The science of magic tricks

A magician must make a trick look effortless, but there is very little that is casual or spontaneous in a magic show. If you are lucky enough to watch a performance by a sleight-of-hand master such as Teller (of the magic duo Penn & Teller), Johnny Thompson or Juan Tamariz, chances are that nothing has been left to chance. Though other artistic fields also make performances look easy, magic is on a different plane.

Think of it this way: if you go and see George Balanchine’s The Nutcracker by the New York City Ballet, you will have no trouble imagining all the sweat and tears that must have gone into achieving those amazing dance moves. Your body can’t do that, and you know it. Magic is just as choreographed, of course, but the nature of the art is that it must not look so. The motions of the hands and body must look like the ones you naturally make every day. Yet, even a causal drop of the magician’s shoulders – which the audience will hopefully not notice or remember after the show – can be filled with purpose and intent. That shoulder drop might have been the weapon of magical murder.

Magicians master sleight of hand to deceive the audience

Magicians master sleight of hand to deceive the audience

Artists of all kinds, including magicians, are connoisseurs of human behaviour and perception, and strive to evoke particular experiences in their audience. Magicians can alter a spectator’s perception in a variety of ways, but their speciality is attention management – known as misdirection. The concept of misdirection is often misunderstood. Audiences may believe that the magician distracts their attention during a critical move or manipulation, but this is not correct. They do not strive to turn spectators’ attention away from the ‘method’ – the secret behind the magic trick – but instead aim to direct their attention towards the magical effect. This is a critical point, and the reason it works is grounded in neuroscientific findings about the way our attention is controlled – a bit like a spotlight – by the brain.

The spotlight of attention is a metaphor used by neuroscientists and magicians alike and refers to the fact that we aim our attentional focus like a flashlight. Whatever object, person, or action we concentrate on appears more salient and even brighter than the rest of the scene. However, the neuroscience informs us that there is one fundamental difference between your attentional spotlight and your iPhone’s torch app. The reason things become more noticeable when you attend to them is not that your neural circuits boost your perception to make you more focused, but that everything else is actively suppressed. In other words, the spotlight of attention only seems to shine by comparison to the surrounding darkness. This means that magicians need only ensure that audiences aim their attention to specific spatial locations on the stage, and each spectator’s brain will take care of suppressing everything else – including the secret method hiding behind the magical effect. In a very real sense, your brain is the magician’s assistant.

Research suggests that these enhancement and suppression processes are mediated by two different populations of neurons in the visual cortex – the area at the back of the brain that processes visual information. How do magicians, then, drive the audience’s attention to particular places and time intervals during a performance? One effective way to misdirect somebody’s attention is by changing where they are looking. Magicians employ various strategies to control your eye position. These include asking specific questions about particular items on stage (“Tell me what card this is,” or “What is the year on this coin?”) and using their own body language and gaze direction to induce joint attention behaviours in the audience.

Joint attention is the mechanism that makes us gaze at something when we see other people doing it. For example, if you see a crowd of people looking up in the street, you will find it irresistible to look up as well. If the magician wants the audience to look at a specific object, he himself will pretend to be completely absorbed by it. However, if the magician wants the audience to look at his face, he will direct his own gaze to the rows of seats – even if he cannot actually see the audience due to the stage lighting – and the spectators will reciprocate.

Yet magicians can be subtler than just misdirecting your gaze. They do not necessarily have to change the audience’s direction of gaze in order to shift their attentional focus. When they succeed, audiences are looking at the right place, though without seeing, because their attention is engaged elsewhere. It’s powerful magic indeed. One way to mess with somebody’s attention, without diverting their gaze at all, is to split their focus. The same attentional neural mechanisms that boost our perception (at the centre of the spotlight) and suppression (in the surrounding areas) make it very difficult for us to multitask. We have a single attentional focus, which cannot be divided without losing effectiveness.


Magicians carefully plan their movements to direct the audience’s attention away from their manipulation

Magicians get audiences to multitask in a variety of ways. One such strategy is the very design of certain magic tricks. One prime example is the ‘cups and balls’ trick, one of the oldest magic tricks known – there are even records of performances taking place in Ancient Rome! It is usually performed with three cups placed upside down on a table. Balls and other objects magically appear and disappear inside the cups, much to the audience’s amazement. The way the performance is arranged forces spectators to split their attention between a minimum of three places on the table (the inverted cups), making their focus at most a third as precise as it might have been had they attended to a single location. The tactic is to divide the audience’s attention and conquer their perception of what is happening. 

Another way to make spectators try to multitask is to engage their senses and their mind in multiple ways simultaneously. Apollo Robbins, a world-renowned theatrical pickpocket, uses sight, sound (patter) and touch (tapping various parts of a volunteer’s body onstage) to misdirect attention away from the pocket or wrist that he intends to steal from. Many other magicians also use rapid fire ‘patter’ to overwhelm the audience’s auditory and language processing capabilities. So when Penn is talking a million words a minute on stage, what he’s actually doing is bombarding you with information to keep your brain busy.

One main goal is to create ‘internal dialogue’ in each spectator: if audience members are having even a simple inner discussion with themselves, they won’t be focusing as much on what’s going on right in front of their eyes. The Spanish magic theorist Arturo de Ascanio advised magicians to “ask a discombobulating question”. Even by asking: “Has anybody brought a scarf?” will get each spectator to ponder the question for a second or two. During that brief interval, they are trapped within their heads and unable to process other inputs efficiently; the magician is free to perform the secret move. 

Emotion is also used to the magician’s advantage, as feelings and attention are pretty incompatible. This is one main reason why eyewitness reports are famously unreliable. If you find yourself in the situation of having to give testimony in court or file a police report about something you witnessed, it’s highly likely that the event in question led you to experience a strong emotion. Human memory is certainly limited, and more so when you are scared. Some magic performances contain horror or gory elements – one of Teller’s signature tricks is to ‘drop’ a cute rabbit into a wood chipper – but humour is the emotion that magicians choose to provoke most often. Hilarity in a magic show increases the entertainment value and hampers the spectators’ ability to concentrate. Johnny Thompson (also known as The Great Tomsoni) says that while the audience laughs, time stops. It’s during this interval that the magician is safe to make a move, perhaps in preparation for the next trick.

magic trick 1Magic trick 2

How is it that magicians have arrived to such a refined understanding of human nature? One answer is that, whereas the field of cognitive neuroscience – the study of mental processes – is only a few decades old, the magical arts have been around for a very long time. Magicians have had millennia to figure out what works and what doesn’t. Spanish magician Miguel Angel Gea says that each performance is an experiment; every trick puts a hypothesis to the test. Even without applying the scientific method in any rigorous fashion, it makes sense that magicians must have figured out a thing or two about cognition and perception. Even if they have no better methods than trial-and-error, they are smart people doing serious analyses of the human condition; they will eventually discover a few important facts.

It is only recently that the neuroscientific community has come to appreciate how magic can conjure new insights into the human brain. In 2008, we coined the word ‘neuromagic’ and today, more than a dozen laboratories around the globe have conducted studies on the neural bases of magic performances. Whereas not all magic theories have panned out in the lab, it has also become apparent that cognitive neuroscience, as a discipline, has reinvented the wheel sometimes – arriving to conclusions that magicians had held true for quite a while. It may be that these amateur brain hackers still have some tricks up their sleeves that can help advance neuroscientific discovery. 


Article extract from “The Science of Magic Tricks” by Susana Martinez-Conde and Stephen L Macknik in How It Works issue 82, available now from the Imagine Shop


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