Some cause-and-effect sequences are straightforward. Some are more complex. And some are misinterpreted by those who should know better. For a bizarre example of this last phenomenon, I offer you the health activists (variously known as health Leninists, health fascists, and other even less complimentary terms).

When coronary heart disease (CHD) became the latest media bogeyman, the alarmists were keen to tell us all what to do and what not to do. Unfortunately, they were aided by the epidemiologists, who were looking for something else to occupy their attention, now that infectious diseases were becoming so much less common. I say “unfortunately” because the epidemiological model is the wrong one to use. It is the clinician who pinpoints cause and effect by noting and manipulating changes in the individual. The epidemiologists set about comparing entire countries.

There are countless similarities and differences between one country and another, so it’s not surprising that the list of things held in common by CHD sufferers across the world quickly became a long one. By now, there are about 300 of these poorly named, so-called risk factors. They include snoring, baldness, not having siestas, extramarital sex, not keeping appointments, not eating mackerel, having English as a mother tongue, not being a Mormon, slow beard growth, no garlic, and having an intelligent wife. They also include the interesting pair: too much milk, and too little milk.

You might expect that any rational thinker would be able to distinguish between a correlation and a cause. Otherwise the possession of a driving license would have to count as a “risk factor” for a fatal car accident, and learning to swim would be a “risk factor” for drowning. Nevertheless, an entire health-alarm industry has fallen in love with the association game. The belief seems immune to disproof. James McCormick and Petr Skrabanek gathered together the results of all the major intervention trials, and published the resulting tables in the medical journal The Lancet (Oct. 8, 1988). The various interventions manipulated diet, smoking, blood pressure, exercise, and reducing weight, and covered 828,000 man-years. “This summary shows no experimental evidence to support the notion that intervention programs prevent coronary heart disease or reduce overall mortality. . . . Despite this considerable body of evidence, which shows no benefit for intervention, many have interpreted the results as supportive of their wishful thinking.” This review, they say “provides no data to justify the time, energy, and money which are being devoted to this crusade.”

One of the favorite villains right now is cholesterol. Most of the public had never heard of it before the present hit list was drawn up, but now many of them are altering their entire lifestyle and eating habits trying to avoid it. This is in spite of all the evidence showing the pointlessness of any such measures. The result produced by 115,176 man-years of observation was that “lowering cholesterol by drugs did no good and may have done harm.” The same applies to altering cholesterol by diet. In Sweden, for example, coronary deaths in middle-aged men were rising while the risk factors were falling. In a number of countries, death rates for men and women are moving in opposite directions, in spite of the fact that they eat the same foods. In fact, most people with heart disease have a normal cholesterol level.

Skrabanek summarizes evidence presented in the British Medical Journal and The Lancet: “Blood cholesterol for practical purposes has no predictive value for the risk of future heart attack in the individual, and manipulation of blood cholesterol with diet or drugs has no effect on overall mortality, though it may significantly increase the risk of cancer death.”

Do you really want to turn over your life to the heath zealots? G. S. Myers has put together this composite picture of someone with a low risk of CHD: “. . . an effeminate municipal worker or embalmer completely lacking in physical or mental alertness and without drive, ambition, or competitive spirit who has never attempted to meet a deadline of any kind; a man with poor appetite, subsisting on fruits and vegetables laced with corn and whale oil, detesting tobacco, spurning ownership of radio, television, or motorcar, with full head of hair but scrawny and unathletic appearance, yet constantly straining his puny muscles by exercise. Low in income, blood pressure, blood sugar, uric acid and cholesterol, he has taken nicotinic acid, pyridoxine, and long-term anti-coagulant therapy ever since his prophylactic castration.”

All this health advice is not the work of clinical or medical researchers, who know better, but is issued by “health committees,” who vote their list of recommendations into existence. Their unstated motto appears to be (in Skrabanek’s words): “If it is delicious, proscribe it; if it is bland, prescribe it.” K.A. Oster, in Medical Counterpoint, warned that these recommendations, “with wasteful neglect of nutritious foods, such as butter, eggs, whole milk, cheeses and beef, borders on irresponsibility and smacks of medical quackery.”

Another result of “riskfactormania” is that city streets are often littered with joggers, who seem unaware of the most common cause of death among joggers—coronary heart disease. The American cardiologist Henry Solomon estimates that every year about 40,000 Americans drop dead while exercising “for their health.”

Perhaps I should now confess that the Bell Prompt I mentioned in the beginning was the digital watch on my left wrist. In health committee terms, that makes the display on my watch a risk factor for the striking of Big Ben. I shouldn’t take that too seriously either if I were you.

Now there are hundreds of types of Qi Gong: some only need meditation and others require body motion to music. They are popular among Chinese who wish to improve their health and cure their diseases. It is hard to say if anyone has restored his health by performing Qi Gong; while it is also hard to say if Qi Gong is completely ineffective if accompanied by orthodox treatment. Deep breathing, self-controlled meditation, and little movement, which are usually involved in performing Qi Gong, are not harmful.

The cult of Qi Gong, however, is not based on its effectiveness in health care. The “spirit balance” it gives and the quasi-religious mood involved in performing Qi Gong partly accounts for its popularity. Old people may perform it because they have no better ways to spend their time. Around 1985, Qi Gong began to closely connect with another cult—the cult of “special ability”—and each reinforced the popularity of the other.

The phenomenon of SA was first reported in 1978, when the political group headed by Mao’s widow lost its power, and Deng Xiaoping was reinstated and began to advocate the movement to “love, learn and utilize science” in China. This science movement quickly met the needs that the majority of Chinese, including some scholars had. They had forgotten what the rigorous demarcation line of empirical science was. In articles published in many scientific magazines and journals, the coming 21st century was portrayed as a utopian, entirely automated world. The research of UFOs and ETs was regarded as an advanced area of science. Scientific spirit was understood as “to doubt every idea you believe in and to believe in the raw materials you see with your eyes.” This attitude I’d like to name as the “materialist” view on science. (It is not even a Marxist view because Engels disagreed. He believed that observation should be guided by theory, and that idea was quite popular among the scientists and philosophers.)

It was in such a context that the public media reported finding some children who could identify human character by outward appearance—ear, forehead, and nose—and called it “special ability” (SA). The word “special” (Teyi in Chinese) means something a bit different from “paranormal,” the word my American colleagues prefer to use.

The “materialist” scientists believed that SA was not a transcendent phenomenon, but an empirical phenomenon outside of the existing scientific knowledge that could explain and predict; that it could be and should be studied by “scientific method.” In this way the existing laws and theories of scientific knowledge might be challenged and revised. Perhaps it is better to translate the concept of SA as “exceptional ability.”

Although there were some disagreements, the research into SA was booming. More cases were reported and the field expanded to include perception and PK—the ability to bend iron wire in a sealed test tube, or remove pills from a sealed bottle. At the same time, the research into Qi Gong was also booming. New ways of performing Qi Gong were found, such as projecting the Qi out of the sender’s body, through the air, and finally into the body of receivers. These methods were investigated with “scientific” apparatus, including infrared detectors and radiometers. It has been reported since 1984 that Qi Gong could activate the potential SA in people. In 1985, Zhang Hongbao, a master of Qi Gong, proposed the theory of a “cosmic field”; that the energy accounting for both Qi Gong and SA were generated out of and transferred through the “cosmic field” and therefore Qi Gong and SA were unified. Zhang believed that everyone could get SA by training in Qi Gong and that those who had SA but did not know Qi Gong could be taught it. Henceforth, all those who were engaged in the paranormal named themselves “Master of Qi Gong.” Millions of people began to train in Qi Gong, including the youth. The main goal was usually not to heal diseases and improve health, but to get SA and be a “superman.”

In 1987 and 1988, Yaniments by a group at Tsing Hua University were published in scientific journals that “verified” that Qi could be sent out over 2,000 kilometers to hit the targets—a polariscope and a reagent in a test tube—and change the direction of the polariscope axis and the molecular structure of the reagent. The scientific community was shocked by these results, and even more so when it was discovered that those who engaged in these experiments were only amateurs. The authorities at Tsing Hua University had failed to realize that the group represented the university.

Another creation of Yan Xin was the “Talk Show with Gong.” Hundreds, even thousands of people came to listen to his lecture and were induced by some unexplained forces to sway, quiver, sob, grin, sleep, and express other emotions at the lecture. Such induced emotions were believed to be good for health. The “Talk Show with Gong” was quite popular from that time on, and the recorded tapes of Yan’s lecture were claimed to carry the information of Qi Gong. They sold very well around the country.

Yan Xin attributed SA to Qi Gong. His theory was that the children who had SA were not talents but that there were some masters of Qi Gong sending Qi to them in secret. Yan also expanded the effectiveness of Qi Gong’s psychokinetic powers to include moving away tons of fish, changing the weather, and putting out a forest fire.

After 1988, Qi Gong became more influential. In 1990, a woman master of Qi Gong, Zhang Xiangyu, pushed its influence to a peak with her performance in Beijing. Millions of “pilgrims” gathered from several provinces to see her and caused great traffic jams. When Zhang waved her hand out of a window of the third floor of the hotel, the “pilgrims” in the street cheered. Zhang claimed that she could talk with extraterrestrial beings and was able to cure every disease. She treated her patients with methods similar to those of witchcraft and demanded large amounts of money from them. Many patients became ill under her treatment and some of them died. In August, Zhang was arrested and accused of cheating. The exposition of her swindle weakened the cult of Qi Gong. Zhang was convicted in 1993.

Soon after the arrest of Zhang Xiangyu, a conscientious master of Qi Gong, Sima Tu, told the truth about the various kinds of Qi Gong hoaxes. The prestige of Qi Gong dropped rapidly and became merely a sort of body exercise popular among old people, as I mentioned at the beginning of this article. However, Qi Gong staged a comeback in a different form after 1992, as a trend of thought instead of a practical movement. In this way it has much to do with the revival of the paranormal in traditional Chinese culture.

The renaissance of traditional culture began in 1989, when the government found it useful as an ideological weapon to fight against Western-style liberalism. Moreover, it seemed to be a hopeful alternative to orthodox Marxism as an ideology to join people’s viewpoints with feelings. The preference for traditional culture in literature, however, can be dated back to 1984. Then, some novelists announced they were able to “find the root for our literature” when they felt disillusioned by the importation of Western literature and art since 1978, as well as Marxism, which is also a western ideology. The announcement of finding the “root” is not a bad one.

When the government took part in the revival of traditional culture, things turned out to be worse, because the leadership of government was far from being scientific and rational. A manifest example was the “I Ching” craze beginning in 1989. An ancient classic about divination, the “I Ching” relates something of the philosophy, beliefs, customs, and mathematical ability of ancient China. But in the recent craze it was claimed to have the implications of modern physics, mathematics, astronomy, and computer science.

For example, it is said that G.W. Leibniz (1646 - 1716) got inspiration out of the Eight Diagrams to create the binary computer and had sent one of his machines to Emperor Kang Xi of the Ding Dynasty. This claim turns out to be completely false. The binary computer wasn’t created until 1941 (the Z-3 machine). What Leibniz created is the binary system, and he worked it out before he saw the Eight Diagrams.

While the cult of traditional culture led to pseudoscience in intellectual circles, it resulted in the revival of primitive superstition, such as fortune telling, astrology, physiognomy, and “I Ching,” ancestral worship, and magic among the masses with less education. They abounded in the broad rural areas, as did the Qi Gong in the cities. The official newspapers warned that “the superstition of feudal ideology is reviving in our countryside.”

From the standpoint of the official media, superstition refers to something more than we have mentioned above. It includes the spontaneous, disorganized minor religions in the rural areas. For instance, hundreds of pamphlets on Zen have been issued since 1990. Zen, as a specific religion originating in China and spreading over the Far East, was generated out of the mixture of Indian Buddhism and Chinese traditional thought. It had benefited from Taoism, Confucianism and other traditional Chinese teachings. Therefore Zen, as well as Taoism and other religious traditions, became popular with the revival of traditional culture. These traditions should be highly appreciated in themselves but the popular interpretation of them came to include the paranormal.

A typical case is the book The Decoding of Liuman’s Mysteries (Renlei Shenmi Xianxiang Poyi, 1992) by Ke Yuniu. In it, he announced that he had encoded all the mysteries in human history: Qi Gong, Yoga, SA, psychic phenomena, parapsychology, magic, soul, I Ching, Chinese medicine, Laozi and Dao De Jing, Zen, Sakyamulli and Buddhism, the Bible, Jesus and God!

Carefully read, one can uncover that Ke’s thoughts never transcend the ideas of the early sages, such as Laozi, Sakyamuni and Jesus. He borrows from Zen epistemology, makes use of Laozi in the ontology, believes Qi Gong as an alternative to physics, and he also contributes his own illogical methods of thinking.

In November 1994, Ke issued his new three volume book: Research Into Life. In this book he proposed few new ideas but described hundreds of “successful” experiments to verify the presence of SA. In general, Ke’s books are not worth being treated seriously; but their great influence on the social ideology is dangerous, and we need to deal with them.

The movement to “love, learn and utilize science” from the end of the 1970s unexpectedly helped the growth of pseudoscience. The above-mentioned “materialist” view of science was an important cause, another was that public education in science was led astray in this period. The masses were given “scientific knowledge” without the necessary explanation of how it was achieved. That no method was available for the masses to decide whether a claim was scientific made them turn to some “authoritative” source, for example, the public media, an administrative organ, or the “mystery authority” relating to the intelligence agencies and the military.

“Hongcheng Magic Liquid” is a case of “mystery authority.” Being an ordinary man in Northeast China without higher education, Wang Hongcheng, in the early 1980s, pretended to have created a sort of “liquid” of which two to three drops could change the structure of one liter of water to make it as combustible as petrol. Were his claim true the words “energy crisis” could be canceled from the dictionary eternally. The Chinese security and military departments paid much attention to the declared creation and funded Wang for further research. When it was shown to be obviously a fraud, Wang was thrown into prison. However, he became a legendary figure. Some people believed that Wang was persecuted because he refused to turn over his “secret” formula to the government, and that this was covered up.

When Wang was finally freed, many news reporters, worshippers, investors, and crooks gathered around him to hear about the “secret” formula. In 1992-1993, Wang was rather popular on the public media, and he set up a company to develop the “Hongcheng Magic Liquid.” Nothing happened in the end, of course.

Another case has more to do with the authority of administrative organs. It is the “W-Shape Ship Patent” belonging to Zhou Jinyu from South China. He was a young technician and announced his innovation in 1985. This was to put the propeller in the middle of a ship instead of at the stern and to give the whole ship a W-shape. Zhou claimed that he had discovered a new fluid theory, by which the W-shape innovation could improve the speed of ships by 200 to 300 percent, but he had never published a paper about his “theory.” Experiments performed by some experts indicated that a ship when applied with this innovation would lose 20 to 30 percent of its speed and risk turning over. However, Zhou managed to get a formal appraisal from the local administrative committee of science and technology. He succeeded in bypassing the patent bureaus, the local government, public media, and entrepreneurs, simply by waving the appraisal. A large amount of money was wasted in making W-shaped ships, because they couldn’t move at all. Zhou was awarded and honored by governments at different levels until he was exposed by thirty scientists in 1992.

In the 1990s, as China accepts the market system step by step, the public media plays more and more important roles in the spread of pseudoscience, and cases of pseudoscience increase in the area of business. The Chinese people haven't developed the necessary skeptical view of advertising, and the lack of related laws provide cunning businessmen with an open field. Until November 1994 China didn’t have a law for truth in advertising. The public media abounded with fraudulent advertisements. One example was the “electronic adding-growth shoe pad.” This shoe pad was said to help short young men grow taller by stimulating specific parts of the sole of the foot.

Another case was the “electronic stutter-curing instrument,” which was only a micro-amplifier, to enable you to hear your own voice through an earphone attached.

Fraudulent advertisements have been reduced since the Law of Advertisements went into effect, but pseudoscientific businesses, especially in the field of medicine, haven't been contained. First, an essential system to test the quality of new medicines has not been established. New medicines always have to “pass” a clinical test, but the necessary control group is usually neglected, or the it is not under rigorous control. For example, all the patients of the control group haven't been given the same dose. Second, the effectiveness of Chinese medicines cannot be tested by orthodox procecare articles” insteading disease instead of caring for health.

The Chinese medicine and “health care articles” market has been full of various sorts of oral liquids. They all claimed to be able to reduce your white hair, or improve your memory, or strengthen your sexual ability. One of them is called “China Soft- Shelled Turtle Extract.” It is well known that female Chinese long-distance runners have continually been winning the championships in different races and often also win and as the runner-ups. It is also well known that all these female athletes are guided by the same coach, Ma Junren. Ma’s method in training is peculiar, but public opinion holds that he has a certain “secret formula.” In the West, reporters guess about the stimulant used. In China, people noted that Ma had his athletes drink the blood and fat of soft-shelled turtles everyday. A financial group in Chang Zhou announced that they had bought the “secret formula” from Ma and began to produce the extract. However, a group of reporters recently discovered that no turtles could be found on the production line.

Besides, Ma had sold his “secret formula” to another company for two million Juan (about $250,000). Turtle, of course, is not among the ingredients. This company is now selling a liquid named “Life Atomic Energy,” which is said to be produced according to Ma’s direction.

In my view, the most influential commodity and the first object that ought to be inquired about in the present China market is the so-called “Life-Spectrum Healing Instrument.” According to its creator, Zhou Lin, it can emit rays whose spectrum is similar to the emission spectrum of the human body. Thus it “adjusts the balance of the human body system.” This explanation for its mechanism is not clear. If its spectrum is really in accordance with the human’s emission spectrum, we can understand that the energy of the rays is subject to absorption by the body, that it will heat the tissue inside of body.

Perhaps it is a better physical healing method than the traditional hot compress, but this wouldn’t help us to understand how it could adjust the balance of the body system.

In fact, Zhou’s instrument hasn't been strictly investigated. It is widely accepted primarily because it won the first prize in an international fair. The general underdevelopment of Chinese science and technology induces people to be convinced by the “authority” from any international organization.

On December 5, 1994, the State Council and the Committee of the CPC issued a proclamation to strengthen public education in science. In this proclamation it was recognized that “public education in science has been withering in recent years, at the same time activities of superstition and ignorance have been growing and antiscience and pseudoscience cases have frequently been happening. Therefore effective measures must be applied as soon as possible to strengthen public education of science. The level of public education in science and technology is an important sign of the national scientific accomplishment, and is a matter of overall importance relating to the promotion of the economy, the advancement of science, and the development of the society. We must pay attention and carry out the public education with consideration of a strategy to modernize our socialist country and to make our nation powerful and prosperous. Ignorance is never socialist nor is poverty.” It is planned to advocate education with the three aspects of science: scientific knowledge, scientific method, and scientific ideas. This proclamation greatly encourages the rationalists, and has formed a helpful context for attacking the paranormal. However, it is possible that such a government- guided movement would turn out to be politically oriented. If the paranormal was only suppressed by the political power, and if people were not to be persuaded reasonably to discard their irrational beliefs, the matter would be worse. In my view, political intervention is the most dangerous element of skepticism, and it could result in many more cases of paranormal claims.

This shows up in all sorts of ways, and not just in the supermarket checkout journals. On KYW, Philadelphia’s leading radio news station, I often hear things like: “A fire was reported in the 2800 block of West Cumberland Street, in the Kensington section of the city.” But every true Philadelphian knows that if it is Kensington, it has to be East Cumberland Street. Clearly, their writer is an immigrant fresh from the hinterlands and is ignorant of the city’s geography.

Headline writers are the worst perpetrators, and often behave as though they have not read the story they are headlining. There was a recent spate of articles in the papers about sonoluminescence, a process in which powerful sound waves in a liquid produce air bubbles within that liquid; simultaneously shock waves are produced inside the bubbles that heat the compressed gas to very high temperatures. As a result, the compressed gas emits flashes of light, as any heated gas will. Each light flash lasts less than 50 picoseconds (1 picosecond = 10 -12 seconds). The announcement of this discovery was accompanied by a reasonable conjecture that if you used heavy water (deuterium oxide) as the fluid, you could produce thermonuclear fusion by this method and so generate energy.

So far so good. However, in his or her enthusiasm, the headline writer added the word “cold” to the caption, thus creating an overheated announcement that the experimenters had achieved “cold fusion.” But the body of the story clearly explained that the fusion reaction would occur because of the high temperatures within the bubbles. Automatically the headline writer assumed that if it took place in a beaker of water, it had to be cold fusion. Two kinds of errors were involved. One, the headline writer did not read the story carefully; two, the headline writer did not understand that even in a beaker of cold water there can be local and temporary regions of high temperature (although it is clear that continuous application of these high energy sound waves is going to heat up the water pretty fast).

P.S.: Experiments are under way at Lawrence Livermore National Laboratory to do this experiment with deuterium and to try to generate measurable neutrons.

Now let us examine a story published in a prestigious news journal: Newsweek, dated Dec. 26, 1994. On page 108 we see an item that is a prime example of what happens when a couple of English majors try to deal with a science- based story. (I am assuming they are English majors, having only their ignorance of science as evidence. Whatever happened to the idea of having science writers who major in science and so know what they are writing about?) The article is about powering vehicles with fuel cells, part of a series predicting the next century. A fuel cell is described as “a sort of battery that never needs recharging.” True, it never needs recharging, but that is because it derives its energy by oxidizing liquid or gaseous fuel. Its main virtue is touted as no release of pollution to the atmosphere.

The falsehood lies in what is left out. We are told: “Fuel cells make possible the dream of running a car on water: separate water into H₂ and O and, presto—car fuel.” Unmentioned is the fact that to separate water into its elements requires that you put in as much energy as you get out when you burn the hydrogen and oxygen. And generating that initial energy is going to produce a certain amount of pollution.

Notwithstanding, the authors end with an upbeat. After predicting unlimited and cheap energy from fuel cells in the future, we are told: “And then fuel cells would be even more like a perpetual-motion machine: all the electricity you want without a speck of pollution.” A schematic diagram of a fuel cell inspires the writer to even greater heights. Its caption tells us: “A fuel cell is the chemical version of a perpetual-motion machine.” All this hype disregards the fact that fuel cells have not the slightest similarity to perpetual-motion machines. The defining feature of a perpetual-motion machine is that it produces energy without burning fuel-that is, it would if it existed. But a fuel cell burns-or at least oxidizes-fuel. Certainly if perpetual-motion machines existed they would operate without pollution, but that is incidental to the main point. To compare a fuel cell with a perpetual-motion machine because they are both free of pollution is like saying a centipede is like a lion because they both have legs.

It is clear that the authors needed some sensationalism to puff up a fairly prosaic story. They did this by using the term “perpetual-motion” as though this machine really exists. Actually, since perpetual-motion machines do not and cannot exist, the comparison of a fuel cell with a perpetual-motion machine might be taken to mean that fuel cells do not exist either. Which is not true.

Fuel cells are indeed an active area of research. They have been used for years in space vehicles. Efforts are now aimed at using natural hydrocarbons, such as gasoline or methane, for fuel instead of pure hydrogen. Once the price is reduced from $2,000 to $50 per kilowatt, there are two advantages: less pollution and greater efficiency than with internal-combustion engines. The efficiency of heat engines is limited by the laws of thermodynamics to a low value, while a fuel cell, which does not go through a heat cycle, can approach 100 percent efficiency. But in no way can it be likened to perpetual motion. Now look at the obituary for Eugene Wigner that appeared in the New York Times on January 4, 1995. Wigner was one of the 20th-century giants of theoretical physics. His work in nuclear theory earned him the Nobel prize in physics for 1963. In describing his interest in quantum theory the obit says: “In the ordinary world, an object either exists or does not. But quantum theory provides that something at the subatomic level can both exist and not exist simultaneously.” I know of no textbook on quantum theory that makes such a statement. This kind of thing is typical of certain intellectual types who say things like: “Nothing exists until it is observed.” Which I trashed in my last column.

Quantum theory does say that the state of an object is undetermined until it is detected, so that you might think of a photon reflected from a half-silvered mirror as going in two directions simultaneously (the reflected wave and the transmitted wave) until a photodetector places it in a definite location. But that does not mean the existence of the photon is in doubt.

I’m sure, however, that this new myth will remain in circulation forever.

Effects pioneer Willis O'Brien made the giant-creature shots in King Kong using a technique called stop-motion animation. Stop-motion animators pose flexible model creatures (apes, dinosaurs, what have you) in miniature settings and expose a single frame of film. Then they move the creatures into the positions they would have assumed 1/24-second later if actually in motion, expose another frame, and begin the dreary round again. It’s laborious, but for decades it was the only way to bring truly outrageous objects “to life” in the cinema.

The thing to remember about traditional stop-motion is that none of the “moving” subjects are actually in motion when they are photographed. But an illusion of motion arises when the human eye views these still pictures, twenty-four of them each second, on a motion picture screen. (The numbers differ for video, but the same principles apply.)

Stop-motion is far from perfect. To see why, we must consider how motion picture images are created—and how the brain interprets them to produce the illusion of motion. A motion picture camera operating at sound speed exposes twenty-four frames per second (FPS). It’s a purely mechanical process— advance the film a frame, stop it, open the shutter, close the shutter, advance to the next frame—so less than half of the time between frames is available for exposing the film. The actual exposure time for a frame of motion picture film is about 1/60- second. If you've used a 35mm still camera that lets you set your own shutter speeds, you know 1/60-second isn’t very fast. If you photographed a basketball game at that shutter speed, you'd get blurry images of the players. To get stills that freeze the action, you'd want a faster shutter speed — say, 1/500-second.

Why do moving objects blur with exposures in the 1/60- second range? Imagine photographing a passing car. At 60 mph, the car moves 88 feet per second, almost a foot and a half during the 1/60-second that your shutter is open. How will the car look when the prints come back? It will blur, of course, reflecting the fact that the car was not in the same place throughout the exposure. Blur severity varies not with an object’s absolute speed, but with how much of the image area it crosses during an exposure. Set your shutter at 1/60-second, stand 200 feet from a superhighway, and snap a picture. The cars will only blur a little. Stand on the shoulder and snap that same traffic, and you won’t be able to tell Fords from Toyotas.

When it comes to blur, Hollywood movie cameras work just like your still camera at 1/60-second. They just cost more. Pop your favorite movie in the VCR. Freeze a single frame of an action scene. You'll see blurring you never imagined was there. But your brain notices it. More, it expects moving objects to be blurry.

That brings us to the question of how the brain interprets the projected motion picture image. Everyone knows the basic principle: Successive still images are flashed on a screen, and a phenomenon called “persistence of vision” keeps us from seeing the intervals of darkness between frames. We view the succession of stills as a continuous image. When an object changes position from frame to frame, we perceive that the object is in motion. But this isn’t the only cue that can fool the visual system into perceiving movement. 3-D movies exploited stereoscopic vision to create vivid impressions of movement. Conventional movies don’t take advantage of stereopsis. But they do take advantage of other assumptions the brain seems to make about moving objects. One such assumption is that the image of a fast-moving object will be degraded as a consequence of its movement. In other words, if an object is moving quickly enough across the visual field, the brain expects it to blur.

Keeping that in mind, we can reconstruct why the pilot’s- eye view shot in King Kong looked so good, and why the smash- the-airplane shot looked so bad. Since subjects in classical stop- motion do not move during exposures, they do not blur. For the pilot’s-eye view shot, Willis O'Brien rigged a stop-motion camera to roll down a track over a huge New York skyline diorama toward a model Empire State Building. Though the camera seemed to move at 150 mph, since the objects in motion relative to the camera (the skyline) were distant, nothing moved very far across the image area between any two frames. If the shot had been staged for real, you wouldn’t expect much blur. So the fact that the stop-motion sequence had no blur did not detract from the illusion of motion it created.

The smash-the-airplane shot was a fairly close, static shot. The airplane sped across the screen; Kong’s arm lashed out and struck it. With each frame, they crossed large fractions of the image area—normally a recipe for severe blurring. But stop- motion can’t blur! When viewing this scene, we experience conflict between two modes of visual interpretation. Objects change positions drastically from frame to frame, which tells the brain that they are moving quickly. But the absence of blur tells the brain that everything is stationary. Result: interpretive conflict. The illusion of motion is compromised.

Stop-motion shots that don’t have the blurring they need give viewers a “strobing” sensation. Objects jerk-jerk-jerk like dancers under an old disco strobe light. Three famous scenes created by stop-motion master Ray Harryhausen in the 1950s and 1960s exemplify the problem. Next time you find Jason and the Argonauts on late-night cable, watch how the swordfighting skeletons “strobe,” especially in close shots. Check out the jerky movements of the giant crab in The Mysterious Island. In One Million Years B.C., a stop-motion pterodactyl carries off Raquel Welch. Its wings flap in and out of frame at high speed—but with no blur. Even to untrained eyes, it looks profoundly wrong.

In the next installment, we'll see how moviemakers since the time of Star Wars have applied high technology—and sometimes, startlingly low technology—to inject blur into animated footage. Understanding how and why Hollywood professionals use blur to make their illusions more effective can help us all understand the myriad ways the eye can be fooled.