The first thing we notice on arriving at the 24th World Championship of Magic in Beijing is that the massive building where it’s being held—the China National Convention Center—is all smoke and mirrors. It’s not that there’s something wrong with the air handling system, or that a magician used too much dry ice during his act. Rather, the edifice was constructed with mirrored panes of glass that, in the high heat of July 2009, trap huge shrouds of urban smog. Outside, it’s worse. The entire city of Beijing is blanketed in smog so thick that you feel as if everybody and everything around you is an apparition emerging from behind a magician’s smoke machine.
Plenty of venues award magicians for their skills, but the World Championship of Magic is the preeminent international event. Held every three years in a different country by the Fédération Internationale des Sociétés Magiques (FISM), this competition is informally known as the Magic Olympics. The weeklong contest is where magic stars are created. Winning a grand prize here is akin to receiving an Oscar; it’s a guarantee of steady work for years to come. Many talented young magicians such as Lance Burton have gone from obscurity to world-class fame at the Magic Olympics. We’re here to see it happen with our own eyes, and it’s quite a scene. Twenty-five hundred amateur and professional magicians, purveyors of magical paraphernalia, and curious onlookers from sixty-six countries amble through the main lobby and corridors on their way to huge festooned halls where the ceremonies and competitions are being held. Their attire ranges from standard street clothes to wizard’s robes and everything in between.
Some people attend lectures given by famous magicians on topics such as “From chaos to order: different methods to secretly arrange the cards into special order,” “Japanese style on how to study magic,” “How to present the same trick three different ways,” and “Boldness and magic, or the art of having real nerve.” Others roam between booths selling rope and card tricks, fake appendages of all types, magic trick books, special order card decks, stage gimmicks … everything a magician could ever covet.
One hundred performers are competing for the grand prize in the two main categories of stage magic and close-up magic. Stage performances are judged on manipulation, general magic, stage illusions, mental magic, and comedy magic. Close-up performers are rated for card magic, parlor magic, and micromagic (magic tricks done on a very small scale, such as small coin tricks or tricks with toothpicks).
Two days into the event we are thrilled to spot Max Maven, one of the world’s greatest living mentalists, sitting in front of the overflow screen in the main hall outside the competition rooms. Maven is legendary for his ability to read minds. Onstage he assumes a sinister Svengali look: thick black eyebrows arched high with disdain, a clipped Fu Manchu mustache, and a meticulously shaved widow’s peak. He has an extremely high, heart-shaped forehead, pointy ears, a deep baritone voice, and salt-and-pepper hair pulled back into a taut knot from which a long braid hangs down his back. To complete his look, Maven wears black double-breasted suits, black shirts, and bold silver bracelets and rings.
But today Maven is in his street clothes—black T-shirt, black pants and boots. His samurai hair is loosely braided and almost reaches the floor. It is late afternoon and beams of sunlight are shining into the convention center’s halls like pillars of gold in a cathedral. A large sign—RM 319, RESTAURANT AND MAGIC SALON—hangs on the wall.
Maven is relaxing and watching a twenty-foot-high movie screen where a young magician from Sweden is producing card after card after card from an empty outstretched hand. Our son Iago has fallen asleep in his stroller, so we roll over to Maven. We’ve got a question ready for him: Does he know any multisensory tricks? That is, can he tell us about tricks that rely on interactions among the different senses such as vision, hearing, and touch? Maven is pleased with the query and responds by telling us a classic joke used by generations of magicians to entertain friends and family. It’s the Dinner Roll trick.
Here’s his description: To begin, the magician is seated at a dinner table covered with a cloth. He makes sure that you are in front of him, unable to see his movements behind and below the cloth. He says something corny like “You know it’s rude to play with your food. But I wonder if this soft dinner roll will bounce?” He holds the roll in his hand and flings it to the floor. You hear it bounce with a loud thunk and then fly back up into the air, where he catches it.
SPOILER ALERT! THE FOLLOWING SECTION DESCRIBES MAGIC SECRETS AND THEIR BRAIN MECHANISMS!
The secret behind this very convincing illusion is simple. The magician sits across the table from you, turned away from the normal eating position. The magician’s hand makes the motion to fling the roll to the floor. As soon as his hand and lower arm are out of your view, he turns his hand over, palm up. Using his fingers and wrist, he launches the roll back up into the air, making sure not to move his upper or lower arm. All the action is in his fingers and wrist—and in his foot. Before the roll reappears in midair, the magician taps his foot. You hear the thunk at the same time the roll would have hit the floor.
But what makes the dinner roll trick really interesting is a twist performed by the magician Jay Marshall. He put an extra delay between the sound of the roll hitting the floor and its bounce back up. It’s as if the roll dropped down below the floor before it hit and bounced back up. This maneuver heightens the illusion, and nobody notices the discrepancy.
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In movies, technicians called Foley artists artificially exaggerate everyday sounds to make them more realistic. For example, they might re-create the sound of walking in the mud by rhythmically squeezing a wet newspaper in time with the screen actor’s footsteps. A recent study showed that listeners deem such modified sounds more realistic than recordings of the actual event more than 70 percent of the time. Susana witnessed this when she joined a gym to practice tae kwon do (a Korean martial art) at the age of fifteen. On her first day she was surprised to find out that unlike punches in action movies a real-life punch doesn’t make much noise.
Another multisensory trick popular with dinner table magicians involves a disappearing saltshaker. Again seated across the table from you, the magician puts a quarter on the table and says, “Would you like to see me make this coin go through the table?” Of course you would. The magician explains that he’ll need a bit of help moving the coin. He takes the saltshaker, wraps it snugly in a dinner napkin, and taps the coin. Tap tap. He moves the napkin-clad shaker back toward his body. Nothing happens. The coin is still there. He repeats the tap tap and movement of the shaker. The coin has not moved. He does this a third time, saying, “Oh, my, this is difficult,” and leaves the shaker on top of the coin. Then he takes his hand and wham, he slams the saltshaker right through the table. At least that is what it looks like. The saltshaker is gone. The napkin is flat and the quarter is still on the table.
SPOILER ALERT! THE FOLLOWING SECTION DESCRIBES MAGIC SECRETS AND THEIR BRAIN MECHANISMS!
This trick, too, is simple. The second time the magician pulls the saltshaker back toward his body, he deftly takes it to the edge of the table and drops it into his lap. Because the napkin retains the shape of the shaker, you assume it is still in his hand, within the napkin shroud. Meanwhile, the magician uses his free hand to move the actual saltshaker under the tabletop to the position directly below the coin. He makes a third tap tap tap motion with the napkin, but this time the sound actually comes from below. When the magician slams the empty shaker-shaped napkin flat, your sense of vision and hearing together create the perception that the saltshaker has passed through the table. It’s a profoundly convincing combination.
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These two tricks reveal a fundamental property of your brain: your propensity to integrate information from multiple senses as you interact with the world. When you simultaneously see a bright light and hear a loud sound, your brain figures they are related. Recall that illusions occur when the physical reality does not match the perception. If you see cymbals banged together and hear the resultant crash, it’s not an illusion. But if you’re in Boston for the Fourth of July celebration and you see the Boston Pops cymbals banged and hear only the howitzers firing during Sousa’s crescendo, it’s an illusion.
The fact that your brain combines sights and sounds into single perceptions seems patently obvious, but for neuroscientists the phenomenon is surprisingly complicated. From Aristotle on, researchers have tended to study senses—sight, hearing, touch, smell, taste, balance, self-motion, and feelings from the body—in isolation. Magicians, on the other hand, have learned to manipulate perception by understanding when and where the senses don’t mix accurately.
Are senses really separate? When you encounter the world, your experience is not disjointed. When you perceive a barking dog, you don’t feel you are seeing it with one channel of your brain and hearing it with another. In general, when combinations of sounds, smells, tastes, lights, and touches occur simultaneously, you perceive a coherent multisensory world.
Senses not only interact, they enhance one another. For example, what a food sounds like can determine how it tastes. Potato chips are yummier if they make more noise when you bite into them. Bacon and egg ice cream (sorry, the experimenters are British) tastes more bacony if you hear the sound of bacon sizzling in a pan, more eggy if you hear chickens clucking in a farmyard. Oysters taste better when you listen to seagulls and crashing ocean waves.
The same goes for skin and sound. When you say a word that begins with the letter p, t, or k, you produce a puff of air that is sensed by mechanoreceptors in human skin. The puff of air helps you and others perceive the sounds correctly. This rather amazing fact was revealed in a recent series of experiments. If you were a participant, you would sit in a chair while researchers delivered tiny puffs of air to your ankle and played the sounds pa and ta. You would hear pa and ta. But when they played pa and ta without the puff of air, you would more likely hear ba and da.*
Your eyes can fool your ears. Check out the McGurk effect.† In this auditory-visual illusion you will see a film clip of a man saying “da da da.” But if you close your eyes, you will hear him saying “ba ba ba.” Then if you mute the sound and just watch his lips, you will clearly see that he is saying “ga ga ga.” The effect is amazing. It happens because your brain does its best to reconcile mismatching information whenever it can. Sometimes your brain’s best is not good enough to be accurate. But then again, it is very unlikely that you will ever see “ga ga ga” and simultaneously hear “ba ba ba” in nature. The reason these effects work is that your brain takes shortcuts to make likely interpretations of perceptions occur faster. Thus, although the resultant perception may not be accurate (it’s an illusion because the perception does not match the physical reality), the illusion is accurate enough and has helped humans to survive by saving brain processing time and effort as, for instance, your ancestors listened for leopards prowling in the nearby bushes.
Your ears can also fool your eyes. If you look at a single flash of light while hearing multiple beeps, you may see multiple flashes. In the same vein, what you hear influences what you feel. In the parchment skin illusion, you rub your palms together while listening to different sounds. Higher frequencies will make you feel as if your hands are rough. Lower frequencies give you the impression of your hands being smooth, although nothing about them has changed.
How you feel the world can actually change how you see it and vice versa. Remember the waterfall illusion from chapter 1? If you stare at the downward motion of a waterfall for some period of time, adjacent stationary objects such as rocks appear to drift upward. But if you feel an up or down sweep on your fingertip as you watch the waterfall, the perceived direction of water flow switches. Touch alters vision.
And then there is the rubber hand illusion, which you can try at home. First you need to buy one of those creepy rubber hands from a Halloween store. Let’s assume it’s a right hand. Sit at a table and place the hand on the table where you can see it while putting your own right hand in your lap, out of sight. Ask a friend to take two soft paintbrushes and simultaneously stroke your real hand and the rubber hand with the same rhythm. If you are like many people, you will soon feel that the dummy hand is your own. If your friend smashes the rubber hand with a hammer, you may scream Ouch!* With the proper equipment, including a virtual reality headset, you can even induce an entire out-of-body experience based on this illusion.†
A surprising number of people experience unusual multisensory perceptions because of the way their brains are wired. One sensation, such as music, triggers another type of sensation, such as taste. Senses are cross-activated. For example, some people perceive letters or numbers as having color. For one person A is always red, B is always turquoise. For another person, 7 is always yellow, 4 is always orange. Days of the week can possess personalities: Tuesday is sad, Wednesday is happy. These associations are idiosyncratic and automatic, lasting a lifetime. The phenomenon is called synesthesia.
Neuroscientists have identified at least fifty-four varieties of synesthesia, including some that are quite common. People with auditory synesthesia hear sounds such as tapping, beeping, or whirring when they see things move or flash. This trait was discovered accidentally when a student participating in a study of visual motion reported hearing sounds when observing a scene similar to the opening of Star Wars, when the stars fly out at you, but in this case there was no sound track. Researchers soon identified many other students with the same cross-sensory perceptions. It seems that some people have an enhanced sound track to life, which makes sense when you consider that in the natural world many moving things (say, a bee) make sounds when they move (buzz).
In time-space synesthesia, a visual experience can be triggered by thinking about time. Like Kurt Vonnegut’s Tralfamadorians in Slaughterhouse-Five, some people can literally see time. For example, some say they view a year’s time like a circular track with them standing in the middle. They can see the days and months unfolding all at once.
In mirror touch synesthesia, which is rare, people experience sensations of touch on their own bodies when they see other people being touched. They sense a slap on their shoulder when they see another person get slapped on the shoulder. Same goes for a kiss.
Synesthesia runs in families, suggesting a genetic origin to the condition. It is common for family members to experience different types of synesthesia and for the trait to skip generations. Research shows that synesthesia is caused by increased cross talk between various brain regions as well as extra connective pathways linking them.
As for the rest of us, synesthesia offers insights into our everyday perceptions. All of us have our sensory wires crossed to some extent, if only to process multisensory inputs. Look at the two shapes on the following page. Which one would you call bouba and which kiki? If you are like the vast majority of people tested from a wide variety of language groups, you will identify the rounded shape as bouba, maybe because your mouth makes a more rounded shape to produce the sound. When you articulate kiki, your mouth is more angular with the harder sound of k. Such synesthesia-like mappings may be the neurological basis of how sounds are mapped to objects and actions in the world.
The bouba kiki effect was first described in 1929 by Wolfgang köhler. The vast majority of people identify kiki with the angular figure and bouba with the rounded one.
Magicians intuitively know that your senses interact. They know they can fool you by the sound of the dinner roll hitting the floor and the sight of it bouncing back up into the air. When the magician pretends to throw the bun on the floor, you hear a thunk and perceive the act as having happened. Your brain integrates the sight and sound of the bun into a single perception: it landed and bounced. It is a multisensory illusion. By adding a delay, magicians discovered how to make the roll into what scientists call a superstimulus. They are live-action Foley artists. Similarly, when you see the saltshaker-shaped napkin tap the table and hear the sound of tapping, your brain integrates the sight and sound, leading to an auditory-visual illusion.
A superstimulus is a supersalient object or event that evokes a stronger neural and behavioral response than the normal stimulus for which the response evolved in the first place. It’s supersized fries when you’re hungry. It’s an ice-cold pint of beer when you’re thirsty. It’s the extreme curviness and abnormally large breasts of the prehistoric Venus of Willendorf. It’s mascara and lip gloss on a sexy female face (remember from chapter 3 that increasing the contrast of eyes and lips produces the illusion of making a face look more feminine). Super-stimuli invite attentional focus. Jay Marshall realized that the timing of the roll hitting the floor was the key to the illusion. By increasing the delay enough to engage interest, but not enough to generate an incongruity, he made the bounce of the dinner roll seem more magical.
Multisensory integration is an ongoing and dynamic property of your brain that occurs outside conscious awareness. So, where in your brain does the cacophony of sensory information come together? Your senses are separate, in that your eyes, ears, nose, skin, and tongue are located on different parts of your body. But your experience is coherent, integrated, and usually unambiguous.
The Venus of Willendorf is a female superstimulus from more than twenty thousand years ago.
Part of the answer is that you possess multisensory neurons. Just as you have neurons that specialize exclusively in vision, hearing, or touch, you have neurons that fire in response to simultaneously occurring sights and sounds, touches and sounds, touches and sight, and so on for all aspects of sensory processing (including balance and pain and the location of your body in space).
Multisensory neurons are found throughout your cortex, even in areas thought to specialize in a single sense. For example, several brain regions traditionally thought to be visual areas have multisensory neurons that fire in response to sounds and/or touch. And a midbrain region called the superior colliculus is densely packed with multisensory neurons that map out your brain’s responses to all of these senses. Superior colliculus neurons extract clues from multiple sources, including multisensory neurons in your higher cortex, and help you orient your head and body to what’s important in the world at any given moment.
Have you ever driven a cat crazy with a laser pointer? The cat will chase the little red spot up a wall, under a rug, behind a couch, or wherever you point the thing. It’s great fun for feline and human alike. Researchers recently borrowed this game to run a multisensory experiment. Cats were trained to look straight ahead and then approach a very low intensity light, which was a very demanding task. But when the scientists added a brief, low-intensity burst of noise from the same location as the light, the cats performed brilliantly. When the researchers added a soft sound from another location, the cats failed miserably.
Now imagine a cat hunting mice in the dark. The rodents make soft skritching noises while the cat’s sensory whiskers sweep the environment. For a cat, whiskers are better than eyes. By combining sound with whisker motion, the cat triumphs. The lesson for mice: keep silent.
But a deeper question remains. While multisensory neurons can combine inputs from your different senses, they are still widely located throughout your brain. It’s not plausible that every multisensory neuron is directly wired to every other multisensory neuron. So how do they fire in concert? Objects have different features such as color, shape, sound, or smell. How does your brain figure out which features belong to the same object? How are unified conscious experiences bound in your brain? How does your brain connect the sight and sound of Marshall’s bun?
Called the binding problem, the question has many proposed solutions but no definitive answer to date. People might possess a single neuron for each possible combination of features, but that is unlikely given the sheer number of combinations. One solution, called feature integration theory, posits that binding is accomplished by an act of selective attention. It occurs within your spotlight of attention when your brain’s circuits combine different types of features of an object such as its color and brightness or shape and sound. The integration of two or more features speeds up the detection process and helps you to quickly adjust your attention to focus on the task you are performing. While neuroscientists have not settled on a solution to the binding problem, magicians merrily exploit the fact that attention-grabbing information from one sensory system leads to enhancement of attention in another. Thus a magician’s rapid-fire patter serves to increase how intently you stare at the actions he wants you to look at. The tapping of the saltshaker under the tabletop right before it appears to sink through the table forces your brain to pay attention and visualize the false event.
Next time you log on to the Internet, go to YouTube and type in “Terry Fator.” You won’t be disappointed. Fator won first prize in the 2007 America’s Got Talent competition with his ventriloquism act. His puppets impersonate famous singers—Roy Orbison, Elvis Presley, Marvin Gaye, and many more—while Fator’s lips never seem to move. The judges swooned. The audience screamed with delight. The Mirage Hotel in Las Vegas saw a good thing. Fator now has a five-year multimillion-dollar contract and his own theater to bring ventriloquism, an ossified art, into the twenty-first century.
Ventriloquism is the feat of shifting sound toward a visual target. It is a classic multisensory illusion with deep historical roots. In many preagricultural societies, shamans used ventriloquism to speak with the spirit world. Inuits would descend into a netherland full of growly voices and appear to use a harpoon in battle. They “emerged” covered in blood (thanks to a bladder of blood stashed under their parkas) to reveal truth and wisdom. In Greece, at the Temple of Apollo at Delphi, “belly speakers”—“ventriloquism” means “speaking from the stomach”—gave voice to divine revelations and prophecy emanating from the dead. When you think about the world before the invention of recorded sound, you can appreciate the wonderment elicited by ventriloquists. Today we are accustomed to sounds coming at us from all directions, in elevators, shopping malls, restaurants, and so forth. But before Victrolas and, much later, iPods, a voice coming from above the ceiling or from beneath the floor (a favorite ventriloquist trick) could be terrifying. It was black magic.
During the Enlightenment, ventriloquism lost its reputation as black magic when magicians stepped forward to demonstrate the art of “throwing one’s voice” and essentially demystified it. They described it for what it is: a multisensory illusion, one that takes an enormous amount of practice to make convincing.
Try saying “big love” without moving your lips. Or “mama papa.” When you look at Fator’s mouth, you’ll notice that his lips scarcely move. His throat moves, but he hides it behind a goatee and a microphone. Like all ventriloquists, Fator employs a set of acoustic approximations and articulatory tricks. Sounds made with the lips—p, b, and m—are acoustically similar to sounds made by the tongue on the soft palate—k, g, and (soft) ng. He can substitute the latter for the former. By forcing air through his slightly parted mouth, Fator can make the sounds f and v without using his lips. All other sounds in English can be made with duplications inside the mouth.
In the early twentieth century, ventriloquists such as Edgar Bergen (and his dummy partner Charlie McCarthy) were enormously popular. Bergen danced with his dummies, made silly jokes, and brought vivid characters like Mortimer Snerd to life. But when another source of multisensory illusion—talking pictures—arrived, ventriloquist acts like Bergen’s were doomed, displaced by the silver screen. For sheer entertainment there was no competition.
Next time you go to a movie theater, consider the fact that films are a form of ventriloquism in that speech is not coming from the actors’ lips. Sound is being piped into speakers far removed from their actions. Your brain creates the illusion of actors talking to one another, thanks to your multisensory brain. Moreover, images appear to be stable when in fact they are flickering. The steady appearance of a flickering light source—such as a fluorescent light, display screen, movie, or television set—is known as flicker fusion. It occurs when the rate of flicker is higher than a critical threshold, which for motion pictures is 24 frames per second.
Flicker fusion is thought to occur due to a process called persistence of vision. The concept was first presented to the Royal Society of London in 1824 by Peter Mark Roget (who also wrote the famous thesaurus) as the ability of your retina to retain an image of an object for between one-twentieth and one-fifth of a second after it is removed from your field of vision. Johnny Thompson exploited this fact in his red dress trick.
Max Wertheimer, the founder of the famous Gestalt school of psychology mentioned in chapter 2, and Hugo Munsterberg discovered a second principle—the phi phenomenon or stroboscopic effect, which is closely related to flicker fusion. You can perceptually bridge the temporal gap between two consecutive displays so that you perceive a series of static images in a continuous movement. Add this visual illusion to a nearby sound source and your brain does the rest: you are seamlessly transported to wondrous fictional worlds (unless of course you are watching a poorly dubbed foreign film!). The interconnection between our senses also plays a role in magic tricks involving memory, which is the subject of the next chapter. Consider this story.
As a reporter in the 1920s Soviet Union, Solomon Sherashevsky was able to remember names, dates, directions, sources, and other news-hound essentials—without ever writing anything down. His editor thought Sherashevsky was being lazy in staff meetings, since he didn’t take notes of his assignments, and one day he asked the reporter to repeat every word of what had been said at that morning’s briefing. Sherashevsky did so, flawlessly—somewhat amazed, we are told, that his talent was considered unusual. The dumbstruck editor sent Sherashevsky to the laboratory of Russian psychologist Aleksandr Romanovich Luria “to have some studies done on his memory.” In the years that followed, Luria studied “the man with the vast memory,” noting that his talent stemmed from a form of synesthesia. Sherashevsky saw vivid images—such as splashes of color or puffs of smoke—with every word, number, and syllable. Whenever he wanted to recall numbers, syllables, words, or events, he would conjure up the combinations of images in his mind’s eye and report what he saw. In this way, he could remember almost everything he encountered. As we’ve seen, magicians, even if they don’t have synesthesia, can capitalize on the mingling of the senses.
