If you’ve ever had the eerie feeling that someone was in the room when you were sure you were alone, you may be afraid to admit it.
Perhaps it was a profound experience that you would like to share with others. Or – more likely – it was something in between.
Unless you had an explanation to help you process the experience, most people will have difficulty understanding what happened to them. But now research shows that this ethereal experience is something we can understand, using scientific models of the mind, body and the relationship between the two.
One of the largest studies on this subject was conducted way back in 1894. The Society for Psychical Research (SPR) published their Census of Hallucinations, a survey of more than 17,000 people in Britain, the US and Europe.
The study aimed to understand how common it was for people to make seemingly impossible visits that foretold death. The SPR concluded that such experiences occur too often to be a coincidence (one in 43 people surveyed).
In 1886 the SPR (whose patrons included former British Prime Minister William Gladstone and the poet Alfred, Lord Tennyson) published Phantasms of the Living.
This collection included 701 cases of telepathy, premonitions and other unusual phenomena. For example, Reverend PH Newnham, from Devonport in Plymouth, told the story of a visit to New Zealand where a nighttime presence warned him not to go on a boat trip at dawn the next morning. He later learned that everyone on the journey had drowned.
Phantasms were criticized at the time for being unscientific. The count was received with less skepticism, but still suffered from response bias (who would bother to respond to such a survey except those who have something to say).
But such experiences live on in homes around the world, and contemporary science offers ideas for understanding them.
Not such sweet dreams
Many of the stories SPR has collected sound like hypnagogia: hallucinatory experiences that occur on the borders of sleep.
It has been suggested that several religious experiences from the 19th century have a basis in hypnagogia. Presence has a particularly strong link with sleep paralysis, which affects about 7% of adults at least once in their lives.
In sleep paralysis, our muscles remain frozen like a hangover from REM sleep, but our minds are active and awake. Studies have suggested that more than 50% of people with sleep paralysis report a presence.
Although the Victorian presence documented by the SPR was often benign or comforting, modern examples of presence caused by sleep paralysis tend to radiate malevolence.
Societies around the world have their own stories of nocturnal presence – from the Portuguese ‘little monk with the pierced hand’ (Fradinho da Mao Furada) who could infiltrate people’s dreams, to the Ogun Oru of the Yoruba people of Nigeria, believed to be a product of the spell cast on victims.
But why would an experience like paralysis create a sense of presence? Some researchers have focused on the specifics of waking up in such an unusual situation. Most people find sleep paralysis scary, even without hallucinations.
In 2007, sleep researchers J. Allen Cheyne and Todd Girard argued that when we wake up paralyzed and vulnerable, our instincts make us feel threatened and our minds fill the gap. If we are prey, there must be a predator.
Another approach is to look at the similarities between visitations in sleep paralysis and other forms of felt presence. Research over the past 25 years has shown that presence is not only a permanent part of the hypnagogic landscape, but also occurs in Parkinson’s disease, psychosis, near-death experiences and grief. This suggests that it is unlikely to be a sleep-specific phenomenon.
Connection between body and mind
We know from neurological case studies and brain stimulation experiments that presence can be elicited by physical cues.
For example, in 2006, neurologist Shahar Arzy and colleagues were able to create a “shadow figure” experienced by a woman whose brain was electrically stimulated in the left temporoparietal junction (TPJ).
The figure seemed to reflect the woman’s body position – and the TPJ combines information about our senses and our body.
A series of experiments from 2014 also found that disrupting people’s sensory expectations appears to induce a sense of presence in some healthy people. The way the procedure the researchers used works is to make you feel as if you were touching your own back, by synchronizing your movements with a robot directly behind you.
Our brain understands the synchronization by inferring that we are producing that sensation. When that synchronization is subsequently disrupted – because the robot gets a little out of sync – people can suddenly get the feeling that another person is present: a ghost in the machine. Changing the sensory expectations of the situation produces something called a hallucination.
That logic could also apply to a situation like sleep paralysis. All our usual information about our body and our senses is disrupted in that context, so it is perhaps no surprise that we feel like something is ‘different’ with us. We may feel like it’s another presence, but it’s actually us.
In my own research in 2022, I tried to trace the similarities in presence from clinical records, spiritual practice, and endurance sports (which are known to produce a range of hallucinatory phenomena, including presence).
In all these situations, many aspects of the sense of presence were very similar: for example, the subject felt that the presence was directly behind him. Sleep-related presence was described by all three groups, but so were presence caused by emotional factors, such as sadness and grief.
Despite its ancient origins, the science of felt presence has only just begun. Ultimately, scientific research can give us one overarching explanation, or we may need multiple theories to explain all these examples of presence.
But the encounters people describe in Phantasms of the Living are not phantoms from a bygone era. If you haven’t had this disturbing experience, you probably know someone who has.
Ben Alderson-Day, Associate Professor of Psychology, Durham University
This article is republished from The conversation under a Creative Commons license. Read the original article.
