There is an old joke about a university lecturer who asks his class, “Has anyone here ever seen a ghost?” Fifteen students put their hands in the air. Next, the lecturer says, “Well, who here has touched a ghost?” This time only five hands go up. Curious, the lecturer adds, “OK, has anyone actually kissed a ghost?” A young man sitting in the middle of the lecture theater slowly raises his hand, looks around nervously, and then asks, “I’m sorry, did you say ‘ghost’ or ‘goat?’”

Thankfully, the results from national surveys have yielded more clear-cut findings. Opinion polls have consistently shown that around 30 percent of people believe in ghosts, and about 15 percent claim to have actually had a ghostly experience (Musella 2005). James Houran has carried out a great deal of research into the nature of these ghostly experiences. Houran is an interesting fellow. During the day this mild-mannered statistician works for a well-known Internet dating site creating mathematical models that help promote compatibility. By night Houran transforms into a real-life ghost buster, conducting surveys and studies that aim to solve the mystery of hauntings. Fifteen years ago, he analyzed almost a thousand ghostly experiences to discover what people report when they believe that they have encountered a spirit (Lange et al. 1996).

Houran’s work revealed that reports of full-fledged apparitions are very rare. In fact, they account for only 1 percent or so of sightings; when such figures do turn up, they usually appear at the foot of a bed as people are either waking up or drifting off to sleep. Around a third of Houran’s reports involve rather fleeting visual phenomena, such as quick flashes of light, odd wisps of smoke, or dark shadows that move furtively around the room. Another third involve strange sounds, such as footsteps from an empty room or ghostly whispering. The remaining third are a mixture of miscellaneous sensations, including odd odors of flowers or cigar smoke, sensing a ghostly presence, or feeling a cold shiver down one’s spine.

For well over a century, scientists have attempted to explain these strange experiences. Like much of the research into alleged paranormal phenomena, their work tells us a great deal about our brains, beliefs, and behavior.

The Rose without a Thorn

London’s Hampton Court Palace has been home to some of Britain’s most famous kings and queens. Nowadays the palace is a popular historical attraction, playing host to more than half a million visitors each year.

The palace is famous for many things: It houses invaluable works of art from the Royal Collection, contains the best-preserved medieval hall in Britain, and boasts a giant Tudor kitchen. It is also considered one of the most haunted buildings in Britain. Various spirits allegedly haunt the palace. There is a “lady in gray” whose walks through the cobbled courtyards are as regular as clockwork, a “woman in blue” who continuously searches for her lost child, and a phantom dog that lives in Wolsey’s closet. However, despite stiff competition, Hampton Court’s most famous spirit is that of Catherine Howard.

Henry VIII ruled Britain during the first half of the sixteenth century, but he did not have a great track record when it came to relationships. He cheated on his first wife, beheaded his second, lost his third while she was giving birth to his only son, and divorced his fourth. In a move that would make even the most experienced marriage counselor raise an eyebrow, the forty-nine-year-old Henry then became infatuated with a nineteen-year-old courtier named Catherine Howard. After a brief period of wooing, Henry married Howard, publicly declaring that she was his “rose without a thorn.”

A few months after getting married, Catherine found herself very much in love. Unfortunately, the apple of her eye was not her husband, Henry, but rather a young courtier named Thomas Culpepper. News of their affair eventually reached Henry, who promptly decided to fetch the garden shears and remove the head of his beloved rose. Upon hearing the bad news, Catherine was understandably upset. She ran to Henry to plead for her life but was stopped by Royal guards and dragged back through the corridors of the palace to her apartments. A few months later both Thomas Culpepper and Catherine Howard were beheaded at the Tower of London.

The ghost of Catherine Howard is said to haunt the corridor down which she was dragged against her will. By the turn of the last century this area of the palace had become associated with a whole host of ghostly experiences, including sightings of a “woman in white” and reports of inexplicable screams.

In January 2001, a palace official telephoned me, explained that there had been a recent surge in Catherine-Howard-related phenomena, and wondered whether I might be interested in investigating. Eager to use the opportunity to discover more about hauntings, I quickly put together an experiment, assembled a research team, photocopied hundreds of blank questionnaires, loaded up my car, and headed off to the palace for a five-day investigation (Wiseman et al. 2002, 2003).

The palace had called a press conference to announce the start of my study, attracting the attention of journalists from all around the world. We decided to make the press conference a two-part affair, with a palace official talking about the history of the haunting in the first half, a brief break, and then my good self describing the forthcoming investigation. A palace historian kicked off the proceedings by telling a packed room of reporters what happened when Henry met Cathy.

During the brief break, I stepped outside to get some fresh air. The strangest thing happened: A car containing two tipsy teenagers drove slowly past me. One of the teenagers rolled down the window and threw an egg at me. The egg smashed on my shirt. Unable to change, I tried to remove the worst of the stains and then returned to the press conference. A few minutes into my talk, one of the journalists noticed the marks on my shirt and, assuming that it was ectoplasm, asked whether Catherine Howard had already slimed me. I replied, “Yes. This is going to be a tougher investigation than I first thought.” Although said in jest, my comment was to prove prophetic.

Prior to the experiment, I had asked the palace to supply me with a floor plan of the corridor that would have held such unpleasant memories for Catherine Howard. I then met with Ian Franklin, a palace warder who had carefully catalogued a century of reports of unusual phenomena experienced by staff and visitors, whom I asked to secretly place crosses on the floor plan to indicate where people had consistently reported their experiences. To avoid any possible bias during the investigation, neither I nor any other member of the research team knew which areas had been marked by Franklin.

During the day, groups of visitors were transformed into ghost hunters. After hearing a brief talk about the project, each participant was handed a blank floor plan and asked to wander along the corridor and place an “X” on the floor plan to indicate the location of any unusual experiences that they might have (essentially playing a game of “spot the ghoul”). Each night we would place a variety of sensors and a £60,000 ($100,300) heat imager in the corridor in the hope of catching Catherine mid-“boo!”

Day one of the investigation went badly, with several participants wandering into the wrong corridor and then wondering why the floor plan was so wildly inaccurate. On day two, we were joined by a woman who claimed to be the reincarnation of Catherine Howard and said that she could provide a unique first-person perspective on the proceedings (“Actually, I was dragged up the corridor, not down it”; “Not sure that the new paint job in the kitchens works for me,” etc.). Day four turned out to be especially interesting. The team (which now included the reincarnated Catherine Howard) assembled in the morning as usual and reviewed the heat sensor data from the previous night. It was immediately obvious that something very strange had taken place, with the graphs showing a massive spike in temperature around 6 AM. We eagerly rewound the recording from the thermal imager to discover whether we had caught Catherine on tape. At dead-on 6 AM the doors at one end of the corridor burst open, and in walked a figure. The reincarnated Catherine Howard instantly recognized the figure as a member of Henry VIII’s court. However, a few seconds later the proceedings took a decidedly more skeptical turn when we saw the figure walk over to a cupboard, remove a vacuum cleaner, and start to clean the carpets. Thankfully, the data from the rest of the investigation proved more revealing.

People who believed in ghosts experienced significantly more strange sensations than the skeptics. Interestingly, we have obtained the same pattern of findings in several investigations at other supposedly haunted locations. Time and again those who believe in the paranormal experience more ghosts than those who don’t. As I loaded my equipment back into my car and said goodbye to our well-meaning but intensely annoying Catherine Howard wannabe, one question nagged away in my mind: Why?

The Machine in the Ghost

Neuropsychologist Michael Persinger, of Laurentian University in Canada, believes that ghostly experiences are caused by the brain malfunctioning and, more controversially, that these sensations can be easily elicited by applying very weak magnetic fields to the outside of the skull (Cook and Persinger 1997, 2001).

In a typical Persinger study, participants are led into a laboratory and asked to sit in a comfortable chair. They then have a helmet placed on their heads, are blindfolded, and are asked to relax for about forty minutes. During this time several solenoids hidden in the helmet generate extremely weak magnetic fields around the participant. Sometimes these fields are focused over the right side of the head; at other times they switch to the left, and once in a while they circle around the skull. Finally the helmet and blindfold are removed, and the participant is asked to complete a questionnaire indicating whether he or she experienced any strange sensations, such as the sense of a presence, vivid images, odd smells, being sexually aroused, or coming face-to-face with God.

After years of experimentation, Persinger claims that around 80 percent of participants tick the “yes” box to at least one of these experiences, with some even going for the “all of the above” option. The study has been featured in many science documentaries, resulting in several presenters and journalists putting Persinger’s magic helmet on their heads in the hope of meeting their maker. For the most part, they have not been disappointed. Psychologist Susan Blackmore, for example, felt as if something had gotten hold of her leg and dragged it up the wall, followed by a sudden sense of intense anger (which is exactly how I would feel if someone took my leg and dragged it up a wall).

All was going well with Persinger’s theory until a team of Swedish psychologists, led by Pehr Granqvist from Uppsala University, decided to carry out the same type of experiments (Granqvist et al. 2005; Larsson et al. 2005). (For additional information about this work, see www.nature.com/news/2004/041206/full/news041206-10.html.)

It all started well, with some of the Swedes visiting Persinger’s laboratory and even borrowing a portable version of one of his helmets for their own study. However, Granqvist became worried that some of Persinger’s participants may have known what was expected of them, and their experiences could therefore have been due to suggestion rather than the subtle magnetic fields. To rule out this possibility in his own work, Granqvist had all of his participants wear Persinger’s borrowed helmet but ensured that the coils were turned on for only half of the participants. Neither the participants nor the experimenters knew when the magnetic fields were on and when they were off.

The results were remarkable. Granqvist discovered that the magnetic fields had absolutely no effect. Three of his participants reported intense spiritual experiences, but two of these were not being exposed to the magnetic fields at the time. Likewise, twenty-two people reported more subtle experiences, but the coils were turned off for eleven of them. When Granqvist’s work was published in 2004, Persinger argued that the poor showing may have been due, in part, to the fact that the participants who had their helmet coils turned on were exposed to the magnetic fields for only fifteen minutes and to the fact that Granqvist ran the DOS-based software controlling the coils in Windows and thus possibly altered the nature of the magnetic fields. The Swedish team defended their work and stood by their findings.

The idea of electromagnetic spirits has caught the imagination of the media and public alike. However, the scientific jury is unconvinced. So has anyone solved the mystery of hauntings? Before we delve deeper, it is time to discover more about the power of suggestion.

The Subtle Hint of Silage

In the late 1970s, sensory scientist Michael O’Mahony from the University of California took the power of suggestion to new heights when he persuaded the BBC to undertake an ingenious version of his well known sensory study during a live program (O’Mahony 1978). O’Mahony constructed some mock scientific apparatus (think a large weird-looking cone, masses of wires, and several oscilloscopes) and managed to keep a straight face as he told viewers that this newly devised “taste trap” used “Raman Spectroscopy” to transmit smells via sound. He then proudly announced that the stimulus would be a country smell. Unfortunately, the studio audience interpreted his comments to mean the smell of manure, resulting in a significant amount of laughter. After clarifying that they would not be broadcasting the smell of cow shit into people’s homes, the research team played a standard Dolby tuning tone for ten seconds. Just as the bottles in the more pedestrian versions of O’Mahony’s study contained nothing but water, so the tone did not actually have the ability to induce smells.

Viewers were then asked to contact the television station and describe their experiences. A few hundred viewers responded, with the majority stating that they had detected a strong smell of hay, grass, or flowers. Although they were explicitly told that the smell would not be manure-related, several people mentioned that they had detected the subtle hint of silage. Many respondents described how the tone had brought about more dramatic symptoms, including hay fever attacks, sudden bouts of sneezing, and dizziness.

The “Raman Spectroscopy” was simply scientific mumbo-jumbo. In reality the experimenters were exploring how the power of suggestion can cause people to experience various smells. James Houran (of Internet dating and ghost-busting fame) also believes that suggestion may play a vital role in unlocking the mystery of hauntings.

Houran speculated that if suggestible people believe that they are in a haunted house, they may experience the strange sensations typically attributed to ghostly activity. In addition, he noted that those experiences are likely to create a feeling of fear that will cause people to become hyper-vigilant and pay attention to the subtlest of signals (Lange and Houran 1999). They will suddenly notice that tiny creak in the floorboards, the swaying of the curtains, or a brief whiff of burning. All of this will cause them to become even more afraid and therefore exhibit even greater hyper-vigilance. The process feeds on itself until the person starts to become highly agitated, anxious, and prone to more extreme sensations and hallucinations.

Findings from many studies support Houran’s ideas. In my own work, those who believed in ghosts reported far more weird experiences than skeptics, and their sensations tended to focus on the type of scary-looking locations that are frequently featured in horror films. Although these findings are encouraging, the ultimate testing of the theory involves taking suggestible people to a place that does not have a reputation for being haunted, making them believe that it does, and seeing if they experience the same kind of ghostly activity reported in “genuine” hauntings. Houran has conducted several of these experiments with intriguing results.

In one experiment he took over a disused theater that had absolutely no reputation for being haunted and asked two groups of people to walk around it and report how they felt (Lange and Houran 1997). Houran told one group that the theater was associated with ghostly activity and the other that the building was simply undergoing renovation. Those in the “this building is haunted” group reported all sorts of weird sensations, while the other group experienced nothing unusual. In another study, Houran asked a married couple living in a house that had no reputation for ghostly activity to spend a month making note of any “unusual occurrences” that they noticed in their home (Houran and Lange 1996). Reporting the results in the paper “Diary of Events in a Thoroughly Unhaunted House,” he noted that the couple reported an amazing twenty-two weird events, including the inexplicable malfunctioning of their telephone, their name being muttered by a ghostly presence, and the strange movement of a souvenir voodoo mask along a shelf.

Hauntings do not require genuine ghosts, underground streams, low frequency sound waves, or weak magnetic fields. Instead, all it takes is the power of suggestion.

Ghosts, Gods, and Goblins

Although the psychology of suggestion accounts for many ghostly phenomena, there still exists one final mystery—why on earth should our sophisticated brains have evolved to detect nonexistent ghostly entities?

Scientists have proposed various theories to account for what goes bump in our minds. Psychologist Jesse Bering (2006) from the University of Arkansas has suggested that both ghosts and God help forge a more honest society by convincing people that they are constantly being watched. Bering and his team tested their idea by carrying out a somewhat strange experiment. In their study, students were asked to complete an intelligence test. The test had been carefully constructed to ensure that the students could cheat if they wanted to, and the experimenters could secretly monitor each person’s level of deception. Just before taking the test, a randomly selected group of students was told that the test room was apparently haunted. As predicted by the “ghosts make people more honest” theory, the students who thought that they were in a haunted room were far less likely to cheat on the test.

However, perhaps the most popular theory to account for the evolution of ghostly experiences concerns the “Hypersensitive Agency Detection Device” (Barrett 2004). Oxford University psychologist Justin Barrett believes that the idea of “agency”—being able to figure out why people act the way they do—is essential to our everyday interactions with one another. In fact, it is so important that Barrett thinks the part of the brain responsible for detecting such agency often goes into overdrive, causing people to see human-like behavior in even the most meaningless stimuli.

In the 1940s, psychologists Fritz Heider and Mary-Ann Simmel conducted a now-classic experiment that provides a beautiful illustration of Barrett’s point. Heider and Simmel created a short cartoon animation in which a large triangle, a small triangle, and a circle moved in and out of a box. They then showed the meaningless cartoon to people and asked them to describe what was happening. Most people instantly created elaborate stories to explain the cartoon, saying, for example, that perhaps the circle was in love with the little triangle, and the big triangle was attempting to steal away the circle but the little triangle fought back, and the small triangle and circle eventually lived happily ever after.

In short, people saw agency where none existed. Barrett believes that the same concept helps explain gods, ghosts, and goblins. According to the theory, many people are very reluctant to think that certain events are meaningless, and they are all too eager to assume that the events are the work of invisible entities. They might, for instance, experience an amazing stroke of good luck and assume it is angels at work, be struck down with an illness and see it as evidence of demons, or hear a creaking door and attribute it to a ghostly woman in white. If Barrett is right, ghosts are not the result of superstitious thinking. Neither are they spirits returning from the dead. Instead, they are simply the price we pay for having remarkable brains that can effortlessly figure out why other people behave the way they do. As such, ghosts are an essential part of our everyday lives.

On Publishing Paranormality

All of my previous books have been produced by large American publishing houses. However, when it came to my new book, Paranormality (www.paranormalitybook.com), the situation was different. Many major publishers were convinced that there simply isn’t a market for a skeptical book about the paranormal. When no serious offers came forward, I decided to take a bold step. I will publish the unashamedly skeptical Paranormality as an e-book in America and have my U.K. publisher ship physical copies of the British book to the United States. It is a daring experiment, and I have no idea how it will work out. I don’t have the large-market budget and connections of a large publishing house. However, I hope that I will have the support of the skeptical movement and anyone else who cares about science. Psychic hotlines and television shows are a multi-million dollar business. Many people do not want the American public to read books like Paranormality. For that reason alone, I believe that they deserve the largest audience possible.

References

Barrett, J.L. 2004. Why Would Anyone Believe in God? United Kingdom: AltaMira Press.

Bering, J.M. 2006. The cognitive psychology of belief in the supernatural. American Scientist 94: 142–49.

Cook, C.M., and M.A. Persinger. 1997. Experimental induction of the ‘sensed presence’ in normal subjects and an exceptional subject. Perceptual and Motor Skills 85: 683–93.

———. 2001. Geophysical variables and behavior: XCII. Experimental elicitation of the experience of a sentient being by right hemispheric, weak magnetic fields: Interaction with temporal lobe sensitivity. Perceptual and Motor Skills 92: 447–48.

Granqvist, P., M. Fredrikson, P. Unge, et al. 2005. Sensed presence and mystical experiences are predicted by suggestibility, not by the application of weak complex transcranial magnetic fields. Neuroscience Letters 379: 1–6.

Houran, J., and R. Lange. 1996. Diary of events in a thoroughly unhaunted house. Perceptual and Motor Skills 83: 499–502.

Lange, R., and J. Houran. 1997. Context-induced paranormal experiences: Support for Houran and Lange’s model of haunting phenomena. Perceptual and Motor Skills 84: 1455–58.

———.1999. The role of fear in delusions of the paranormal. Journal of Nervous and Mental Disease 187: 159–66.

Lange, R., J. Houran, T.M. Harte, et al. 1996. Contextual mediation of perceptions in hauntings and poltergeist-like experiences. Perceptual and Motor Skills 82: 755–62.

Larsson, M., D. Larhammar, M. Fredrikson, et al. 2005. Reply to M.A. Persinger and S.A. Koren’s response to Granqvist et al. ‘Sensed presence and mystical experiences are predicted by suggestibility, not by the application of transcranial weak magnetic fields.’ Neuroscience Letters 380: 348–50.

Musella, D.P. 2005. Gallup poll shows that Americans’ belief in the paranormal persists. Skeptical Inquirer 29(5): 5.

O’Mahony, M. 1978. Smell illusions and suggestion: Reports of smells contingent on tones played on television and radio. Chemical Senses and Flavour 3: 183–89.

Wiseman, R., C. Watt, E. Greening, et al. 2002. An investigation into the alleged haunting of Hampton Court Palace: Psychological variables and magnetic fields. Journal of Parapsychology 66(4): 387–408.

Wiseman, R., C. Watt, P. Stevens, et al. 2003. An investigation into alleged “hauntings.” The British Journal of Psychology 94: 195–211

After more than sixty years of experimentation, researchers have failed to reach a consensus about the existence of psi (psychic ability). Some argue that there exists overwhelming evidence either for or against the psi hypothesis, while others believe that it simply isn’t possible to answer the question one way or the other. One of the main obstacles to closure on the psi question involves the way in which null results are viewed (Alcock 2003). Many parapsychologists have adopted a “heads I win, tails you lose” approach to their work, viewing positive results as supportive of the psi hypothesis while ensuring that null results do not count as evidence against it.

Cherry-Picking New Procedures

Parapsychologists frequently create and test new experimental procedures in an attempt to produce laboratory evidence for psi. Most of these studies do not yield significant results. However, rather than being seen as evidence against the existence of psychic ability, such null findings are usually attributed to the experiment being carried out under conditions that are not psi-conducive. They are either never published (the “filedrawer effect,” see Douglas M. Stokes, “The Shrinking File­drawer,” SI, May/June 2001) or are quietly forgotten even if they make it into a journal or conference proceeding. Once in a while one of these studies produces significant results. Such studies frequently contain potential methodological artifacts, in part because they are using new procedures that have yet to be scrutinized by the research community. In addition, the evidential status of these positive findings is problematic to judge because they have emerged from a mass of nonsignificant studies. Nevertheless, they are more likely than nonsignificant studies to be presented at a conference or published in a journal, usually viewed by proponents as tentative evidence for psi, acting as a catalyst for further work.

To my knowledge, only one paper has revealed an insight into the potential scale of this problem. Watt (2006) summarized all of the psi-related final-year undergraduate projects that have been supervised by staff at Edinburgh University’s Koestler Parapsychology Unit between 1987 and 2007. Watt tracked down thirty-eight projects, twenty-seven of which predicted overall significant performance on a psi task with the remainder predicting significant differences between experimental conditions. The work examined a range of new and established procedures, including, for example, dowsing for a hidden penny, the psychokinetic control of a visual display of a balloon being driven by a fan onto spikes, presentiment of photographs depicting emotional facial expressions, detecting the emotional state of a sender in a telepathy experiment, ganzfeld studies, and card guessing. Interestingly, Watt’s paper also demonstrated a reporting bias. Only seven of the thirty-eight studies had made it into the public domain, presented as papers at conferences held by the Parapsychological Association. All of these papers had predicted overall significant performance on the psi task. There was a strong tendency for parapsychologists to make public those studies that had obtained positive findings, with just over 70 percent (five out of seven) of the studies presented at conferences showing an overall significant result, versus just 15 percent (three out of twenty) of those that remained unreported. Watt’s analysis, although informative, underestimates the total number of psi-related studies undertaken at Edinburgh University because it did not include projects undertaken by students prior to their final year, experiments run by postgraduate students and staff, or any work conducted before 1987. Multiply these figures by the number of parapsychologists who have conducted and supervised psi research across the world over the last sixty years or so, and the scale of the issue becomes apparent.

Explain Away Unsuccessful Attempted Replications

If a procedure seems to yield significant psi effects, additional follow-up studies using that procedure are conducted. Although these additional studies occasionally take the form of strict replications, they usually involve some form of variation. If these follow-up studies obtain significant results, they are often the subject of considerable debate: proponents argue that the findings represent evidence of psi, and skeptics scrutinize the work for possible methodological and statistical shortcomings. However, any failure to replicate can be attributed to the procedural modifications rather than to the nonexistence of psi. Perhaps the most far-reaching version of this “get out of a null effect free” card involves an appeal to the “experimenter effect,” wherein any negative findings are attributed to the psi-inhibited nature of the parapsychologist running the study.

This nullifying of null findings permeates parapsychological literature. For example, Kanthamani and Broughton (1994) report a large-scale attempt to replicate the alleged ganzfeld telepathy effect, wherein one participant (referred to as a receiver) experiences a mild form of sensory deprivation and is then asked to identify a target being viewed by another person (a sender) in a distant location. Parapsychologists have employed various types of targets in these experiments, including photographs and drawings (static targets) and video clips (dynamic targets). In the studies described by Kanthamani and Broughton, the target material consisted of randomly chosen pictures (mainly postcard-sized art prints). The project involved a huge amount of work: researchers ran a series of experiments over a six-year period and conducted more than 350 individual ganzfeld sessions. The studies yielded a nonsignificant cumulative effect. However, Kanthamani and Broughton spent no time discussing whether this null finding might act as evidence against the psi hypothesis and instead simply concluded that “it is probably safe to say that static picture targets remain a less than ideal choice for ganzfeld experiments.”

Once again, this process represents the “heads I win, tails you lose” principle. Successful replications are seen as evidence of psi, while null results are attributed to the non-psi-conducive conditions under which the replication was carried out.

Data Mining

In addition to explaining away null findings via allegedly failed procedural modifications, some parapsychologists also adopt an “any anomaly will do” attitude and data mine in an attempt to produce some kind of psi-related result. Although such post hoc data mining might help guide future work, it has little if any evidential value. Nevertheless, parapsychologists often present it as tentative evidence in support of the psi hypothesis.

Willin’s (1996) description of his ganzfeld psi studies presents a striking example of this process at work. Willin conducted one hundred ganzfeld sessions over a fifteen-month period, taking the unusual step of using musical clips as targets. The study obtained a nonsignificant result. However, rather than explore whether this null finding counts as evidence against the psi hypothesis, Willin conducted a series of post hoc analyses, exploring, for example, the relationship between participants’ psi scores and their age, profession, hobbies, previous paranormal experiences, and relationship with the person acting as the sender. Additional analyses explored psi scoring as a function of the month and time of day each trial was conducted. Most of these analyses yielded inconclusive results, but Willin eventually found that trials conducted early in the experiment obtained a higher hit rate than those conducted later and suggested that this might have been due to “less interest being shown by the Receivers and the Senders or by an unintentional goat effect being displayed by the Experimenter.”

This type of data mining again shows the “heads I win, tails you lose” principle in action, with any null effects being nullified by the apparent discovery of post hoc findings.

Meta-Analyses and Retrospective Data Selection

After several studies have been conducted using a new procedure, parapsychologists usually carry out some form of meta-analytic review of the work. If the combined outcome of the studies is significant, the meta-analysis is usually the subject of considerable debate, with proponents believing that the finding represents evidence of psi and skeptics arguing that it may have a normal explanation (including, for example, publication bias, inappropriate inclusion criteria, and poor methodology). However, if the cumulative effect is nonsignificant, parapsychologists often attribute this null effect to the non-psi-conducive procedural variations described in the preceding section.

Perhaps more important, the procedurally heterogeneous collection of studies usually presents parapsychologists with an opportunity to “explain away” overall null effects by retrospectively identifying a subset of studies that used a certain procedure and yielded a significant cumulative effect.

A striking illustration of this occurred in the late 1990s during a meta-analytic debate surrounding the ganzfeld psi studies. In 1999, Milton and Wiseman published a meta-analysis of all ganzfeld studies that were begun after 1987 and published by the start of 1997, and they noted that the cumulative effect was both small and nonsignificant (Milton and Wiseman 1999). Some parapsychologists criticized this analysis, arguing that they had included all of the ganzfeld studies conducted during this period and that they should have instead focused on those that had employed a “standard” procedure developed by parapsychologist Charles Honorton and his colleagues during a seminal set of ganzfeld studies conducted at the Psychophysical Research Laboratory (PRL) in the late 1980s. The difficulties with this approach became clear when researchers were unable to settle on what would constitute a “standard” set of procedures (Schmeidler and Edge 1999). Eventually, Bem, Palmer, and Broughton (2001) set out to tackle this issue experimentally, asking several people to rate the degree to which the studies in our analysis had employed Honorton’s “standard” ganzfeld procedure and then correlating their ratings against the effect size of each study. Rather than provide their own description of this “standard” procedure, Bem, Palmer, and Broughton had the raters read relevant sections in two previous papers describing the PRL studies. However, they also added a series of additional conditions, informing their raters, for example:

You should treat as standard the use of artistic or creative subject samples (as one of the most successful components of the PRL experiments used such a sample) or subjects having had previous psi experiences or having practiced a mental discipline such as meditation (as such subjects were shown to be the best scorers in the PRL experiments).

The addition of participant selection as an allegedly “standard” condition was not mentioned in the method section of either of the papers describing the PRL work. As such, it could be seen as an excellent example of retrospective data fitting, wherein parapsychologists decide which studies to analyze (or, in this instance, the weight assigned to them) on the basis of their known outcome.

Once again, it’s the “heads I win, tails you lose” principle. A significant overall effect is seen as evidence for psi while a null effect initiates post hoc searching for pockets of significance.

Decline Effects and Jumping Ship

The alleged psi effects associated with a certain procedure frequently have a curious habit of fading over the course of repeated experimentation. Skeptics argue that this is due to the parapsychologists identifying and minimizing potential methodological and statistical flaws over time. However, some parapsychologists have come up with creative ways of explaining away this potential threat, arguing that such decline effects are either an inherent property of psi or that psychic ability really does exist but is inversely related to the level of experimental controls employed in a study (see Kennedy 2003 for a review of this approach).

The decrease in alleged psi often causes some parapsychologists to abandon ship in search of a new procedure, placing them back at square one, ready to repeat history. This is not a new observation. For example, writing over thirty years ago, parapsychologist Joseph Gaither Pratt noted:

One could almost pick a date at random since 1882 and find in the literature that someone somewhere had recently obtained results described in terms implying that others should be able to confirm the findings.... One after another, however, the specific ways of working used in these initially successful psi projects have fallen out of favor and faded from the research scene—except for the latest investigations which, one may reasonably suppose, have not yet had enough time to falter and fade away as others before them have done. (Pratt 1978)

This constant “ship jumping” is one of the defining features of psi research, with new paradigms emerging every decade or so. Take, for example, the different trends in ESP research that have emerged over the years. Initial work, conducted between the early 1930s and late 1950s, primarily involved card guessing experiments in which people were asked to guess the identity of specially printed playing cards carrying one of five simple symbols. By the mid-1960s parapsychologists had realized that such studies were problematic to replicate and so turned their attention to dream telepathy and the possibility of participants predicting the outcome of targets selected by machines. In the mid 1970s and early 1980s, the ganzfeld experiments and remote viewing took over as dominant paradigms. In 1987, a major review of the area by parapsychologists K. Ramakrishna Rao and John Palmer argued that two sets of ESP studies provided the best evidence for the replicability of psi: the ganzfeld experiments and the differential ESP effect (wherein participants apparently score above chance in one condition of an experiment and below chance in another). More recently, parapsychologists have shifted their attention to alleged presentiment effects, wherein participants appear to be responding to stimuli before they are presented. Finally, there are now signs that the next new procedure is likely to adopt a neuropsychological perspective, focusing on EEG measurements or functional MRI scans as people complete psi tasks.

Conclusion

Parapsychologists have tended to adopt a “heads I win, tails you lose” approach to their work, viewing positive results as supportive of the psi hypothesis while ensuring that null results do not count as evidence against it. This involves cherry-picking new procedures from a mass of chance results, varying any allegedly “successful” procedures and then blaming these variations for any lack of replication, searching for pockets of post hoc significance whenever a meta-analysis produces a null result, explaining away decline effects as an inherent property of psi, and finally jumping to the next new promising procedure. This giddy process results in an ambiguous dataset that, just like the classic optical illusion of the old hag and attractive young woman, never contains enough information to allow closure in one direction or the other.

To help the field move forward and rapidly reach closure on the psi question, parapsychologists need to make four important changes in the way they view null findings. First, they should stop trying lots of new procedures and cherry-picking those that seem to work and instead identify one or two that have already yielded the most promising results. Second, rather than varying procedures that appear successful, they should instead have a series of labs carry out strict replications that are both methodologically sound and incorporate the most psi-conducive conditions possible. Third, researchers should avoid the temptation for retrospective meta-analysis by pre-registering the key details involved in each of the studies. And finally, researchers need to stop jumping ship from one experimental procedure to another and instead have the courage to accept the null hypothesis if the selected front-runners don’t produce evidence of a significant and replicable effect.

I hope that this process will help consign the psi debate to the history books and parapsychologists will no longer find themselves sitting on the fence arguing the “there is enough evidence to justify further work but not enough to conclude one way or the other” position. Rather than nullify null results, experimenters should be brave enough to give it their best shot and finally discover whether psi actually exists.

References

• Alcock, J.E. 2003. Give the null hypothesis a chance: Reasons to remain doubtful about the existence of psi. In Psi Wars: Getting to Grips with the Paranormal, ed. J. Alcock, J. Burns, and A. Freeman, 29–50. Charlottes­ville, VA: Imprint Academic.
• Bem, D.J., J. Palmer, and R.S. Broughton. 2001. Updating the ganzfeld database: A victim of its own success? Journal of Parapsychology 65: 207–218.
• Kennedy, J.E. 2003. The capricious, actively evasive, unsustainable nature of psi: A summary and hypotheses. Journal of Parapsychology 67: 53–74.
• Kanthamani, H., and R.S. Broughton. 1994. Institute for Parapsychology ganzfeld-ESP experiments: The manual series. Proceedings of Presented Papers: The Parapsychological Association 37th annual convention, 182–189.
• Milton, J., and R. Wiseman. 1999. Does psi exist? Lack of replication of an anomalous process of information transfer. Psychological Bulletin 125: 387–391.
• Pratt, J.G. 1978. Prologue to a debate: Some assumptions relevant to research in parapsychology. The Journal of the American Society for Psychical Research 72: 127–139.
• Rao, K.R., and J.R. Palmer. 1987. The anomaly called psi: Recent research and criticism. Behavioral and Brain Sciences 10: 539–51.
• Schmeidler, G.R., and H. Edge. 1999. Should ganzfeld research continue to be crucial in the search for a replicable psi effect? Part II. Edited ganzfeld debate. Journal of Parapsychology 63: 335–388.
• Watt, C. 2006. Research assistants or budding scientists? A review of 96 undergraduate student projects at the Koestler Parapsychology Unit. Journal of Parapsychology 70: 335–356.
• Willin, M. J. 1996. A ganzfeld experiment using musical targets. Journal of the Society for Psychical Research 61: 1–17.

It would be nice to think that viewers are canny enough to realize that such shows contain considerably more fiction than fact and that they might use their precognitive powers to hit the “off” button on their TV controllers before the programs begin. Unfortunately, research suggests that a significant percentage of the public really does believe that such programming depicts genuine paranormal events and thus comes away more convinced than ever about the existence of such phenomena. Perhaps because of this, various official bodies and pressure groups have urged those producing such shows to act responsibly. The Committee for Skeptical Inquiry’s Council for Media Integrity has suggested that certain paranormal programming should carry “entertainment” or “fiction” labels. Likewise, the British media regulatory body Ofcom notes that any demonstrations of paranormal phenomena “… that purport to be real (as opposed to entertainment) must be treated with due objectivity” and that if a demonstration is for entertainment purposes, “this must be made clear to viewers.”

Program creators and broadcasters usually attempt to comply with such guidelines by presenting onscreen “disclaimers,” essentially informing viewers that such shows may not be exactly as they appear and thus should only be taken seriously by the hard of thinking. However, such messages are often shown for a very short period of time and tend to contain long and rather tortuously worded messages displayed in a relatively small font. Although such disclaimers may satisfy legal and regulatory guidelines, we wondered whether they had any real psychological impact on viewers. We hypothesized that if people genuinely believed that a program containing seemingly impossible phenomena was developed to entertain rather than inform, then they should be less likely to believe that the phenomena shown constitute evidence for the paranormal. But do the types of disclaimers typically used actually affect the way people view the evidential nature of the phenomena shown?

To help find out, we conducted an initial study. We recorded a ten-minute segment from a well-known television show in which an alleged medium gave readings to various audience members. The clip ended with an eighty-word disclaimer explaining that the show should be seen as entertainment, that people varied in their opinions about the nature of alleged mediumistic abilities, and that the program content should not be construed as fact. This long paragraph was broadcast in relatively small type and remained on the screen for about ten seconds.

We showed the clip to a group of undergraduate psychology students and asked them to rate the degree to which they thought the program provided evidence of “paranormal” powers, using a scale ranging from 1 (strongly disagree) to 7 (strongly agree). Next, we created a second clip by editing out the disclaimer altogether, showed this clip to another group of students, and had them make the same ratings. There was no statistically significant difference between the two groups’ ratings, suggesting that the disclaimer had no effect on the way in which the students perceived the paranormal content of the program.¹

We wondered whether the lack of any effect was due to the disclaimer being shown at the end of the program. After all, participants had probably made up their minds about the alleged paranormal phenomena by then, and the near-subliminal presentation of the long paragraph was unlikely to influence them one way or another. To test this idea, we edited the clip yet again, this time placing the disclaimer at the start of the show. This new edit was shown to another group of students, who again went on to rate the degree to which it provided evidence of paranormal powers. The results? Once again, there was no significant difference between their ratings and the ratings of those who didn’t see the disclaimer.²

Undaunted, we toyed with the notion that perhaps the disclaimer was simply too vague and so produced our own shorter, more strongly worded, version:

The alleged mediumistic abilities of the individuals featured in this program have not been subjected to controlled scientific investigations. In addition, some scientists have suggested that anecdotal evidence in support of such abilities could be due to several psychological techniques, such as use of general statements and feedback from people’s verbal and non-verbal behaviour.

Once again, this was placed onscreen for ten seconds. We showed this version to two more groups of students, with one group seeing it before the show and another after. Did this have any effect? No. Once again, there was no statistical difference between the ratings of these groups and the ratings of those that saw no disclaimer at all.³

At present, we don’t know why the type and position of the disclaimers tested have no significant effect on the way in which people view the evidential nature of the alleged paranormal phenomena in the program. It could be, for example, that our participants couldn’t be bothered to read the disclaimer or that any influence it had was outweighed by the much more dramatic material in the rest of the clip. Either way, the results suggest that there is a pressing need to develop a form of wording and presentation that really gets the message across. Until then, the situation remains grim. Next time you see a paranormal program briefly presenting one of those long “for entertainment only” disclaimers you might be tempted to think, “Oh well, I guess it’s better than nothing.” Our research suggests that you are wrong.

Notes

1. Original disclaimer at end (N=25), mean evidentiality rating = 2.71; no disclaimer (N=25) mean evidentiality rating = 2.59; t(51df) = .255, p = .80.
2. Original disclaimer at start (N=29), mean evidentiality rating = 2.59, t(54df) = .014, p = .99.
3. New disclaimer at start (N=31), mean evidentiality rating = 2.83, t(57) = .510, p = .61; new disclaimer at end (N=26), mean evidentiality rating = 3.2, t(52df) = 1.247, p = .22.

Around the turn of the last century, theatergoers could enjoy many different forms of entertainment, including drama, music, comedy, and . . . wait for it . . . science shows. Surprising as it may now seem, leading scientists of the day were prepared to take off their lab coats, put on some greasepaint, and tread the boards. Packed houses would watch in awe as these learned men demonstrated the very latest scientific advances, including electrical wonders, amazing chemical reactions, and the marvels of magnetism. Unfortunately, this heady mixture of entertainment and science didn’t stand the test of time, and within a few years the scientific showmen found themselves out of the limelight and back in the less glamorous world of lecture theaters and public halls.

Fast-forward about a century or so to late 2001, when I received a telephone call from science writer Simon Singh. Simon and I first met about ten years ago when we worked together on an episode of the well-known BBC television science program Tomorrow’s World. Simon had called to ask if I was interested in being involved in a joint project. He thought it would be fun for us to turn back the hands of time and co-present a science show at a London theater. I was initially skeptical for two reasons. First, it wasn’t my idea. Second, I wasn’t convinced that the latest discoveries in physics and mathematics would really hold the attention of a modern audience. Sure, there were lots of successful science shows for children, and even some aimed at family audiences, but Simon wanted to move beyond that. He was eager to reach regular theatergoers, essentially asking them to choose science over Shakespeare. The challenge seemed considerable, but it was an interesting idea, and I agreed to be involved.

Simon persuaded The National Endowment for Science, Technology, and the Arts (NESTA) to fund the project, and he invited theater director Portia Smith to help create the show. After much deliberation, we settled upon the title Theatre of Science, and set about finding an off-West End venue in London. Our initial approaches were met with a dispiriting mixture of disbelief and skepticism, with several theater managers telling us that a science show simply wouldn’t attract an audience. However, persistence paid off, and we eventually found a venue willing to host the show. The Soho Theatre is located in the heart of London’s theater district, and has forged a considerable reputation for staging unusual and cutting edge performances. The Soho’s manager liked the idea of taking science out of the lab and onto the stage and offered us a run at his theater.

After a few days of rehearsal, the show started to take shape. The first half involved Simon illustrating various aspects of probability theory by demonstrating gambling scams and undertaking bets with members of the audience. After a short interval, I explored the psychology of deception and lying with the help of magic tricks and optical illusions. Strictly adhering to a “show don’t tell” principle, rule, both halves involved as much audience interaction as possible. For example, when discussing the efficacy of lie detectors, we hooked up an audience member to a polygraph and projected that person’s physiological data live onto a large screen as he attempted to deceive the audience. We also thought it a good idea to inject some comedy into the proceedings. Simon started off the show by using mathematics to “prove” that the Teletubbies are evil, and undermined The Bible Code by pointing out that the same principles can be used to demonstrate how the death of Diana Princess of Wales was “predicted” within the pages of Moby Dick. We also made a conscious decision to construct a show that was decidedly low-tech, simply equipping ourselves with an overhead projector, some acetates, and a couple of marker pens. We ditched the idea of any staging, including wings or sophisticated lighting plots, and chatted with the audience as they walked into the auditorium. This low-tech approach to staging seemed appropriate. Science is all about trying to discover how the world really works, and so it seemed appropriate to remove the various theatrical devices usually employed to help an audience suspend disbelief and instead present the show in a far more straightforward way.

We opened at The Soho Theatre in March 2002. The idea of two academics venturing onto a West-End stage armed with just a few acetates and a couple of theories attracted the attention of the media, and the show received considerable press and radio coverage. As a result, our initial run quickly sold out and the theater was happy to add some additional dates. The performances drew a strong response from both the audience and reviewers alike. One newspaper, The Evening Standard, wrote that the show “almost makes academia sexy” and described it as “a unique masterclass on the mind.” Similarly, What’s On magazine called it “an uplifting, thought-provoking and frequently hilarious alternative to the usual theatre fare.” Perhaps more important, feedback forms indicated that about half of the audience had absolutely no background in science, nor had attended any previous science-based event. The show was taking science to this new audience simply by being performed in an accessible way within a theatrical context. One online review underlined this point, noting, “Don’t fear the men in white coats, this is an entertaining hour for even the most scientifically illiterate.”

The Royal Society was kind enough to provide funding for us to take the show up to the Edinburgh Fringe Festival in August 2002, and we again attracted a sell-out audience. Flushed with success, Simon and I did nothing more with the show for a couple of years. Then, in 2005, again supported by NESTA, we decided to stage a more ambitious version of the show back at the Soho Theatre. We devised various new items. For example, each night Simon was given just three minutes to explain the entire history of the universe, and then he demonstrated the concept behind redshift by electrocuting a gherkin.

Part of the expansion process involved bringing other performers on board. A few years earlier, I had worked with Delia Du Sol, one of the U.K.’s top contortionists, on a project exploring the science of anatomy. This work had involved taking MRI scans of Delia as she performed extreme back-bends. During Theatre of Science, we showed these scans to the audience prior to them watching Delia’s performance, in order that they had a much greater understanding of how her unique anatomy allowed her to bend her body into seemingly impossible shapes. We also invited musicians Sarah Angliss and Stephen Wolf to perform the world’s only theremin duet, and explain how electromagnetism allowed the performers to play these unique instruments without touching them.

Richard Wiseman, left, explores the anatomy of contortionist Delia Du Sol, right.

While developing ideas for the show, I came across a quote from magician Harry Houdini, stating that, if a performer wants to guarantee a full house, he or she should simply advertise the fact that a stunt is being performed that may result in death. The words resonated with me, and I started to look around for a genuinely dangerous, but science-based, stunt that could be performed in the intimate setting of the Soho Theatre.

Eventually, I came across HVFX—a company that makes high-voltage electricity equipment for television and stage. I approached them and explained our situation, and technical director Nick Field kindly agreed to put together something for the show. He constructed two rather odd looking metal pillars, known as Tesla coils, capable of generating six-foot bolts of million-volt lightning. HVFX also built a coffin-shaped cage that would go between the coils and absorb the full force of the strikes, assuring us that various thus far incontrovertible laws of physics meant that it was safe to stand inside the cage. As a finale to the show, either Simon or myself entered the coffin-shaped cage and absorbed the full force of the strikes. There was no room for error, as the bolts of lightning were potentially lethal.

The staging of such a dangerous stunt attracted a large amount of media attention, and, once again, we quickly sold out for the entire run. Again we added more nights, and again they too sold out. We proved that science could hold its own against more mainstream forms of theater, and the reviews were positive, with, for example, The Times remarking that “the spirit of Houdini lives on.”

In 2006, we were invited to perform the show for a short run in an off-Broadway theater. Cosponsored by the Center for Inquiry office in New York as part of an arts and science festival being organized by CFI Director Austin Dacey, we boxed up the show and crossed the Atlantic. The Theater For The New City is located in the heart of New York’s East Village district—an area home to several other unusual off-Broadway shows including The Blue Man Group and Stomp. The theater’s cavernous auditorium provided a perfect Frankenstein-like setting for the show and allowed us to crank up the output from the coils.

The hefty construction of our cage had prevented us shipping it to America, and so we had to create a new cage onsite. Unfortunately, obtaining a generator that could produce the power required by the European coils proved surprisingly time-consuming, and so we had precious little time to construct our new “cage of death.” A quick trip to a couple of hardware stores resulted in a stack of six-foot-long metal tubes, a small saw, a roll of thin metal mesh, and a pair of industrial scissors. Simon and I set to work and managed to hastily construct a wobbly-but-workable cage, finishing just fifteen minutes before the opening performance. The curtain went up and we faced our first American audience. Fifty minutes later, with the stage bathed in red light, we moved the cage between the coils, and Simon bravely climbed inside. The coils buzzed into action, and the bolts of lethal lightning slammed into the somewhat shaky structure. Simon emerged alive, and the audience cheered.

It was only later that we discovered that the new cage was potentially far more lethal than the one we had used in Britain. The U.K. cage is constructed from thick copper tubing, making it safe for the performer to touch the inside of the cage. However, the much thinner mesh we had used in the U.S. meant that touching the inside of the cage would, if you excuse the pun, prove to be a shockingly lethal experience.

We played to packed houses, again showing that there is an audience willing to spend a scientific night out at the theater (or watch scientists risk death). We will remember the experience for a long time, not only because of the buzz of taking the first science show off-Broadway, but because night after night, we were a little too close to the one thing that, performers dread—dying on stage.

Five years ago, I fully expected Theatre of Science to be a one-time set of performances that would not do especially well. I am happy to admit that I was wrong. There is an audience for science. It is all a question of presenting it in the right way. A century ago, some of the world’s leading scientists took to the stage to educate and excite the public about their work. Our experiences suggest that they were onto something, and our hope is that other academics will now step into the limelight and continue the tradition that is theater of science.

Schwartz, Russek, Nelson, and Barentsen (2001) recently reported two studies in which mediums appeared to be able to produce accurate information about the deceased under conditions that the authors believed “eliminate the factors of fraud, error, and statistical coincidence.” Their studies were widely reported in the media as scientific proof of life after death (e.g., Matthews 2001; Chapman 2001). This paper describes some of the methodological problems associated with the Schwartz et al. studies and outlines how these problems can be overcome in future research.

Schwartz et al.'s first experiment was funded and filmed by a major U.S. television network HBO making a documentary about the survival of bodily death. The study involved two participants (referred to as “sitters”) and five well-known mediums. The first sitter was a forty-six-year-old woman who had experienced the death of over six people in the last ten years. Schwartz et al. stated that this sitter was recommended to them by a well-known researcher in ADCs (After Death Communication) who “knew of the sitter’s case through her research involving spontaneous ADCs.” The second sitter was a fifty-four-year-old woman who had also experienced the death of at least six people in the last ten years.

During the experiment, the sitter and medium sat on either side of a large opaque screen. The medium was allowed to “conduct the reading in his or her own way, with the restriction that they could ask only questions requiring a yes or no answer.” Each sitter was asked to listen to the reading and respond to the medium’s questions by saying the word “yes” or “no” out loud. The first sitter was given a reading by all five mediums; the second sitter received readings from only two of the mediums.

A few months after the experiment, both sitters were asked to assign a number between -3 (definitely an error) to +3 (definitely correct) to each of the statements made by the mediums. The sitters placed 83 percent and 77 percent of the statements into the +3 category. Schwartz et al. also reported their attempt to discover whether “intelligent and motivated persons” could guess the type of information presented by the mediums by chance alone. The investigators selected seventy statements from the readings given to the first sitter and turned them into questions. For example, if the medium had said “your father loved dancing,” the question became “Who loved to dance?” Sixty-eight undergraduates were shown these questions, along with a photograph of the sitter, and asked to guess the answer. Schwartz et al. reported that the average number of items guessed correctly was just 36 percent, and argue that the high level of accuracy obtained by the mediums could not be due to chance guessing.

The first sitter was then invited back to the laboratory to take part in a second experiment. In this experiment she received readings from two of the mediums who also participated in the first study. Rather than being separated by an opaque screen, the sitter sat six feet behind the medium. In the first part of these two readings the sitter was instructed to remain completely silent. In the second part she was asked to answer “yes” or “no” to each of the medium’s questions. After reviewing the readings, the sitter rated 82 percent of the mediums’ statements as being “definitely correct.”

The Schwartz et al. studies suffered from severe methodological problems, namely: (1) the potential for judging bias, (2) the use of an inappropriate control group, and (3) inadequate safeguards against sensory leakage. Each of these problems will be discussed in turn.

Judging Bias

During a mediumistic reading the medium usually produces a large number of statements and the sitter has to decide whether these statements accurately describe his/her deceased friends or relatives. It is widely recognized that the sitter’s endorsement of such statements cannot be taken as evidence of mediumistic ability, as seemingly accurate readings can be created by a set of psychological stratagems collectively referred to as ”cold reading” (Hyman 1977; Rowland 1998). It is therefore vital that any investigation into the possible existence of mediumistic ability controls for the potential effect of these stratagems. Unfortunately, the Schwartz et al. study did not contain such controls, and thus it is possible that the seemingly impressive results could have been due to cold reading.

Schwartz et al. reproduced a small part of one reading in their paper, and this transcript can be used to illustrate how cold reading could account for the outcome of the studies. In the first line of the transcript the medium said, “Now, I don't know if they [the spirits] mean this by age or by generation, but they talk about the younger male that has passed. Does that make sense to you?” The sitter answered “yes.” The medium’s statement is ambiguous and open to several different interpretations. When the medium mentioned the word “younger” he/she could be talking about a young child, a young man, or even someone who died young (e.g., in their forties). The sitters may be motivated to interpret such statements in such a way as to maximize the degree of correspondence with their deceased friends and relatives if, for example, they had a strong belief in the afterlife, a need to believe that loved ones have survived bodily death, or were eager to please the mediums, investigators, and the HBO film crew.

In addition, the sitters may have endorsed the readings because some statements caused them to selectively remember certain events in their lives. As a hypothetical example, let us imagine that the medium had said, “Your son was an extrovert.” This statement may have caused the sitter to selectively recall certain life events (i.e., the times that her son went to parties and was very outgoing), forget other events (e.g., the times that he sat alone and didn't want to be with others), and thus assign a spuriously high accuracy rating to the statement.

Biased interpretation of ambiguous statements and selective remembering can lead to sitters endorsing contradictory statements during a reading. Interestingly, the short transcript reproduced by Schwartz et al. contains an example of exactly this happening:

Medium: . . . your dad speaks about the loss of child. That makes sense?

Sitter: Yes.

Medium: Twice? 'Cause your father says twice.

Sitter: Yes.

Medium: Wait a minute, now he says thrice. He’s saying three times. Does that make sense?

Sitter: That’s correct.

Some of the statements made by the mediums may also have been true of a great many people and thus had a high likelihood of being endorsed by the sitters. For example, in the transcript the medium stated that one of the spirits was a family member, and elsewhere Schwartz et al. stated that the mediums referred to “a little dog playing ball.” It is highly probable that many sitters would have endorsed both of these statements. Research has also revealed that many statements that do not appear especially general can also be true of a surprisingly large number of people. Blackmore (1994) carried out a large-scale survey in which more than 6,000 people were asked to state whether quite specific statements were true of them. More than one third of people endorsed the statement, “I have a scar on my left knee” and more than a quarter answered yes to the statement “Someone in my family is called Jack.” In short, the mediums in the Schwartz et al. study may have been accurate, in part, because they simply produced statements that would have been endorsed by many sitters.

Other factors may also increase the likelihood of the sitter endorsing the mediums’ statements. Clearly, the more deceased people known to the sitter, the greater chance they will have of being able to find a match for the medium’s comments. Both sitters knew a relatively large number of deceased people. Both of them had experienced the death of six loved ones in the last ten years, and the first sitter reported that she believed that the mediums had contacted an additional nine of her deceased friends and relatives. Thus, the sitters’ high levels of endorsement may have been due, in part, to them having a large number of deceased friends and relatives.

Control Group Biases

Schwartz et al. attempted to discover whether the seemingly high accuracy rate obtained by the mediums could have been the result of chance guesswork. However, the method developed by the investigators was inappropriate and fails to address the concerns outlined above. They selected seventy statements from the readings given to the first sitter in the first experiment and turned them into questions. For example, if the medium had said “your son is very good with his hands,” the question became “who was very good with his hands?” These questions were presented to a group of undergraduates, who were asked to guess the answers. Schwartz et al. reported that the average number of items guessed correctly was just 36 percent. However, it is extremely problematic to draw any conclusions from this result due to the huge differences in the tasks given to the mediums and control group. For example, when the medium said, “your son was very good with his hands,” the sitter has to decide whether this statement matches the information that she knew about her deceased son. However, as noted above, this matching process may be biased by several factors, including her selective remembering and the biased interpretation of ambiguous statements. For example, the sitter may think back to the times that her son built model airplanes, endorse the statement, and the medium would receive a “hit.” However, the control group were presented with a completely different task. They were presented with the question “Who was good with his hands?” and would only receive a “hit” if they guessed that the answer was the sitter’s son. They therefore had a significantly reduced likelihood of obtaining a hit than the mediums.

Conceptually, this is equivalent to testing archery skills by having someone fire an arrow, drawing a target around wherever it lands and calling it a bullseye, and then testing a “control” group of other archers by asking them to hit the same bullseye. Clearly, the control group would not perform as well as the first archer, but the difference in performance would reflect the fact that they were presented with very different tasks, rather than a difference in their archery skills.

Psychical researchers have developed various methods to overcome the problems associated with “cold reading” when investigating claims of mediumistic ability (see Schouten 1994 for an overview). Most of these methods involve the concept of “blind judging.” In a typical experiment, a small number of sitters receive a reading from a medium. The sitters are then asked to evaluate both his or her own reading (often referred to as the “target” reading) and the readings made for other sitters (referred to as “decoy” readings). If the medium is accurate then the ratings assigned to the target readings will be significantly greater than those assigned to the decoy readings. However, it is absolutely vital that the readings are judged “blind"-the sitters should be unaware of whether they are evaluating a “target” or “decoy” reading. This simple safeguard helps overcome all of the problems outlined above. Let us suppose that the medium is not in contact with the spirit world, but instead tends to use cold reading to produce seemingly accurate statements. These techniques will cause the sitters to endorse both the target and decoy readings, and thus produce no evidence for mediumistic ability. If, however, the medium is actually able to communicate with the spirits, the sitters should assign a higher rating to their “target” reading than the “decoy” readings, thus providing evidence of mediumistic ability.

It is hoped that future tests of mediumistic ability will employ the type of blind judging methods that have been developed, and frequently employed, in past tests of mediumistic ability.

However, blind judging is only one of several methodological safeguards that should be employed when testing mediumistic ability. Well-controlled tests should also obviously prevent the medium from being able to receive information about a sitter through any normal channels of communication. Unfortunately, the measures taken by Schwartz et al. to guard against various forms of potential sensory leakage appear insufficient.

Sensory Leakage

Throughout all of the readings in the first experiment, and the latter part of the readings in the second experiment, the sitter was allowed to answer “yes” or “no” to the medium’s questions. These answers would have provided the mediums with two types of information that may have helped them produce more accurate statements in the remainder of the reading. First, it is very likely that the sitter’s voice would have given away clues about her gender, age, and socioeconomic group. This information could cause the mediums to produce statements that have a greater likelihood of being endorsed by the sitter. For example, an older sitter is more likely to have experienced the death of their parents than a younger sitter, and certain life events are gender-specific (e.g., being pregnant, having a miscarriage, etc.). Second, the sitters’ answers may have also given away other useful clues to the mediums. For example, let us imagine that the medium stated, “I am getting the impression of someone male, is that correct?” If the sitter has recently lost someone very close to her, such as a father or son, then she might answer a tearful “yes.” If, however, the deceased male was an uncle that sitter didn't really know very well, then her “yes” might be far less emotional. Again, a skilled medium might be able to unconsciously use this information to produce accurate statements later in the reading. Any well-controlled test of mediumistic ability should not allow for the sitter to provide verbal feedback to the medium during the reading.

In the first part of the readings in the second experiment, the sitter was asked not to answer yes or no to any of the medium’s statements. However, the experimental set-up still employed insufficient safeguards against potential sensory leakage. The medium sat facing a video camera and the sitter sat six feet behind the medium without any form of screen separating the two of them. As such, the sitter may have emitted various types of sensory signals, such as cues from her movement, breathing, odor, etc. Parapsychologists have developed elaborate procedures for eliminating potential sensory leakage between participants (e.g., Milton and Wiseman 1997). These safeguards frequently involve placing participants in separate rooms, and often the use of specially constructed sound-attenuated cubicles. Schwartz et al. appeared to have ignored these guidelines and instead allowed the sitter to interact with the medium, and/or simply seated them behind one another in the same room. Neither of these measures represent sufficient safeguards against the potential for sensory leakage.

The investigators also failed to rule out the potential for sensory leakage between the experimenters and mediums. The second sitter in the first experiment is described as being “personally known” to two of the experimenters (Schwartz and Russek). The report also described how, during the experiment, the mediums were allowed to chat with Russek in a courtyard behind the laboratory. Research into the possible existence of mediumistic ability should not allow anyone who knows the sitter to come into contact with the medium. Schwartz allowed such contact, with their only safeguard being that the mediums and Russek were not allowed to talk about matters related to the session. However, a large body of research has shown that there are many ways in which information can be unwittingly communicated, via both verbal and nonverbal means (e.g., Rosenthal and Rubin 1978). As such, the safeguards employed by Schwartz et al. against possible sensory leakage between experimenter and mediums were insufficient.

In short, the Schwartz et al. study did not employ blind judging, employed an inappropriate control group, and had insufficient safeguards against sensory leakage. As such, it is impossible to know the degree to which their findings represent evidence for mediumistic ability. Psychical researchers have worked hard to develop robust methods for testing mediums since the 1930s (see Schouten 1994). It is hoped that future work in this area will build upon the methodological guidelines that have been developed and thus minimize the type of problems discussed here.

References

• Blackmore, S. 1994. Probability Misjudgement and belief in the paranormal: Is the theory all wrong? In D. Bierman (Ed.), Proceedings of the 37th Annual Convention of the Parapsychological Association 72-82.
• Chapman, J. 2001. Is there anybody there? Mediums perform well in scientific séance test. The Daily Mail, March 5.
• Hyman, R. 1977. Cold reading: How to convince strangers that you know all about them. Skeptical Inquirer 1(2): 18-37.
• Matthews, R. 2001. Spiritualists’ powers turn scientists into believers. The Sunday Telegraph, March 4.
• Milton, J., and R. Wiseman. 1997. Guidelines for extrasensory perception research. University of Hertfordshire Press: Hatfield, England.
• Rosenthal, R., and D.B. Rubin. 1978. Interpersonal expectancy effects: The first 345 studies. Behavioural and Brain Sciences 3, 377-386.
• Rowland, I. 1998. The Full Facts Book of Cold Reading. Ian Roland Limited: London, England.
• Schouten, S.A. 1994. An overview of quantitatively evaluated studies with mediums and psychics. The Journal of the American Society for Psychical Research, 88:221-254.
• Schwartz, G.E.R., L.G.S. Russek, L.A. Nelson, and C. Barentsen. 2001. Accuracy and replicability of anomalous after-death communication across highly skilled mediums. Journal of the Society for Psychical Research, 65(862):1-25.

For example, in 1887 Richard Hodgson and S. John Davey held seances in Britain (in which phenomena were faked by trickery) for unsuspecting sitters and requested each sitter to write a description of the seance after it had ended. Hodgson and Davey reported that sitters omitted many important events and recalled others in incorrect order. Indeed, some of the accounts were so unreliable that Hodgson later remarked: The account of a trick by a person ignorant of the method used in its production will involve a misdescription of its fundamental conditions . . . so marked that no clue is afforded the student for the actual explanation (Hodgson and Davey 1887, p. 9).

In a partial replication of this work, Theodore Besterman (1932) in Britain had sitters attend a fake seance and then answer questions relating to various phenomena that had occurred. Besterman reported that sitters had a tendency to underestimate the number of persons present in the seance room, to fail to report major disturbances that took place (e.g., the movement of the experimenter from the seance room), to fail to recall the conditions under which given phenomena took place, and to experience the illusory movements of objects.

More recently, Singer and Benassi in the United States (1980) had a stage magician perform fake psychic phenomena before two groups of university students. Students in one group were told that they were about to see a magician; the other group, that they were about to witness a demonstration of genuine psychic ability. Afterward, all of the students were asked to note whether they believed the performer was a genuine psychic or a magician. Approximately two-thirds of both groups stated they believed the performer to be a genuine psychic. In a follow-up experiment the researchers added a third condition, wherein the experimenter stressed that the performer was definitely a magician. Fifty-eight percent of the people in this group still stated they believed the performer to be a genuine psychic!

These studies admirably demonstrate that eyewitness testimony of supposedly paranormal events can be unreliable. Additional studies have now started to examine some of the factors that might cause such inaccuracy.

Clearly, many supposedly paranormal events are difficult to observe simply because of their duration, frequency, and the conditions under which they occur. For example, ostensible poltergeist activity, seance phenomena, and UFO sightings often occur without warning, are over within a few moments, take place under poor lighting or weather conditions, or happen at a considerable distance from observers. In addition, some people have sight/hearing deficiencies, while others have observed these phenomena under the influence of alcohol, drugs, or when they are tired (especially if they have had to wait a relatively long time for the phenomena to occur).

It is also possible that observers’ beliefs and expectations play an important role in the production of inaccurate testimony. Different people clearly have different beliefs and expectations prior to observing a supposed psychic — skeptics might expect to see some kind of trickery; believers may expect a display of genuine psi. Some seventy years ago Eric Dingwall in Britain (1921) speculated that such expectations may distort eyewitness testimony:

The frame of mind in which a person goes to see magic and to a medium cannot be compared. In one case he goes either purely for amusement or possibly with the idea of discovering ‘how it was done,’ whilst in the other he usually goes with the thought that it is possible that he will come into direct contact with the other world (p. 211).

Recent experimental evidence suggests that Dingwall’s speculations are correct.

Wiseman and Morris (1995a) in Britain carried out two studies investigating the effect that belief in the paranormal has on the observation of conjuring tricks. Individuals taking part in the experiment were first asked several questions concerning their belief in the paranormal. On the basis of their answers they were classified as either believers (labeled “sheep”) or skeptics (labeled goats”). [Gertrude Schmeidler, City College, New York City, coined the terms sheep and goats.]

In both experiments individuals were first shown a film containing fake psychic demonstrations. In the first demonstration the “psychic” apparently bent a key by concentrating on it; in the second demonstration he supposedly bent a spoon simply by rubbing it.

After they watched the film, witnesses were asked to rate the “paranormal” content of the demonstrations and complete a set of recall questions. Wiseman and Morris wanted to discover if, as Hodgson and Dingwall had suggested, sheep really did tend to misremember those parts of the demonstrations that were central to solving the tricks. For this reason, half of the questions concerned the methods used to fake the phenomena. For example, the psychic faked the key-bending demonstration by secretly switching the straight key for a pre-bent duplicate by passing the straight key from one hand to the other. During the switch the straight key could not be seen. This was clearly central to the trick’s method; and one of the “important” questions asked was whether the straight key had always remained in sight. A second set of “unimportant” questions asked about parts of the demonstration that were not related to the tricks’ methods.

Overall, the results suggested that sheep rated the demonstrations as more “paranormal” than goats did, and that goats did indeed recall significantly more “important” information than sheep. There was no such difference for the recall of the “unimportant” information.

This is not the only study to investigate sheep/goat differences in observation and recall of “paranormal” phenomena. Jones and Russell in the United States (1980) asked individuals to observe a staged demonstration of extrasensory perception (ESP). In one condition the demonstration was successful (i.e., ESP appeared to occur) while in the other it was not. All individuals were then asked to recall the demonstration. Sheep who saw the unsuccessful demonstration distorted their memories of it and often stated that ESP had occurred. Goats tended to correctly recall the demonstration, even if it appeared to support the existence of ESP.

In addition, Matthew Smith in Britain (1993) investigated the effect that instructions (given prior to watching a film containing a demonstration of apparent psychic ability) had on the recall of the film. Individuals were split into two groups. One group was told that the film contained trickery; the other group was told that it contained genuine paranormal phenomena. The former group recalled significantly more information about the film than the latter group.

All of the above experiments were carried out in controlled laboratory settings. However, another recent study suggests that the same inaccuracies may exist in a more natural setting, namely, the seance room.

Many individuals have reported experiencing extraordinary phenomena during dark-room seances. Eyewitnesses claim that objects have mysteriously moved, strange sounds have been produced, or ghostly forms have appeared, and that these phenomena have occurred under conditions that render normal explanations practically impossible.

Believers argue that conditions commonly associated with a seance (such as darkness, anticipation, and fear) may act as a catalyst to produce these phenomena (Batcheldor 1966). Skeptics suggest that reports of seances are unreliable and that eyewitnesses are either fooling themselves or being fooled by fraudulent mediums.

The authors carried out an experiment in the United Kingdom to assess both the reliability of testimony relating to seance phenomena, and whether paranormal events could be produced in a modern seance. We carried out our experiment, titled “Manifestations,” three times. Twenty-five people attended on each occasion. They were first asked to complete a short questionnaire, noting their age, gender, and whether they believed that genuine paranormal phenomena might sometimes take place during seances.

A seance room had been prepared. All of the windows and doors in the room had been sealed and blacked out, and twenty-five chairs had been arranged in a large circle. Three objects — a book, a slate, and a bell — had been treated with luminous paint and placed onto three of the chairs. A small table, the edges of which were also luminous, was situated in the middle of the circle. Two luminous maracas rested on the table.

Following a brief talk on the aims of the project, the participants were led into the darkened seance room. Richard Wiseman played the part of the medium. With the help of a torch, he showed each person to a chair, and, where appropriate, asked them to pick up the book, slate, or bell.

Next, he drew participants’ attention to the table and maracas. Those participants who had picked up the other luminous objects were asked to make themselves known, and the “medium” collected the objects one by one and placed them on the table.

He then pointed out the presence of a small luminous ball, approximately 5 centimeters in diameter, suspended on a piece of rope from the ceiling. Finally, he took his place in the circle, extinguished the torch, and asked everybody to join hands.

The medium first asked the participants to concentrate on trying to move the luminous ball and then to try the same with the objects on the table. Finally, the participants were asked to concentrate on moving the table itself. The seance lasted approximately ten minutes.

Clearly, it was important that some phenomena occurred to assess the reliability of eyewitness testimony. The maracas were therefore “gimmicked” to ensure their movement during the seance. In the third seance the table was also similarly moved by trickery. Finally, we also used trickery to create a few strange noises at the end of each seance.

All of the ungimmicked objects were carefully placed on markers so that any movement would have been detectable. After leaving the seance room, the participants completed a short questionnaire that asked them about their experience of the seance.

No genuine paranormal phenomena took place during any of the seances. However, our questionnaire allowed us to assess the reliability of participants’ eyewitness testimony.

Would participants remember which objects had been handled before the start of the seance? As the maracas were gimmicked, we had to ensure that they were not examined or handled by anyone. Nevertheless, one in five participants stated that they had been. This was an important inaccuracy, as observers are likely to judge the movement of an object more impressive if they think that the item has been scrutinized beforehand.

This type of misconception was not confined to the maracas. In the first two seances, the slate, bell, book, and table remained stationary. Despite this, 27 percent of participants reported movement of at least one of these. In the third seance the table was gimmicked so that it shifted four inches toward the medium, but participants’ testimony was again unreliable, with one in four people reporting no movement at all.

An interesting pattern develops if the results are analyzed by separating the participants by belief. The ball, suspended from the ceiling, did not move at any time. Seventy-six percent of disbelievers were certain that it hadn’t moved. In contrast, the same certainty among believers was only 54 percent. In addition, 40 percent of believers thought that at least one other object had moved, compared to only 14 percent of disbelievers. The answers to the question “Do you believe you have witnessed any genuine paranormal phenomena?” perhaps provide the most conclusive result for the believer/ disbeliever divide. One in five believers stated that he or she had seen genuine phenomena. None of the disbelievers thought so. This would suggest that while we are all vulnerable to trickery, a belief or expectation of paranormal phenomena during seances may add to that vulnerability.

The results clearly show that it is difficult to obtain reliable testimony about the seance. Indeed, our study probably underestimated the extent of this unreliability as the seance lasted only ten minutes and participants were asked to remember what had happened immediately afterward.

Although a minority of participants believed that they had observed genuine paranormal phenomena, it does not seem unreasonable to assume that these individuals might be the most likely to tell others about their experience. Our results suggest that many of their reports would be fraught with inaccuracies and it might only take a few of the more distorted accounts to circulate before news that “genuine” paranormal phenomena had occurred became widespread.

In short, there is now considerable evidence to suggest that individuals’ beliefs and expectations can, on occasion, lead them to be unreliable witnesses of supposedly paranormal phenomena. It is vital that investigators of the paranormal take this factor into account when faced with individuals claiming to have seen extraordinary events. It should be remembered, however, that such factors may hinder accurate testimony regardless of whether that testimony is for or against the existence of paranormal phenomena; the observations and memory of individuals with a strong need to disbelieve in the paranormal may be as biased as extreme believers. In short, the central message is that investigators need to be able to carefully assess testimony, regardless of whether it reinforces or opposes their own beliefs concerning the paranormal.

Accurate assessment of the reliability of testimony requires a thorough understanding of the main factors that cause unreliable observation and remembering. Research is starting to reveal more about these factors and the situations under which they do, and do not, occur. Indeed, this represents part of a general movement to increase the quality of the methods used to investigate psychic phenomena (Wiseman and Morris 1995b). Given the important role that eyewitness testimony plays in parapsychology, understanding observation is clearly a priority for future research.

References

• Batcheldor, K. J. 1966. Report on a case of table levitation and associated phenomena. Journal of the Society for Psychical Research, 43: 339-356.
• Besterman, T. 1932. The psychology of testimony in relation to paraphysical phenomena: Report of an experiment. Proceedings of the Society for Psychical Research, 40: 363-387.
• Dingwall, E. 1921. Magic and mediumship. Psychic Science Quarterly, 1(3): 206-219.
• Hodgson, R., and S. J. Davy. 1887. The possibilities of mal-observation and lapse of memory from a practical point of view. Proceedings of the Society for Psychical Research, 4:381-495.
• Jones, W. H. and D. Russell. 1980. The selective processing of belief disconfirming information. European Journal of Social Psychology, 10:309-312.
• Smith, M. D. 1993. The effect of belief in the paranormal and prior set upon the observation of a ‘psychic’ demonstration. European Journal of Parapsychology, 9:24-34.
• Singer, B. and V. A. Benassi. 1980. Fooling some of the people all of the time. SKEPTICAL INQUIRER, Winter: 17-24.
• Wiseman, R. J. and R. L. Morris. 1995a. Recalling pseudo-psychic demonstrations. British Journal of Psychology, 86:113-125.
• —. 1995b. Guidelines for Testing Psychic Claimants. Buffalo, N.Y.: Prometheus Books.