What science has to say about things that go bump in the night
As Halloween draws ever nearer, vampires, witches and ghosts are hard to escape on our TV screens, shop windows and streets.
For most of the population, scaring ourselves with fantasies of witches, vampires or werewolves at Halloween is all in good jest – belief in these kind of monsters died out centuries ago.
Yet when it comes to ghosts, things are a little different. Most of us know at least one or two totally rational, level-headed adults who claim to have seen or experienced a ghostly presence.
One survey in 2017 found, in fact, that around a third of Brits believe in ghosts, with even the most sceptical of us often spooked by unexplained bumps in the night.
So what is it about ghosts that’s captured our imagination for so many centuries? And is there a rational explanation for why sightings are so common? For sceptics – or scaredy-cats looking for some comfort – here are five of science’s best guesses.
Verbal suggestion and the power of belief
Simple yet effective, several studies have shown that people are more likely to report a location as being haunted if it’s been suggested to them that it is. This kind of suggestion is also the way that a lot of “psychics” operate.
In one study, for instance, two groups of participants were shown around a theatre. One group was told the theatre was haunted, while the others weren’t. In a survey taken afterwards, the group who had been told the theatre was haunted reported more intense experiences – relating to paranormal activity – than the other group.
It’s also been suggested that the power of our will is much stronger than we might think – and simply wanting to see a ghost might be powerful enough to create an impression of one.
Michael Persinger, a Canadian neuroscientist, has studied the effect of electromagnetic fields on people’s perception of “ghosts”.
He hypothesises that pulsed magnetic fields – which we can’t detect on a conscious level – can cause unusual activity patterns in the brain’s temporal lobes and lead to people perceiving a “presence” in a room.
Though there has been some pushback against his theory, other scientists have found that places with a reputation for being haunted – like Hampton Court – do have unusual magnetic fields.
Another common feature of supposedly “haunted” locations is mould growth, with some anecdotal research reporting mould in several famously “haunted” locations. Homeowners with mould growing inside their houses have also reported hallucinations and visions which may be linked to toxins that the mould produces.
Preliminary research indicates that mould can cause symptoms like irrational fear and dementia-like symptoms.
Carbon Monoxide poisoning
Another theory that puts ghost sightings down to external factors, Carbon Monoxide has been blamed in some cases for “ghost” sightings.
In 1921, Dr W.H. Wilmer told a story in a journal about a family who insisted they were being haunted after moving into an old house.
Upon further investigation, it turned out a faulty pipe was leaking carbon monoxide into their home and causing the hallucinations responsible for the “ghosts.” Similar cases have been reported in recent years.
Another situation in which many claim to experience the presence of spirits is while using a Ouija board – designed to let users “communicate” with spirits.
Ouija boards are decorated with a series of letters as well as a “yes” or “no” in the corners of the board and a “goodbye” on the bottom. Participants put their hand over a pointer called a “planchette” and it is the spirit who supposedly moves their hand(s) towards certain letters or words when the user asks a question.
The curious thing about Ouija boards is that participants’ hands do seemingly move of their own accord – but scientists have put this down to an effect called the “ideomotor effect” rather than ghosts.
The ideomotor effect is an example of involuntary, unconscious physical movement, and is a way for our bodies to speak to themselves without us being aware.
When using a Ouija board, users will often unconsciously have messages that they want to receive when asking questions to a “spirit.” This means our body responds to our brain’s unconscious desires and moves our hand without conscious input – giving the impression that it’s being controlled by external forces.