Sleep paralysis and other spooky phenomena

Supernatural beliefs aren’t always incompatible with rationality. We look at the science behind common paranormal beliefs

In a vivid dream state, it can seem you are being attacked by a supernatural or alien entity. Photograph: Getty Images

In a vivid dream state, it can seem you are being attacked by a supernatural or alien entity. Photograph: Getty Images


You might not believe in ghosts, fairies or devils, but they’re hard to avoid at Halloween. Belief in such entities is often dismissed as irrational, but is there any scientific reason why a logical person might hold supernatural beliefs? Let’s look at the science behind some paranormal beliefs.

Ghost and alien attacks

At least one in five people will, at some point in their life, face the terror of being attacked by a ghost, alien, monster, witch or other strange presence at night. Victims are rendered temporarily paralysed. It is a phenomenon that has been recorded across the world, in all cultures, and is the likely origin for a whole host of supernatural stories and beliefs, including some Irish stories about abduction by fairies, and US alien abduction narratives.

Sufferers feel that they are totally awake. Science, however, has shown that this nightmare is actually caused by a peculiar but common vivid dream state called hypnagogia or hypnopompia. It is so vivid, in fact, that those who experience it can be convinced that they are being attacked by a supernatural or alien entity.

Rodney Ascher is a film director and sleep paralysis sufferer who recently released The Nightmare, which explores the first-hand experiences of people who suffer from sleep paralysis. “I interviewed people who believe that their experience happened in a state of consciousness where they’re more sensitive to the supernatural,” he says. “Most of them reported seeing variations of shadow people, including something close to the Grim Reaper, but other intruders appeared as ghosts, mechanical claws, cats and even something similar to aliens.”

These people are not necessarily irrational to conclude that their nocturnal visitors have a supernatural origin, and this may lead them, and those with whom they share their story, towards a wider set of supernatural beliefs.

Luck and control

Gamblers, athletes and fishermen might appear to have little in common. But they all have to deal with unpredictable outcomes, and they’re among the most superstitious groups of people.

Dr Caroline Watt heads up the Koestler parapsychology unit at Edinburgh University. “I have conducted research indicating that belief in the paranormal can, for some, fulfil a need for control,” she says. “The individual derives some comfort from a sense of being able to obtain information, influence people and predict the future through paranormal means.”

Richard Wiseman is professor of the public understanding of psychology at the University of Hertfordshire. He is a former magician and a sceptic who frequently debunks reports of paranormal phenomena. His research suggests that belief in good luck can make a person work harder and to persist in the face of setbacks.

“This means that they can actually create their own luck, and therefore, under certain circumstances, it is rational to believe in luck,” Watt argues.


We carve pumpkins at Halloween because of a curious scientific phenomenon. Across the world and throughout history, lights seen over swampy or marshy areas, which appear to move, have been variously associated with ghosts, spirits, witches, pixies and serpents.

In Ireland, they are associated with the soul of a man who is doomed to wander the Earth with a lantern until the end of days, and who lures travellers to their deaths on the bogs. The story was commemorated at Halloween by carving out turnips or cabbages and inserting a candle; Irish emigrants in the United States found pumpkins much easier to carve.

In their preface to the book Bog Bodies, archaeologists RC Turner and RG Scaife highlight how the discovery of human remains around bogs and marshes has always formed a part of oral history throughout Europe. Although some were Iron Age sacrifices, most appear to have died by accident or misadventure while out walking or travelling – perhaps following the lights and getting lost.

When the bodies of these missing people were eventually found, the will-o’-the-wisp – or, sometimes, fairies – often shouldered the blame. The penitential ghost may be a figure of the imagination, but the lights were not. They are linked to naturally occurring gases and tectonic strains and to bioluminescence caused by fungus and fireflies.




Paranormal encounters, by definition, defy the known laws of science. And yet, many people genuinely believe they have had this kind of experience. Most of us know such people.

Bruce Hood, a professor of experimental psychology at the University of Bristol, has conducted research that suggests people might be hardwired for magical thinking. However, exhaustive research has never presented any credible evidence of supernatural phenomena, such as telepathy or life after death.

Most scientists feel that there is no point going back over old ground, but ghost hunters and paranormal research groups, using pseudoscientific techniques, have rushed to fill the void.

“Academics who investigate the paranormal do so with rigour,” says Caroline Watt of the Koestler parapsychology unit at Edinburgh University. “The same cannot be said of amateur ‘ghost-hunting’ groups.”

While surveys on supernatural belief do appear regularly, they are generally unreliable and have little scientific value, says Lawrence Taylor, a professor of anthropology at Maynooth University and the author of Occasions of Faith: An Anthropology of Irish Catholics.

“Surveys are meaningless. If you ask someone if they believe in fairies, they will say no, but they may still be reluctant to knock down a tree in case of ‘bad luck’.”

Taylor points out that belief and disbelief are not absolute opposites; they are two ends of a spectrum. “Some may believe in ghosts but not be remotely religious. In other cases, belief may be more nuanced or qualified.”

The word “irrational” is overused, says Taylor. “Irrationality implies there is no logical reason why a person would hold a belief, but just because a belief is unscientific – that is, either impossible to prove or flying in the face of all known evidence – does not necessarily mean it is irrational.

“For the Azande tribe of central Africa, for instance, witchcraft beliefs would have made sense in the context of their world. And in Ireland, stories of returning ghosts can point to cultural values such as meeting obligations and repaying debts.”

Do Irish people still believe in the supernatural? “They don’t dismiss it,” says Taylor. “Think about it: death is the whole story. There is nothing more powerful than dealing with your own death or that of a loved one. It’s in this circumstance that potential belief becomes mobilised.”

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