teven Spielberg's latest film, Minority Report (based on the Philip K. Dick story of the same name) features a trio of genetically modified "pre-cogs" who are capable of glimpsing future events—specifically, murders. The USA Network's new series, The Dead Zone (based on the Stephen King novel), concerns a schoolteacher, Johnny Smith, whose traumatic injury has awakened a new part of his brain—one which is not only precognitive but also clairvoyant—able to see past and present events in distant locations. Including murders and geopolitical disasters. And countless other science-fiction stories, from Starship Troopers to X-Men, have dealt with the related concepts of telepathy (mind reading) and telekinesis (mind over matter).
These concepts make for excellent fiction, partly because the anecdotal evidence for extrasensory perception (ESP, also known as psychic ability, psionics or psi) has always been strong. Studies show that about 50 percent of Americans believe in it—roughly the same percentage who believe in an afterlife or in the safety of genetically modified foods. Demographically speaking, belief in ESP is most strongly held by Catholic Hispanic women (around 65 percent), but I find it interesting and suggestive that the lowest rates of belief (less than 35 percent) occur among the group most responsible for testing the matter scientifically: experimental psychologists.
Because it deals with the mysteries and unpredictabilities of the human mind, psychology is often referred to as a soft science, in contrast with "hard" subjects like chemistry or physics, whose principles are rigorous and deterministic. Still, human behavior is not infinitely variable, and with their intensive statistical training, psychologists know the difference between signal and noise. They are routinely able to identify tendencies in human behavior, through experiments which other psychologists can easily and consistently reproduce. In this sense, psychology is very much like other fields of medicine, which generally deal in probabilities rather than certainties.
Unfortunately, experiments in psychic phenomena do not share this trait. Most of them show no evidence for psi of any kind, and for the rare studies which cross the threshold of statistical significance, replication has been difficult or impossible. One obvious conclusion to draw from this is that psi does not exist, and the handful of positive results are merely statistical flukes. However, the counterargument given by the field's faithful is also reasonable: that psychic ability—like other savant talents—is concentrated in a small percentage of the total human population, whereas most studies of psychic phenomena deal with random volunteers from a college campus.
The mind is a powerful thing to taste
So what's the truth? I'll start by saying there is more to the world (and the universe, and the human mind) than we are presently aware of, and I really would like to discover that ESP exists. It's such a romantic notion, and very much in keeping with our human self-image. Unfortunately, the supporting evidence is murky at best.
If we assume that any real phenomenon has an explanation in the physical world, then telekinesis is surely the most difficult psychic ability to explain. What force is responsible for lifting and manipulating the target objects? And indeed, no human being has ever demonstrated the mental ability to swing or rotate a pendulum suspended in a trick-proof evacuated container. Other studies, which focus on the paranormal biasing of random physical events such as dice rolls, haven't met with much greater success.
As for precognition, if there were such a thing, its explanation would probably involve quantum mechanics, which has shown a mysterious connection between distant particles which seems to transcend the boundaries of time and space (see "Faster Than Light Part II: The Quantum Connection"). And while there is no conclusive evidence for precognition, there are a few suggestive studies, such as Princeton University's Global Consciousness Project, which hypothesizes that the collective human awareness (what Christian philosopher Tielhard de Chardin called the "noosphere") can affect the output of a network of random-number generators scattered throughout the world.
It sounds kooky, but in fact their published results—available on the Web at noosphere.princeton.edu—claim a slight but statistically significant correlation between anomalous (i.e., non-random) output from the generators, and the occurrence of global/geopolitical events which focus the attention of millions or billions of people. In some cases—including the ultimate example on 9/11/2001—these statistical blips slightly precede the events themselves, lending some credence to a precognitive ability, either for the human population or for the number-generating machines themselves.
Of course, the pattern-matching hardware of the human brain is powerful enough to pull "meaning" even from the static on a TV screen, which can appear as an ordered system of waves and flashes and rotating pinwheels if you stare at it long enough. And having written a few random-number generators myself, I can tell you with confidence that in the real world there's no such thing. "Random" numbers produced by a machine are inherently deterministic, and with a bit of processing and analysis, they'll give up their secrets and reveal the details of the algorithm which produced them. (This is one reason it's so difficult to produce unbreakable secret codes.)
The situation gets even worse when we consider the layers of statistical abstraction the Princeton team applies to their numbers, before the patterns become visible. There's an old saying in scientific circles: "If you torture the data enough, it will confess." I'm not accusing anyone of anything, but misleading or distorted statistics are a definite risk in any field (and parapsychology in particular, with its history of profit-minded fraud and trickery). Anyway, not even the Global Consciousness Project management itself claims any predictive value for their system, whose precognitive ability—if any—shows up in the form of biased noise, which is riddled with false positive and false negative results. And even if we knew for certain that a "global consciousness" event was coming, we'd have no clues about its nature or location. We won't be using a system like this, for example, to predict murders or terrorist attacks.
The sixth sense can barely be sensed
Telepathy is probably the easiest psi ability to believe in, and to explain scientifically, since the human brain does in fact produce electrical signals which can be detected—and to a certain extent, decoded—by nearby sensors. And interestingly enough, there is better evidence for telepathy than for any other psychic phenomenon.
There are of course a variety of separate, non-verbal channels human beings use to communicate. These include voice stress, facial expression, blushing, body language, subliminal noises, breathing patterns, pupil dilation and pheromones—chemical messengers secreted by the body and picked up by receptors in the nose. The total amount of information carried by these channels is unknown but presumably large, and by itself probably accounts for most of the apparent mind reading we experience in our daily lives.
Couple this with our intuition—our innate and learned knowledge of human behavior—and to a surprising extent, we really can sense the intentions of the people around us. Particularly sensitive individuals—or particularly well-trained ones—may even seem to have a sixth sense about this. The "truthsayers" of Frank Herbert's Dune series are completely plausible, although masking or faking these subliminal signals is another skill some people seem to possess in abundance—especially in politics.
So if some sort of genuine mind-to-mind communication exists, is there any way to separate it from these other factors? Fortunately, yes. An experimental protocol known as the ganzfeld procedure was developed in the 1930s to eliminate (or at least dramatically reduce) these effects. In a ganzfeld experiment, the "sender" and "receiver" are placed in separate, acoustically isolated rooms, and the receiver's eyes are covered and his or her hearing blocked with headphones which produce a disruptive white noise (i.e., static). Then the sender is shown a picture, and the receiver is asked to report any mental imagery, and later asked to choose, from a selection of images, the one which most closely matches their visions during the ganzfeld sensory deprivation. In most cases, the receiver is not aware that the experiment is testing for paranormal abilities.
And the funny thing about ganzfeld is, it actually seems to work. Not perfectly or reliably by any means, but enough studies show enough improvement over random chance that in 1994 Daryl J. Bem, an eminently respectable psych professor at Cornell University, published a paper on the "anomolous process of information transfer," and not in some kooky rag like the National Enquirer or the Journal of Parapsychology, but in the eminently respectable, skeptical and peer-reviewed Psychological Bulletin. In Bem's reports, the average hit rate in certain narrow experiments was 25 percent better than random chance, and as much as 50 percent better in certain individuals—particularly dancers and musicians. This was a landmark in ESP research: The first (and still only) time a reproducible experiment passed scientific muster while still showing a psi or psi-like effect.
Unfortunately, the field's checkered history caught up with this result as well, when Psychological Bulletin published a 1999 "metanalysis" of 30 separate ganzfeld experiments which showed no statistically significant deviations from chance. Bem and others have countered that several of these studies were flawed, and that the inclusion of several more recent experiments would bump the average back up into statistical significance. So while the case remains open, for the foreseeable future the issue promises to remain both marginal and controversial.
The bottom line is that ESP, if it does exist, is an extremely subtle phenomenon whose effects are only slightly discernible from randomness. Call it a touch of good luck—a very slight tendency to guess right, to beat the odds. If ongoing ganzfeld studies continue to show an effect, it's possible we'll discover groups or individuals who are more genuinely psychic, and whose luck is better still. But even if this turns out to be true, my guess is that people whose senses and intuition are well attuned to their environment will have a greater advantage in everyday life. Dreaming of psychic powers is endlessly entertaining, but take it from a rocket scientist: The real magic is in listening to your heart.
Wil McCarthy is a rocket guidance engineer, robot designer, science fiction author and occasional aquanaut. He has contributed to three interplanetary spacecraft, five communication and weather satellites, a line of landmine-clearing robots, and some other "really cool stuff" he can't tell us about. His short fiction has graced the pages of Analog, Asimov's, Science Fiction Age and other major publications, and his novel-length works include Aggressor Six, the New York Times notable Bloom, and The Collapsium.
