Scientists Tried to Find a Logical Cause of Ghostly Presences. They Found Something Even Scarier.

Here’s what you’ll learn when you read this story:

• While many people have experienced encounters with what they think might be a ghost, studies trying to make sense of this scientifically have never found an explanation.
• Researchers compared accounts from three very different groups, looking for overlap.
• Spiritualists, extreme athletes, and psychiatric patients described strikingly similar ghosts, but no definitive cause emerged.

Ghosts haunt our subconscious every Halloween. The living often wonder whether a hazy apparition, a sudden chill out of nowhere, or the echo of a disembodied voice might be coming from the spirit realm. Paranormal investigation shows aside, there has been no scientific way to prove this so far. They could be vestiges of the dead—or maybe they only exist in our imaginations.

Perceiving ghosts is a phenomenon known as felt presence. Psychologists, neurologists, and neuropsychologists have tried to explain why people sense someone who isn’t there. Results are usually inconclusive. Sometimes, felt presence could be a side effect of bereavement or a hypnagogic illusion, which is experienced on the edge of falling asleep. It could also be a symptom of sensorimotor disruption in psychosis. Searching for a neuropsychological explanation for so many ghost reports, researchers gathered data from wildly different groups. Some subjects were highly spiritual. Others had conditions involving paranoia and hallucinations. A few were endurance athletes who swore something was out there with them.

“Research comparing these phenomena remains rare,” the researchers said in a study published in Psychological Medicine. “A comparative approach to the phenomenology of felt presence has the potential to identify shared and unique processes underlying the experience across these contexts, with implications for clinical understanding and intervention.”

To find out whether anything about ghostly presences was a shared experience, the research team recruited three groups of people. Subjects in the first group either identified as “voice-hearers” or had been diagnosed with a psychiatric or neurological condition such as schizophrenia. Many subjects from the second group were found through spiritual organizations. Hardly any had clinical diagnoses, but some described episodes of clairvoyance (visions), clairsentience (sensations or feelings), or clairaudience (hearing disembodied voices). In the final group were athletes who participated in endurance or extreme sports, sometimes alone. Only a few had any psychiatric diagnoses. The groups were given online questionnaires asking them to describe sensing a ghost.

When it came to the perception of something incorporeal, these presences tended to be described as more likely to be human than anything else. About half of the subjects described the presence as human rather than anything else. About half sensed it through touch, and nearly as many through hearing. Wherever the presence lurked, it usually hovered just behind the person or somewhere nearby. Subjects who felt a presence frequently tended to cast it as angelic or demonic. Intensity varied widely, from “it feels like someone is standing behind me and watching me” to “a feeling of utter terror, as if this presence had the power to hurt me.” These spirits and entities carried their own identities and backstories. Those ghosts were usually deceased loved ones. But some were unexplainable.

An ethereal young woman haunted one subject, who sensed that their lives had somehow become intertwined and absorbed emotions, words, and images from her. The apparition appeared as an overlay on the room, bringing her own spectral surroundings along with her. Another subject, an endurance athlete, recalled nearly succumbing to hypothermia mid-race when an unexplained bright light appeared ahead. The athlete pressed on and finished, convinced that without that light, the race would have ended in death. Another subject in the study could barely describe the sensation—a presence that seemed as though it should be visible or audible but dissolved the instant they looked or listened, inferable only as a sudden realization or a sense of creeping dread. But whenever the subject searched for it or tried to hear it directly, there was nothing.

Felt presence turned up most often in people already prone to hallucinations, and paranoia frequently came with it. The ghosts themselves differed in some respects but overlapped in many more. Voice-hearers reported the richest sensory detail of all, including touch and bodily changes. Spiritualists were especially likely to feel presences when they were in a meditative state of trying to connect with the spirit world. This is similar to absorption, when someone becomes deeply immersed in mental imagery that may or may not have a basis in reality. Hypnagogic encounters while falling asleep or waking up occurred in all three groups. But despite the headway their research made, scientists still can’t name what causes these presences. It seems that whatever ghosts are, they have once again eluded us.

“Given that some felt presences lack clear embodied characteristics,” the researchers said, “the possible existence of other kinds of illusory presence demands further investigation.”