the board. How the board “answers” is explained in a new study in Phenomenology and the Cognitive Sciences.

Marc Anderson, Ph.D., a postdoctoral researcher at Aarhus University in Denmark, believes that he and his team have figured out how the spooky toy works. At the heart of Ouija, he tells Inverse, lies a paradox: If you scratch out the possibility of the paranormal, you’re left with a group of people who are producing the responses themselves. Yet most participants, whether or not they believe they can communicate with spirits, are unable to predict what responses emerge. In their study, Anderson and his team discovered that the disparity depends on two of the brain’s innate qualities: a sense of agency and a love of prediction.

Anderson and his team came to this conclusion after going to Ouijacon, a three-day conference in Baltimore (“to research, preserve, and celebrate the history of talking boards”). While they were there, the scientists recruited 40 people from the conference and asked them to play two consecutive games on the Ouija board. The participants, which included skeptics and believers, wore eye-tracking devices during both games. In the first game, they were asked to simply spell the word “Baltimore” — a nod to the location of the conference. In the second, they were told to ask the board whatever they wanted.

The study's setting. Marc Andersen

After the games, each player was asked whether they experienced a sense of agency during the game; how much they felt a push from the other player; how much they pushed the planchette; and whether they believed they did — or even could — encounter a supernatural entity.

Going back through their data, the authors observed that in the first set of games, participants’ eyes would flick from letter to letter as they spelled out “Baltimore.” But in the game without a prompt, participants had a 21.3 percent lower chance of predicting what letter to look at. However, as a word began to form, people’s eyes would start to look predictively at the next letter. That’s because, whether or not a person is conscious of it, the mind likes to predict and impose structure on events.

“While early letters in a meaningful Ouija board response appear to occur at random, meaningful word options available to the participant decrease as the response from the Ouija board unfolds,” the scientists write. “This, in turn, makes it easier for a part of participants to collectively predict, and unconsciously construct, the responses from the Ouija board.”

The mind predicts the words that emerge on a Ouija board. Giphy

The interviews revealed that individuals who believed Ouija boards could contact supernatural beings were more likely to think the planchette moved on its own and that neither they nor the other participants pushed it. Doubting participants who believed the planchette was driven by subconscious thoughts felt differently: They thought that the other participant moved the planchette and, to a lesser degree, that they might have pushed it too without realizing.

“The participants feel as if they are not pushing the planchette precisely because they cannot visually predict where the planchette is going,” explains Andersen. “We know from cognitive neuroscience that the brain creates the feeling of control by predicting the sensory consequences of an action, and then compares this prediction to the actual consequences. If we cannot predict the sensory consequences of our own actions, we feel a loss of control.”

That loss of control was most felt by the participants who believed in the supernatural, while the other participants reported they felt a higher sense of agency in their lives. Both groups, however, demonstrated the ideomotor effect while they played. This phenomenon describes the way a sensory stimulus can unconsciously initiate physical action, even though participants may have felt a loss of conscious control.

Ouija, the "mystifying oracle." Giphy

Jay Olson, Ph.D., a postdoctoral researcher who was not involved with the study but has also examined the relationship between ideomotor actions and Ouija boards, tells Inverse this new research adds two important contributions to the study of one’s agency.

“First, it finds correlations between people’s sense of agency (feeling of control) over their movements and the perceived mechanism behind the movement (spirits vs. the unconscious),” Olson tells Inverse. “Second, it is to my knowledge the first study explore how people predict upcoming responses when jointly using a Ouija board.”

But Olson also points out other research has demonstrated that a distorted sense of agency can even occur when just one person holds the planchette. In a 2012 study, blindfolded participants were told a partner was moving the planchette with them when, in reality, they were the only ones pushing it around. They didn’t realize they were the ones moving it the entire time.

“The general conclusion from Anderson’s work and our own is this: The sense of agency can easily be distorted,” says Olson. “Give someone a planchette or a pendulum, give them suggestions that it will move, and they will feel as if it is moving on its own. Ultimately, though, we do not understand how sense of agency distortions occur so readily and consistently in these situations.”