As the name suggests, anomalistic research is research into anomalies – weird and wonderful phenomena that appear not to be explicable in conventional terms. Such phenomena have an inherent fascination for most people and I’m no different. Up until early adulthood, I personally believed in a whole range of paranormal phenomena. Then I read a book called Parapsychology: Science or magic? by psychologist James Alcock. That book convinced me that there were convincing non-paranormal explanations for such phenomena. I became a sceptic. For a long time after that, my interest in scepticism was little more than a hobby – a private passion that was not part of my academic career. But gradually I began to write the odd paper on this stuff and carry out small-scale projects in this area. Eventually, I realised that this was the stuff that really fascinated me and it became the sole focus of my research and teaching.

Parapsychologists would typically limit their subject matter to three core concepts. The first is extrasensory perception or ESP. There are three types of ESP. The first is telepathy, the idea that people can sometimes transmit information between minds directly without the use of the known sensory channels. The second is precognition, the claim that sometimes people obtain knowledge of future events in ways that cannot be explained in conventional terms. Finally, there is clairvoyance, the notion that people can sometimes obtain information about remote objects and events without the use of the known sensory channels. The second core concept of parapsychology is psychokinesis or PK, the alleged ability to influence the external mind by the power of thought alone. The third area of interest to parapsychologists is evidence relating to the possibility of life-after-death – and that would include, of course, evidence relating to ghosts.

Anomalistic psychologists are interested in all of those areas that interest parapsychologists but many more besides. Indeed, anomalistic psychologists are interested in pretty much anything weird. So, in contrast to parapsychologists, anomalistic psychologists are also interested in such phenomena as astrology, alien abduction claims, the Loch Ness Monster, superstitions, complementary and alternative medicine, and dowsing, to name but a few. Anomalistic psychologists typically assume, as a working hypothesis, that paranormal forces do not exist and try to develop and put to the test alternative non-paranormal hypotheses to explain ostensibly paranormal events. However, they sometimes do directly test paranormal claims and, similarly, parapsychologists will sometimes test non-paranormal explanations. In this respect, the difference between the two disciplines is relative not absolute.

Few parapsychologists or anomalistic psychologists would describe themselves as “ghost-hunters”, even the relatively few that carry out fieldwork at reputedly haunted locations. Those who do adopt such a label tend, by and large, to be amateur hobbyists with little formal scientific training or proper understanding of scientific methodology. Typically ghost-hunting groups like to use lots of technology in their investigations and to claim that they are carrying out objective scientific investigations. In fact, they are searching for any evidence – no matter how weak – that ghosts really do exist.

Different people will give different answers to the question, “What is a ghost?” This is nicely illustrated by the three main explanations for so-called poltergeist activity which allegedly involves many different kinds of disruption including objects flying around the room, loud noises, fires spontaneously starting, electrical malfunctions, and so on. The traditional explanation – and the one favoured by ghost hunters – is that poltergeists, like other ghosts, are the spirits of people who have died who are for some reason hanging around on this earthly plane. The word poltergeist literally translates as “noisy ghost”. The second main explanation, one favoured by many parapsychologists, is that poltergeist activity is a genuinely paranormal phenomenon but that it has nothing to do with spirits. Such parapsychologists point out that the disruptive activity typically only occurs in the presence of a single individual, often referred to as the “focus” of the activity. That individual is someone who is psychologically deeply troubled. The idea is that their inner psychological turmoil is somehow externalised in the form of disruptive psychokinetic activity. Thus parapsychologists will sometimes refer to poltergeist activity as recurrent spontaneous psychokinesis (or RSPK). Finally, sceptics often tend to agree with such parapsychologists regarding the source of such disruption but disagree about the means. They would explain many cases as simply being hoaxes carried out by attention-seeking individuals. Not all reports of ghosts involve such disruption of course. Sometimes apparitions are said to bring messages from beyond the grave or may be simply repeatedly replay some scene from their past lives without any apparent awareness that they are being observed.

As a child, I was terrified of ghosts and hated having to sleep alone in the dark. As an adult psychologist who no longer believes in ghosts, I am simply fascinated by all ostensibly paranormal phenomena. The fact is that belief in ghosts is found in all known societies, both historically and geographically. A fairly substantial minority of the population claim that they have personally experienced a ghost. For me, this can only mean one of two things. If ghosts really do exist, this has profound implications for our scientific understanding of our place in the universe and for the nature of consciousness. On the other hand, if, as I suspect, ghosts do not really exist, this can potentially tell us a lot about human psychology.

Opinion polls repeatedly show that a large proportion of the population believe in ghosts. For example, in 2006 Readers’ Digest magazine published the results of a survey of over a thousand British adults. One of the questions was, “Do you think that ghosts or the spirits of dead people can communicate with us or can come back in certain places or situations?” Over half of the respondents said “yes”, with just over a quarter saying “no” and the remaining fifth saying they didn’t know. Belief was higher in women (64%) than men (43%) and was markedly lower in the over-65s compared to other age groups.

Another question was, “Have you ever seen a ghost?” Again, more women (21%) than men (16%) answered positively and, once again, the lowest endorsement rate (11%) was found in the over-65s.

There are widely shared expectations in our society that certain types of location, such as castles and old pubs, are more likely to be haunted than others. In some cases, there are clear vested interests in maintaining the spooky reputation of such properties. However, it is also the case that some places just feel inherently spookier than others. Some of the factors that cause this feeling are pretty obvious, such as dim illumination and high ceilings. In terms of our evolutionary history, it would make sense for such locations to make us feel on edge in case predators were lurking, ready to pounce. Other environmental factors have also been suggested as possibly causing anomalous experiences in susceptible individuals, including complex electromagnetic fields (either naturally occurring or manmade) and the presence of infrasound (i.e., sound energy below the audible frequency range). The evidence supporting these suggestions is, however, mixed at best.

Interestingly, belief in ghosts is higher in the North West of England than elsewhere in the UK – and almost one in four people in the North West claim to have actually seen a ghost. Being from the North West myself, I am aware of the fact that Liverpudlians do love telling tall tales – and whether you believe in ghosts or not, everyone enjoys a good ghost story!

We all have a fairly standard idea of what a ghostly encounter is like largely based upon the movies. Ghosts appear as full-sized transparent apparitions that can walk through walls, right? Well, not necessarily. In fact people reporting ghostly encounters are much more likely to report a range of slightly less dramatic manifestations including unexplained noises or smells (such as tobacco smoke or p0erfume), changes in temperature, electrical malfunctions, or even just a strong sense of presence – the feeling that someone is there, even if you can’t see them or hear them.

Although all cultures have some notion of ghosts, the details vary considerably across time and space in terms of the appearance of ghosts and their behaviour. For me, this is very strong evidence that ghosts do not reflect some eternal unchanging afterlife but instead are themselves the product of cultural expectations.

Two types of technology appear to be most strongly associated with ghosts. The first is photography. From its inception, the history of photography has been intimately intertwined with the history of psychical research. Photography itself was a somewhat mysterious process to most people when it first appeared and what to modern eyes look like rather obvious double-exposures looked like genuine photographs of spirits to many people. Indeed, many photographers specialised in such fraudulent activities. Most ghost photographs are, however, not the result of deliberate fraud. Some are the result of something or someone being caught in the shot that the photographer was not aware of at the time. Others are just tricks of the light or familiar objects viewed from unfamiliar angles giving the appearance of faces or figures. Might some really be ghosts caught on camera? It is hard to say – but what we can be sure of is that it has never been easier to produce convincing hoax photographs and videos thanks to readily available software. One relatively recent idea is that apparent spheres of light, referred to as “orbs”, appearing in photographs taken with digital cameras are, in fact, spirit energy. This idea is dismissed by camera manufacturers who insist that the “orbs” are in fact out-of-focus specks of dust caught in the flash from the camera.

The second type of technology that has often been associated with ghosts is communications technology. It is said that no less a figure than Thomas Edison himself is believed to have considered the possibility of a device to communicate with the dead. Although not the most common means for ghosts to make contact, there have always been anecdotal reports of messages from the dead arriving through telephones, radios and televisions. Some ghost-hunters, however, believe that it is possible to record spirit voices by leaving a recording device in record mode in supposedly haunted locations – or even just recording from a radio not tuned to a specific radio station. The recordings are referred to as Electronic Voice Phenomena or EVPs. There are many websites where you listen to examples of EVPs for yourself. The audio clips are usually very short and of very poor quality. Whereas believers in the paranormal claim to hear clear messages from beyond, sceptics point out that you typically cannot make out what the message is supposed to be until someone tells you. In other words, the interpretation of the ambiguous stimulus is strongly influenced by subjective factors. In some cases, of course, it is quite possible that the ghost-hunters have inadvertently recorded the voices of living people.

Most claims of ghostly encounters rely entirely on subjective evidence which will never be enough to convince sceptics. The Holy Grail of psychical research is therefore to obtain objective evidence that ghosts really do exist. Communications technology is extremely popular in this regard as it often assumed that the ghosts have messages that they wish to transmit to the living – and a quick phone call would obviously achieve that more effectively than making your lights flicker on and off!

I have spent far more nights in reputedly haunted locations, usually for some TV company, than I care to recall. I have never experienced anything out of the ordinary although I have often witnessed people with over-active imaginations scaring themselves witless in such settings. I prefer to carry out psychological experiments under controlled conditions. For example, we carried out a study to investigate the claim that manipulating complex electromagnetic fields and/or infrasound (sound energy below the audible frequency range) could produce anomalous experiences in susceptible individuals. Our results did not support such claims but did show that the simple power of suggestion was sufficient to cause such experiences. We have shown similar effects of suggestion in other studies underlining the need to be very cautious in accepting eyewitness reports of ghosts as being accurate. We have also shown that believers in the paranormal appear to be more susceptible to false memories than sceptics.

If I had to summarise the main psychological factors underlying belief in and experience of ghosts, I would highlight the following. First, context: you are much more likely to have an anomalous experience in a place if someone tells you the place is haunted than if they don’t. Second, belief: believers are much more likely to report anomalous experiences and to believe they were caused by ghostly intervention than sceptics. Third, unusual experiences: for example, episodes of sleep paralysis are often interpreted as ghostly visitations when in fact they are hallucinatory. Fourth, general cultural acceptance: ghost stories are very common in all types of the media. Finally, our fear of our own mortality: belief in ghosts is simply the downside of belief in life-after-death.

Often when ghost believers present their claims, they insist (a) that they themselves were sceptics until they had their ghostly encounter and (b) they ruled out all non-paranormal explanations before finally having to conclude that it really was a ghost they had encountered. Rarely is this the case.

It simply is not possible to prove that ghosts don’t exist. No matter how many cases are debunked, it is always possible to argue that other cases are genuine. However, if alternative explanations can be supported by good empirical evidence, the case in favour of ghosts being real gradually becomes weaker and weaker.

I once took part in a TV series called Haunted Homes. The star of the show was our psychic, Mia Dolan, who claimed to be able to contact the spirits. Our paranormal investigator was Mark Webb, who would bring huge amounts of technical kit to each investigation. My role was to be the professional wet-blanket – the sceptic. In contrast to other well-known ghost-hunting programs, no one taking part in ours was prepared to fake stuff. As a consequence, very little happened and we did not get a third series. The only things that did happen always happened just in people’s heads – nothing was ever recorded on video or audio. With one exception.

Most of the programs featured ordinary houses that their owners believed were haunted but one featured Radio Beacon, a radio station in the Midlands. Amongst other phenomena that had been reported there were the voices of children singing “Ring o’ Roses” and the sound of a ghostly sneeze. Two of the employees at the radio station were asked to keep a video diary before we arrived and they thought they heard the sneeze whilst sitting on the landing in the dark. Better still, the sound was recorded during the overnight vigil when we did arrive. I was confronted on camera with this evidence and I made the point that, while the noise might indeed be a sneeze, it could be 101 other things. The next night, just before we started recording, I popped into the loo on the landing where the sneeze had been recorded. As I emerged from the cubicle, there was Mark, our paranormal investigator, with a very disgruntled look on his face, pointing to the wall. I looked to where he was pointing and there on the wall was… an automatic air-freshener! We waited until it went off and, sure enough, that was the sound that had been recorded – not a ghostly sneeze at all. The final program made a great deal of the recording of the ghostly sneeze – but sadly did not have room to include the explanation!