The hot, still night was illuminated by a full moon. The two shadowy figures moving along the empty road wondered if this would interfere with their mission.

“Are you sure you took everything?” asked the slender one.

“Of course!” said the shorter one, who was carrying a backpack. “I checked the inventory. I even took the infrared goggles and a telescopic steel rod.”

“Really?”

“Well . . . as a form of self-defense. You never know.”

The two reached a tall, black gate.

“It’s locked.”

“Hold this,” said the shorter one, handing the backpack to his colleague. After searching it, he took out a large ring with a dozen keys attached.

“Here they are! They assured me that with these there would be no problems.”

“We’ll see. . . .”

One at a time, the short fellow inserted the keys in the keyhole. But not one worked.

“Damn! I knew it. We should have checked first that it worked.”

The road was empty. Only one car had passed since Slender and Shorty stopped by the gate, but it did not slow down. The dark shadows hid them from the light.

“All right, if that’s the way it has to be. . . .”

Slender shined a pocket light into the keyhole. “It’s an old Wally model, there should be no problem.”

Shorty took a leather case out of his pocket and opened it. There were a dozen different lockpicks. One was chosen, and the operation started. “It should be no problem,” puffed Shorty, who was crouched on his legs while trying to pick the lock, sweat dripping from his face. “Yeah, it’s easy when you just hold the light and someone else has to do the dirty job.”

“Cut the chatter. Let’s move along.”

After a few more attempts there was a reassuring “click.” The door was open.

“Quick!” snapped Slender. “Stand up.”

“What . . . ?”

“I said quick, get inside!” Slender pushed his mate in the dark hallway and closed the gate. “Don’t say a word.”

They both hid behind a wall, holding their breath. A police car passed by without stopping.

“That was close!” sighed Slender.

Shorty protested. “Close for what? You make it seem like we are two burglars here!”

Slender smiled. “Yeah, and it’s more fun, isn’t it?”

“We are here on a scientific mission,” continued Shorty. “We are not on a secret hunt to rob lost treasures or something like that.”

Slender turned on his pocket light and did not reply. They were in a dark corridor, but down the hall a door that led to the field outside could clearly be seen. It was open when they reached it.

When they stepped outside, the pocket light was no longer needed. The moon was quite bright, but the field, full of a thousand flickering flames, was more luminous. Quite an unexpected view—surreal but almost romantic. Slender regretted he was there with Shorty and not with his girlfriend.

However, it was indisputable: a cemetery at midnight was a sight not to be missed.

Luminous Fungis and
Earth Lights

The two mysterious figures in the story above are my friend and colleague Luigi Garlaschelli and myself. Actually, Luigi is not that short, but I needed an easy descriptor for him. And since he is just a little shorter than I am . . . my apologies, Gigi!

The night visits at the Major Cemetery in Pavia, Italy, took place some time ago when we decided it was time to investigate the “will o’ the wisp” phenomenon. Of course, we obtained official permission from the county administration—“scientific purposes” was the reason we gave for our requested visit. We were quite fascinated by this rare luminous phenomenon, a source of all kinds of supernatural tales.

Also known as ignis fatuus, Latin for temporary fire, will o’ the wisps are in fact said to be ghostly lights, usually seen around graveyards and marshes at night. They look like faint flames or a flickering, glowing fog, usually green, that sometimes appears to recede if approached. Folklorists have collected all kinds of legends related to these mysterious lights, including the fact that they could be some form of spirit lights or have a paranormal origin. Science, however, has precious few facts to offer.

Some have proposed that Armillaria, a parasitic kind of fungi known also as “honey fungus,” could be responsible for some of the apparitions. Some species of Armillaria are bioluminescent and may have been mistaken for will o’ the wisps.

According to another theory, the wisps are nothing more than barn owls with luminescent plumage. Hence, the possibility of them floating around reacting to other lights could explain their strange behavior.

In the 1970s, John Derr and Michael Persinger of the Laurentian University in Sudbury, Ontario, Canada, put forth a theory that these lights may be generated piezoelectrically under a tectonic strain.

The theory suggests that the strains that move faults also cause heat in the rocks, vaporizing the water in them. Rocks and soils containing piezoelectric elements such as quartz (or silicon) may also produce electricity, which is channeled up through soils via a column of vaporized water until it reaches the surface, somehow displaying itself in the form of earth lights. If correct, this could explain why such lights can behave in an electrical and erratic—or even apparently intelligent—manner.

Persinger thinks that his theory can be used to predict the manifestation of earthquakes and, along the way, explain many UFO sightings. “When the specific equations between UFO reports (the contemporary label for luminous events) and earthquakes in the central U.S.A. between 1950 and 1980 were applied to the 19th century (earthquakes were recorded then), there were predictable peaks in the numbers of luminous events for specific years,” says Persinger.

“Although there were no reports of ‘UFOs’ in the historical newspapers, there were reports of ‘odd air ships’ and ‘phantom balloons.’ The massive ‘flap’ of 1897, through several tens of states in the southeastern U.S.A., was followed by one of the largest earthquakes in the region.”

As interesting as this theory sounds, and as interesting as it would be to discover whether UFO “flaps” of the past century have been followed by major earthquakes or not, we wanted to test a different kind of will o’ the wisp. The kind that is said to appear in the presence of freshly buried bodies.

Decaying Bodies

One of the most popular scientific explanations for ghost lights is that the oxidation of hydrogen phosphide and methane gas produced by the decay of organic material may cause glowing lights to appear in the air. And this phenomenon is said to occur more easily in the proximity of “fresh” burials.

Thus, we positioned ourselves, with video cameras rolling, in an area of the cemetery where burials had taken place that same day and a few days before. The idea was to document on film the formation of a will o’ the wisp.

Luigi had even built an aspiring pump that would allow him to “suck” the wisp inside a hermetically sealed container in order to later test its chemical composition in the lab. In fact, Luigi has now been able to replicate the lights in his laboratory at the Department of Chemistry in Pavia with the help of his colleague Paolo Boschetti.

At first, the idea was to test the “cool fire” effect. Luigi explains it this way: “According to one hypothesis, the will o’ the wisp is a sort of cold flame, inconsistent with a normal combustion of methane, as reliable eyewitnesses have reported. ‘Cool flames’ can indeed be generated if vapors of suitable organic compounds (such as ethyl ether) come in contact with a hot surface kept at temperatures around 200–300°C [392–572ºF]. These luminescent pre-combustion haloes are sufficiently cool that a hand or a piece of paper can be put in them without being burned.”

The main objection to this interesting hypothesis is that the necessary vapors are not known components of marsh gases, and the presence of surfaces at such high temperatures is difficult to find in nature.

“It is often stated that the phenomenon originates from the spontaneous combustion of gases generated underground by anaerobic fermentation processes,” continues Luigi. “These gases consist mainly of methane and carbon dioxide. Small amounts of phosphine (PH3) and diphosphine (P2H4) [self-igniting on contact with the air] would act as a ‘chemical match’ for the combustible methane.

“Although this hypothesis is one century old, the presence of PH3 in marsh gases has only recently been demonstrated. If the will o’ the wisp indeed is a hot flame, this conjecture might be correct.” If, on the contrary, a will o’ the wisp is a cool “flame,” then the cold chemiluminescence of some compound naturally occurring in marsh gases appears to be a more appealing explanation.

Luigi reconsidered a century-old experiment conducted by German chemists in which phosphine, oxygen, and an inert gas were fed through three small nozzles at the base of a vertical glass tube. By carefully adjusting the flow of the inlets, a faint flickering luminescence could be seen in the dark near the top of the tube due to the chemiluminescence of phosphine.

Luigi built the necessary equipment with a 500 mL flat-bottomed flask, in which he put some solid phosphorous acid. The flask was stoppered by a silicone septum through which a mixture of air and nitrogen was stored on water within a gas tank and fed by a needle. A second needle in the septum provided for the necessary outlet. The flask was flushed with nitrogen and put on a hot plate that was heated to 200°C (392ºF).

“It works!” shouted Luigi, probably feeling a little like Dr. Frankenstein.

The decomposition of phosphorous acid generated phosphine, and a fog formed in the flask. When the air and nitrogen stream was fed into the phosphine vapors, a faint, pale-greenish light was clearly visible in the darkness.

The success in the lab, however, was not matched by success in the field. We spent the entire night at the cemetery, but nothing happened except buzzing and biting mosquitoes. After that there have been repeated visits to cemeteries, graveyards, marshes, and the like, and Luigi has started to carry with him a very sensitive phosphine detector—a portable Draeger Xam-7000—but so far with no luck.

Being able to reproduce spooklights in a lab is one thing. But to see it up close with your own eyes in a cemetery at night is quite another. Hopes are still high, however. There never is a shortage of fresh burials, and hunting season for will o’ the wisps is always open.

A conference on “anomalous cognition” features unusual claims and raises issues on the role of scientific evidence, replicability, and philosophy of science, plus another: when should one stop looking for evidence in support of an elusive effect?

AMIR RAZ

Amir Raz holds the Canada Research Chair in the Cognitive Neuroscience of Attention at McGill University and the SMBD Jewish General Hospital, where he heads the Cognitive Neuroscience Laboratory and the Clinical Neuroscience and Applied Cognition Laboratory, respectively.

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“What exactly is anomalous cognition?” As a cognitive scientist, I wondered about this question as I was peering over an intriguing invitation to attend an exclusive Meeting of Minds (MoM) conference on this very topic.¹ I had been counting the days before the MoM, until finally in July 2007 about sixty researchers got together at the University of British Columbia in Vancouver, Canada. To avoid media coverage, the organizers targeted a select group of speakers, and attendance was by invitation only. I was surprised when the conference turned out to be a series of presentations, including reports of what are arguably the best accounts in favor of the possibility of things such as parapsychology and psychic influence, also known as psi. The meeting brought together behavioral scientists and experimental psychologists—most of the audience for the talks—a few skeptics, and a group of self-labeled psi researchers, most of the presenters. As a special treat, a handful of renowned panelists—two Nobel laureates and two distinguished professors of psychology—offered pithy summaries of their impressions following the presentations. It did not take long to realize that anomalous cognition is a new euphemism for the time-honored claims of psi, including extrasensory perception (ESP) and telekinesis.

Initially, I was not sure whether I was invited as a scientist, a skeptic, a magician, or as a friend of one of the organizers. Although I am not a parapsychologist, I am genuinely interested in what I refer to as atypical cognition and rarely shy away from investigating areas within my purview, even those considered as fringe by most of my colleagues. For example, I have been studying the brain computations that occur during planes of altered consciousness, including the cognitive neuroscience of phenomena such as sleep-deprivation, hypnosis, and meditation. At the same time, I consider myself a skeptic—of the deferentially inquisitive rather than gravely unyielding variety—who thrives on converging independent replications of rigorous empirical evidence, not on doctrinaire viewpoints. Finally, it was nice to see among the MoM guests a few fellow conjurors who are, foremost, scientists. Their presence was reassuring, if only to avoid thinking about my answer to the phrase “Are you the best magician among scientists or the best scientist among magicians?” which I have heard one too many times. In that crowd, I was neither.

Having spoken to one of the organizers a few weeks before the meeting, it was my understanding that the conference’s leadership envisaged it as an opportunity to present some of the most compelling data sets in support of anomalous cognition and to urge “mainstream” scientists to foster sufficient open-mindedness to consider a more programmatic investigation into these fields based on these findings. That approach seemed fair and appropriate. Although it was unclear to me at that time what exactly anomalous cognition is, I thought then—as I do now—that it is certainly legitimate to advocate for the possibility of anomalous cognition, including psi. The agenda at the meeting, however, went beyond asking that “mainstream” scientists consider the possibility of psi: it intimated that scientific evidence for psi was solid and replicable. Furthermore, it went on to propose that a major goal of the MoM was to consider why scientific and lay communities do not appreciate the existence of psi.

Interestingly, a number of presenters who argued for the possibility of psi were mainstream researchers, at least in the sense that they had trained and worked in some of the world’s most prestigious institutions of higher learning. While several speakers judiciously implied the possibility of psi, a few explicitly claimed that, based on rigorous data, several anomalous phenomena were veridical. It is perilous, however, to overlook the tenuous boundary between suggesting the possibility of certain phenomena and insinuating—not to mention explicitly submitting—that such anomalies actually exist. During the MoM several speakers blurred this boundary, some in letter and some in spirit, and a few unflinchingly crossed it.

As the conference unfolded, serious issues began to surface concerning the role of scientific evidence, replicability of findings, and philosophy of science. In addition, another question gradually emerged, one that scientists seldom ponder: when is it rational to end the pursuit of a hard-to-pin-down goal? In other words, when should one stop looking for evidence in support of an elusive effect?

As a matter of good practice, members of the scientific community tend to be skeptical. Science thrives on a skeptical approach, and scientists are typically conservative in what they consider a “generally accepted view.” Two types of errors, however, stand in the way of any gatekeeper of science. One pertains to how nonexistent phenomena may pass as real or generally accepted; the other pertains to how real phenomena, which should be generally accepted, may pass as nonexistent. Scientists typically pay more attention to the former trap, and some consequently tend to be overzealous or dogmatically skeptical; members of this staunch group can be skeptical of their own belly buttons. The second trap, however, is usually less explored. If psi effects are real, then the scientific establishment needs to be careful not to deny a phenomenon that may later become a generally accepted view.

Carl Sagan popularized Marcelo Truzzi’s dictum that extraordinary claims require extraordinary proof. Although Truzzi used the word “evidence” rather than Sagan’s “proof,” the former, too, had paraphrased earlier statements by great skeptics such as David Hume and Pierre-Simon Laplace. Most scientists still uphold the “extraordinary” motto; however, many of them might not realize that later in his life Truzzi recanted his own maxim. While we can speculate why he did, it remains unclear what constitutes an extraordinary claim. Does claiming to possess X-ray vision or that the sun will not shine tomorrow count as extraordinary? Deciding on what constitutes an extraordinary claim is probably related to our working knowledge—the proverbial a priori Bayesian probabilities with which we navigate the world. We typically use the inductive process to decide whether claims are extraordinary. It would be easier to accept X-ray vision, for example, if we suddenly discovered special receptors for that wavelength in the human body. The presence of such receptors is unlikely—if only because they have eluded us heretofore—but not impossible. That the sun will not shine tomorrow is perhaps a more extraordinary claim because our inductive experience, not to mention our knowledge of physics, suggests otherwise. In addition, while it may be difficult to agree on what would lend extraordinary support to a claim, scientists usually agree on what constitutes unimpressive evidence. Thus, for example, experimental results that do not replicate, effects that are very small and tenuous, flaws of design and methodology, insufficient sample size, inadequate statistical analyses, and lack of a theoretical basis may all contribute to weak evidence.

Conducting parapsychology experiments is an unprotected legal act: anyone can do it without a special license. At the conference, a few talks featured nonpsychologists, including physicists, engineers, and other professionals with little or no training in behavioral science, who nonetheless reported data from studies they conducted in experimental psychology. While at least some of these studies were markedly inadequate and contained glaring shortcomings, others consisted of more careful efforts, sometimes with intriguing results. Physicists with little training in behavioral science, however, are probably not the best professionals to conduct complex psychological experiments in the same way that experimental psychologists with little background in theoretical physics are likely suboptimal candidates to carry out empirical research in quantum mechanics. Of course, individuals who combine psychology with relevant interdisciplinary knowledge, including that from the exact, life, social, and engineering sciences, may have relative merits. In this regard, magicians—those performers who are well-versed in the art of human deception and trickery—may have especially good insights to offer. Whereas I have been an active magician and spent considerable time following claims of the paranormal, I am now a professional academic scientist, at least in the sense that a reputable university supports my research and salary. These credentials make me neither omniscient nor an authority on truth. But they do suggest at least some experience with and perhaps proficiency in assessing psi claims.

Science provides an evanescent form of truth. We never get there, but we can judge how close we are. One test that we can perform requires the convergence of evidence over multiple researchers, methods, labs, and periods. We should probably apply the same time-honored, scientific principle to the study of psi. The psi phenomena reported in the conference, however, tended to comprise very small, elusive effects that were difficult to replicate. In the few cases seemingly supported by replication or meta-analysis (a statistical method that can provide a more complete picture than individual small studies can), multiple caveats cast long shadows over the raw data and the inclusion/exclusion criteria of specific studies. Statistical analysis, however rigorous, is independent of the quality of the unprocessed information: it crunches both meaningful and less meaningful data indiscriminately. Thus, independent of the statistical methods, interpretation of the results is inconclusive at best.

It became clear that proponents of the existence of psi, who typically claim that evidence for psi is bona fide and replicable, largely base their claims on the results of several meta-analyses. It is precarious, however, to rely almost exclusively on the outcomes of meta-analyses for support. Meta-analytical studies are retrospective, not prospective, and confound exploratory with confirmatory investigation. In addition, in the known cases where more than one team of investigators have conducted a meta-analysis of the same research domain within psi, the conclusions have been strikingly different (e.g., a psi proponent reported a meta-analysis of Ganzfeld studies with an average effect size that significantly differed from zero with odds of more than a trillion to one while another meta-analysis of the Ganzfeld data concluded that the average effect size was consistent with zero). This lack of robustness is difficult to reconcile.

Scientists, including the better and smarter of them, are fallible beings prone to the entire spectrum of human behaviors and blunders. People, including scientists, often ask unscientific questions: do you believe that hypnosis can reduce pain? Do you suppose that Prozac can help depression? Pristine scientists, however, do not believe or suppose. Instead, they look at the data and ask whether the evidence supports the hypothesis. At least in theory, researchers’ beliefs should be immaterial to the results of their experiments, because science is about empirical evidence. In reality, however, the experimenter’s beliefs may introduce a substantive bias to the interpretation of data and sometimes even to more nuanced aspects. For example, beliefs and attitudes may bias participant recruitment and influence their expectations, affect feedback, and may even subtly permeate data collection and analysis. At the MoM, it quickly became evident that people had strong beliefs. “What kind of data would make you change your mind?” I asked many a colleague. While several associates danced around the answer with grace and elegance, most coy responses amounted to one troublesome sentiment: “none.”

In a short, informal gathering following the main MoM event, a few participants suggested that perhaps psi effects are not amenable to standard scientific scrutiny because the alleged effects, when they do occur, typically disappear soon after the initial experiment, thereby preventing replication. This “decline effect”—the tendency of psi phenomena to wane over time, sometimes reaching chance levels—is most peculiar. Another commonly reported outcome is the “experimenter effect”: a difference in participants’ performance as a function of the individual who is administering the experiment. It may be interesting to further pursue the latter, as it may also elucidate the therapeutic alliance we so desperately seek with our health practitioners. Nonetheless, we should heed Karl Popper, an influential twentieth-century philosopher of science, who taught us that a proposition or theory is scientific if it permits the possibility of being shown false—the falsifiability criterion. The history of science shows that many theories were not initially falsifiable not because they were not sufficiently well-operationalized in terms of measurable variables—as was the case in Freudian theories, for example—but because they were not fully developed. Such theories, however, have often served a valuable purpose. Proponents of psi may feel that they operate in a similar climate: they might not yet be ready for “prime time” but may want to use the controversy surrounding psi to generate interest and perhaps even a large body of research from which new theories and empirical findings can evolve.

Theory is important, and the life of the scientific theoretician is anything but easy because experiments are inexorable evaluators of one’s work. These unfriendly judges—the experiments—never say yes to a theory and in the great majority of cases assert a flat-out no. Even in the most favorable of situations, they suggest only a “perhaps.” Historically, rather than anchor their observations in a theoretical framework, most proponents of psi have focused on a technicality: their pivotal criterion for the presence of psi hinged on obtaining a statistically significant departure from chance. It became gradually evident, however, that in this way it was difficult to specify what properties typified psi and what criteria determined its absence. Nowadays, theories of psi abound, with most loosely brushing against quantum theory and generating no specific, testable, and falsifiable predictions. Such theories, some rather grandiose, appear especially disjointed, as they are not grounded in supporting experimental data.

“A wise man…proportions his belief to the evidence,” wrote Hume in his 1748 essay Of Miracles. Having attended all the talks at the meeting, the collective evidence that I have examined does not support the hypothesis that psi phenomena exist. Neither I nor anyone else, however, can reject this hypothesis and conclude that such phenomena do not exist. For example, based on insufficient evidence we cannot decisively conclude that the Tooth Fairy does not exist. But the burden of “proof” rests with those who make the extraordinary claim. On the one hand, when intriguing nascent evidence presents itself, further investigation should ensue. On the other hand, skeptics will probably continue to maintain that psi is unlikely, and proponents will almost certainly continue to look for new ways to demonstrate their claims.

The air was effervescent as each panelist offered an extemporaneous eight-minute summary. Peppering their comments with humor and panache, the psychologists were largely unimpressed by the evidence and pointed to a number of the abovementioned weaknesses. The Nobel laureates, however—one in physics and one in chemistry—echoed a favorable and more accepting tenor. One mentioned atmospheric science as a metaphor for the science of psi, suggesting that psi phenomena may be difficult to predict and replicate consistently in the same way that weather forecasts are nebulous. The other described his experiences with personal acquaintances whom he considered to be genuine psychics.

These last statements left me rubbing my ears in disbelief. On the one hand, albeit far from perfect, weather forecasts have gotten better over the past few decades and are certainly more reliable than outcome predictions from psi research. On the other hand, befriending individuals who claim psychic abilities is hardly firm grounds for scientific exchange.

Individuals, including intelligent persons, are infamously irrational, and one personal “psi experience” is often more compelling than multiple converging scientific accounts. Social psychologists have coined this phenomenon the “vividness” effect. Being a scientist, a prestidigitator, and a skeptic who is keenly aware of his bellybutton, I’d be curious to see compelling scientific demonstrations of psi (i.e., a string of multiple successful experiments by several independent investigators producing lawful and replicable outcomes). Alas, I have found none to date. But when do you conclude that the effect you are seeking is unlikely? When do you stop looking?

Data in support of psi have so far failed to meet the acceptable scientific standards of lawfulness, replicability, objectivity, falsifiability, and theoretical coherence. A group of dogmatically skeptical individuals seems to consistently reject psi research because of granitic prejudices, but navel-denying skepticism is incongruent with good science. While some scientists may indeed reject psi out of prejudice, they typically do not “discriminate” against psi; they show a similar “prejudice” against any claim that seemingly violates fundamental principles of current scientific theory. A healthy first reaction to any departure from existing frameworks is to look for defects in the supporting evidence. If such defects are not apparent, it is time to insist on obtaining independent replications. Until such evidence is forthcoming, it would be difficult for the scientific community to accept a claim for an anomaly.

Highly biased perceptions of reality may be at odds with the findings of science, and establishing the existence of paranormal phenomena might well comprise an intractable task. If compelling evidence were to materialize, however, scientists should be willing to change their minds. Members of the scientific community should be amenable, at least in some measure, to the possibility of novel phenomena. At the same time, proponents of new claims should provide compelling “proof,” and everyone should be sufficiently critical to dismiss claims that already have been found specious. While some of us may have concluded that the Tooth Fairy seems unlikely, others may keep on looking for her…. Still others may be undecided.