A ghost horse, obviously. (Photo: geezaweezer/Flickr)

Despite an exterior presence that exudes a certain amount of common sense and belief in the scientific process, more than just about anything, I desperately want to see a ghost. I'm Scully in the streets, but Mulder in the sheets.

I've dropped some serious coinage on tours of haunted places. I've examined “ghost photos” with a wide variety of photo-enhancement technology. I've snuck into decrepit, abandoned buildings, where spirits of the dead supposedly linger. I've taken out the Ouija board, and chanted “Bloody Mary” into a mirror on a candlelit Halloween. And still: Nada. Not one damn moment of ghostly contact.

Enough people have claimed to have seen or “felt” ghosts that there has to be something to it. Am I just an unlucky individual who the ghosts aren't interested in chatting with? Am I that boring? Or am I not tuning into their signal at the right frequency? Turns out, the reality may be closer to that last theory than anything else.

Let's start with an assumption based on lack of evidence to the contrary: Ghosts do not exist. There's no evidence the blurry visages people claim to see are actually manifestations of people who have died. If there were legitimate proof, scientists would pounce on the chance to prove life after death was real. But that lack of evidence still doesn't account for the fact that enough people claim to see ghosts—with the vast majority of them not attempting to monetize this claim—that all can't possibly be fraudulent assertions.

People do see things. But why?

In 1902, the “Father of American psychology” William James published The Varieties of Religious Experience: A Study of Human Nature, where he linked singular “religious experiences” to psychological disorders in the brain. To him, they were the result of “delusional insanity.” This laid the general groundwork that scientists should focus on the brain in order to locate a cause for spiritual occurrences. And so began the long dance with schizophrenia as a possible cause.

I've dropped some serious coinage on tours of haunted places. I've examined “ghost photos” with a wide variety of photo-enhancement technology.

The links are obvious. Schizophrenia affects nearly one percent of the global population, as many as 51 million people, which makes it large enough to account for the breadth of ghostly claims. And while the symptoms that lead to diagnosis are varying, there are a few checkpoints that align perfectly with the feeling of ghostly presences, particularly audio/visual hallucinations and delusional thinking. In 1994, the University of Adelaide in South Australia confirmed that there was a correlation between instances of schizophrenia and belief in the paranormal. The correlation, however, was only significant for male subjects.

But, still, a correlation between feeling ghosts and schizophrenia is too broad of a correlation to really accomplish anything. What's actually going on in the brain to account—at least partially—for claims of ghost sightings?

In 2014, researchers in Switzerland brought 12 people who reported having “secondary representations of their body” into the laboratory. In the scientific world, this sensation is known as Feel of Presence (FoP), a murky sense that other people are in the room with you, similar to the experience of those claiming to have encounters with the spirit world. But there's something unique about FoP that points toward a more specific cause.

“Feeling of Presence has specific characteristics,” says Giulio Rognini, one of the study's co-authors. “If the patient was standing, the presence was felt standing. If the patient was lying down, the patient felt as if the presence was lying down.”

In other words, there's a shared movement between the person claiming to feel the invisible presence and the presence itself. This implies a sort of doubling in the patient's brain, which further implies signals somehow getting crossed. Rather than attributing their own movements and activities to their own bodies, subjects attribute them to ghostly presences that are near them. With FoP as a focal point, scientists devised an experiment to re-create this feeling and more closely examine what's happening in the brain during those moments of FoP.

Researchers blindfolded their test subjects and placed them between two robots. Participants were then instructed to reach forward and make a motion on the robot sensor in front of them. When they did, the robot behind them mimicked the same motion on the participant's back at the exact same time, in a loop of sorts. This was a little strange—imagine how it feels to rub your hand, but then feel the rubbing on your knee—but it only got spooky once they slightly delayed the reaction between the robots. “That replicated the effect of a lesion in those areas of the brain that integrate your own body signals,” Rognini says.

When the researchers tweaked the timing, respondents claimed it felt as if some other presence was touching them. Others claimed it felt as though the room was now full of people, rather than the few researchers who were actually present. (Again, respondents were blindfolded during the act.) A few were so freaked out by the “ghostly presence” that they asked to end the test.

When they crunched the data to see what parts of the patients' brains were firing during these lab-created FoP episodes, researchers saw activity in three areas of the central cortex that deal with visual input, memories, and perception. “These areas give you representation of your body,” Rognini says. “They give you the [feeling] that you are a specific body.” When that sensory process is fudged, your brain makes the assumption that there's someone else in the room with you.

Now, this kind of knowledge can potentially go a long way toward finding a cure for alleviating certain symptoms of schizophrenia. Knowing where the brain is malfunctioning is the first step toward fixing it. But as far as whether or not this information can actually “cure” claims about seeing/feeling ghosts, well, that's about as likely as ghosts being a white blob with two black holes for eyes.

There's also the—for lack of a better term—linguistic issue with “ghosts.”

If you see a tree, you don't know it's a “tree” until someone teaches you to associate that four-letter word with the leafy wooden thing sticking out of the ground. In the same way, if someone feels an invisible presence around them, they don't automatically associate it with “the spirit of a dead person” until they're taught to do so. The “cure” for claims of seeing ghosts, then, is a two-pronged affair.

As this 1997 examination into a trio of spiritually based case studies attests, the other half of the problem involves cultural associations. “It would be quite wrong, then, to 'treat' spiritual psychotic experiences with neuroleptic drugs, just as it is quite wrong to 'treat' political dissidents as though they were ill,” the authors write. In other words, even if the most perfectly designed drug fixes whatever's going on in the person's brain, it's not enough to counter some great ghost stories.

Thanks a lot, whoever is responsible for that initial association between “other, unseen beings” and “remnants of the dead.” (The earliest recording of a ghost story was taken down by 1st-century Roman reporter extraordinaire, Pliny the Elder.) Because of that link, ghosts are never going to die.