Since time immemorial, we’ve seen ghosts.
Whether it’s a disembodied voice whispering in the night, the classic lady in white drifting through walls, or even a candle flickering in a room with a closed window, art and culture have made these uncanny episodes as familiar to us as they are to the mystics and psychics who claim to regularly experience them.
Maybe they’ve become so indelible for the collective psyche because they represent so much: a warning, the presence of a departed loved one, associations with horror and fear, musings about the afterlife. With a developed, self-aware mind that’s evolved to the task of pursuing and attributing meaning, it’s no wonder we’ve loaded ghosts with millennia of spiritual overtones. But maybe these ghosts haven’t entirely broken their bonds with this life, after all.
On the surface, ghosts don’t seem to have much to do with phantom limb syndrome, but recent research suggests a strong link. The clue might be in the name — where phantom limb refers to a body part that doesn’t exist, a phantom apparition might similarly be an image conjured up in our minds.
WHEN THE MIND FORGETS THE BODY
Our journey starts with a mental construct called the body schema — your constant, unconscious narrative about your body’s relationship to everything around it. Sound and vision, gravity, your nervous system’s response to the environment, the tiny channels of liquid in your ears telling you that you’re standing upright, along with countless of other physical properties whose combination gives us what feels like an unshakable sense of where we are in relation to the world and everything in it.
But changes in neurology, caused by anything from brain lesions to extreme emotional states, can make our body schema go wrong with surprising (and scary) ease. “Disruption of our networks’ patterns of activity can create sensations of being separated from your own body, perceiving the body from ‘outside,’ and shifts in perception of place and time,” says neuroscientist and neuroethicist Dr. James Giordano, professor of neurology at Georgetown University Medical Center, Washington, D.C.
Simple manifestations of such phenomena might be a feeling of déjà vu, or the lesser-known jamais vu wherein we experience something we recognize but which still seems unfamiliar.
So researchers wondered if we might bring about ghost sightings — or similar experiences — by taking experiments that have successfully treated people with body schema problems (such as those who experience pain or discomfort in a body part that doesn’t any longer exist) and going a step further.
In order to generate a whole-of-body illusion, scientists at Ecole Polytechnique Federale in Lausanne, Switzerland, put virtual reality goggles on subjects standing in an empty room. An image of themselves standing six feet ahead was projected into the goggles, and their backs were stroked with a pointed stick at the same time they perceived their virtual self being touched. When the real and virtual touching was synchronized, the subjects reported the sensation of being momentarily in the projected body. A similar experiment using a mannequin dressed in identical outfits as the subjects resulted in the sense of the self being projected onto the mannequin.
Subsequent experiments by a neuroscientist from the Karolinska Institutet, Sweden (while visiting the University College London), involved projecting an image of the participating subjects into video goggles from two cameras placed six feet behind them. Using similar touching patterns to those described above, the subjects felt they were looking at their own bodies from six feet away, their corporeal self as if disconnected from their physical body.
THE DECOUPLED MIND
But what does this tell us about seeing ghosts? As Peter Brugger, a neuroscientist at University Hospital Zurich explains: “Normal brains can easily be duped about the source of an action at a distance, that they themselves have the agency over actions.”
There’s also a direct terminological leap from phantom limb to bigger body schema concepts that could incorporate ghosts. “Phantom limb was frequently described as ‘ghost limb,’” Brugger tells Brain World. “The term ‘phantom body’ was in fact introduced to depict ghostly phenomena as phantom limb-style phenomena.”
“The difficulty is that you’re never ‘amputated’ from the whole body, but there are neurological diseases in which such an ‘amputation’ occurs at the highest level of body representation. The consequence is a split between the physical body and its representation, giving rise to many doppelganger [other self] and ghost phenomena.”
Such phenomena can arise when the localization of your body in space is projected somewhere else and no longer matches the physical location of your body. “The experience of a doppelganger has been the most thoroughly and convincingly studied in the ‘projection of body schema’ context,” says Brugger.
Researcher James Giordano adds that because we’re spiritual animals, we often interpret such phenomena through emotional lenses. “These [phenomena] can assume spiritually emotional content or be interpreted as ‘supernatural’ for some people,” he says. “It’s not unusual for people grieving to report they’ve heard or even seen a loved one who’s recently died while falling asleep or drifting out of sleep.”
We’re also not limited to a single projected body schema just because we’re limited to one physical body. Brugger reminds us that ghosts are sometimes experienced as more than just singular entities. If a haunted house contains a piercing scream, sounds of footsteps making their way along a dark hallway, or a skeletal figure draped in rags limping across the ground, these various sensations could be a multiplication of the body schema — just like multiple voices tormenting a schizophrenic all belong to a single sufferer.
RELATED PHENOMENA
The list of supposedly paranormal activities, whose mysteries can be easily explained as one’s skewed sense of their own body awareness, is rather long. Many people claim to have experienced psychography (usually called automatic writing), where they claim a disembodied entity or intelligence from beyond the physical world takes control of their hand to write messages to the living. Maybe it’s indeed the subject doing the writing, but projecting the body schema of their hand, arm, and the content of what they’re writing elsewhere.
Brugger interviewed accomplished mountaineers, many of whom had climbed to altitudes of over 27,000 feet, who had reported sensing unusual presences, and sometimes full out body experiences. The common thread was that they’d all made their climbs to such heights without supplementary oxygen, and hypoxia (a shortage of oxygen) is just the kind of radical shift in brain physiology that can turn the body schema on its head.
A third party speaking from beyond the body is a widely documented aspect of schizophrenia, and it might simply be the audio version of the phantom limb sensation, along with other body schema projections. When it comes to the mind’s motor control, simply thinking a thought is enough to make the sufferer feel as if they are “hearing” it voiced by a separate entity.
That’s further evidenced by the fact that if you can observe a schizophrenic while he or she is hearing voices, their larynx moves as they subvocalize the thought they’re attributing elsewhere. Today, scientists also know that brain areas associated with motor speech production are activated when a schizophrenic hears voices. It’s not the only giveaway that the body reveals. As long as you’re in your right mind, it’s impossible to tickle yourself, but, as you might expect, people with body schemas projected elsewhere experience the sensation as if a real other person is doing the tickling.
It’s also fairly common for people to report having floated in the air looking down onto themselves after a sudden and severe injury, during sleep paralysis, after particularly demanding sports, or during intensive meditation — all phenomena that can cause spikes in levels of oxygen, blood sugar, or neurochemicals.
WHY WE SEE GHOSTS
The reasons why certain brain states have us experience seeing spirits are as diverse as the variety of brain states themselves, everything from trauma to fatigue. Giordano explains how some cases of temporal lobe epilepsy result in symptoms that are construed or perceived to be spiritual or religious. “They can include bodily sensations like smells, feelings of lightness or the presence of another being and heightened emotions,” he says, “sometimes to the point of rapture.”
As we’ve already seen, schizophrenia and other psychotic disorders can induce perceptions of the paranormal — although, curiously, auditory and tactile hallucinations are more common under most conditions. Visual hallucinations are more associated with drug-induced states, as many recreational and medical users can attest.
There’s also a common religious or spiritual dimension felt by sufferers of delusional disorder, a psychiatric condition associated with either bizarre or nonbizarre delusions of thinking. According to a 2010 study, religious delusions are generally less troublesome to the sufferer than other types, like hypochondria or paranoia, and can be associated with delusions of grandeur. Might that help explain why we think a deceased relative goes to the extraordinary steps of making contact from beyond the grave to impart some serious message?
As Giordano explains, there’s a common neurological thread to such disorders. “It appears to involve loss of network integration between the brain pathways that parse imagined thoughts and stream of consciousness from the experience of events out in the external environment.”
But as we’ve already seen, far more common occurrences — like profound fatigue or dehydration, and even being in a hypnagogic or hypnopompic state (the scary-sounding scientific terms for falling asleep or waking up) — can prime the brain to hallucinate ghosts and goblins.
There are even cases where extremes of emotion can result in ghostly visitations. “It’s somewhat rare,” Giordano begins, “but sudden and intense emotion can alter patterns of activity in neural networks that integrate sensory and emotional processes. That can then cause disconnection, derealization or other altered sensory perception. It might produce a feeling of being ‘detached’ or ‘removed’ from your body, hearing voices or experiencing the presence of another person.”
In fact, emotions might help explain another commonality to ghost sightings. Along with the fact that they’re often visually unclear, many witnesses report particular feelings associated with these incidents.
In cases involving parietal lobe lesions, Brugger wonders if their presence might help explain the appearances of ghosts being reported as pale, transparent, milky, colorless, etc. “Ghosts are often at the verge of vision,” he says. “The parietal lobe is responsible for the spatial extension of a body, localization of your ‘felt’ presence in space.”
“In the convergence zones between the parietal and occipital lobes, things are visualized incompletely and appear misty. The color gray is very frequently mentioned. If the irritation was wholly in the occipital lobe, things would be more naturally colored like a typical visual hallucination.”
Eliciting extreme emotion in test subjects — ethics notwithstanding — is probably the easiest way to replicate such conditions for experimentation, but, as Brugger adds, explaining ghosts is just one item on a very long list of things we might give account of once we understand how to untangle emotional responses from neural circuitry.
“There are a lot of effects emotions have on cognitive processing that we don’t understand,” he says. “A tentative answer might be that emotions are mediated by — among other regions — the limbic system, which is widely linked throughout the brain, especially to centers that mediate bodily experience.”
For now, we might have to rely on methods that — however advanced — are still crude because of our limited understanding about how the brain works. Back in 1999, Giovanni Berlucchi, of the University of Verona, and Salvatore Aglioti, of the University of Rome, published research demonstrating how electrical stimulation of the insula caused illusions of changes in one’s body position as well as induced feelings of being outside the body.
Neuroscience has advanced considerably in the subsequent 16 years, but as long as we hide under the covers at night because we hear or see inexplicable things roaming around, instead of switching on some brainwave scanner to reset and reorient our body schema, we have a long way to go.
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