When Gustav Kuhn was 13, a friend pulled an egg out of his ear.
Kuhn was astounded – but his wonder didn’t abate, even after he learned that the egg was made of foam and had been easily hidden in his friend’s hand.
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“I was quite fascinated by those eggs,” he recalls. The trick sparked an obsession with how the brain can be hoodwinked into believing the impossible. “My whole life during my teenage years was centred [on] magic and deception,” he says. “I became completely addicted.”
Kuhn’s adolescent fascination eventually led to a career in magic – although he hasn’t exactly followed the trajectory he had in mind at 13. Though he is a practising magician, he is primarily a psychologist, working to understand what the cognitive quirks that lead us to perceive a rabbit being pulled from a hat or a levitating £5 note can reveal about the brain. “I’ve been trying to create the science of magic, which uses [tricks] as a way of exploring the human mind,” says.
It seems to be working – more than have been published since the late 2000s. This research attempts to peel back the layers of conscious experience to demonstrate how expectation seems to control our perception of reality and how easily we can be led into making decisions while retaining a sense of agency.
The field, though, has attracted criticism from members of both disciplines. Some scientists worry that it lacks rigour, while some magicians are concerned that these experiments strip the mystery from their tricks. Is the science of magic itself just a beautiful illusion – or can it reveal something profound about how our minds work?
The psychology of prestidigitation
The inclination to bring magic and science together has a strong historical precedent. Alfred Binet, a ھ--è psychologist who invented the first intelligence test, was particularly prestidigitation, or sleight of hand. Binet suspected that they created their illusions by shifting their fingers too fast for the eye to perceive. To capture their movements, he turned to a new technique, chronophotography, a precursor to film cinematography that took successive images of a subject in motion, at a rate of .
In his resulting 1894 paper, , Binet reported that the illusions disappeared when observers watched the slowed-down, silent clips. Without the performer’s speed, patter and showmanship, there was no magic. Binet concluded that the tricks relied on mental processes like attention, noting, “Prestidigitation rests on psychology.”
Like magic
But such observations would be more or less ignored by psychologists for a century – a source of frustration to Kuhn as he embarked on his career. In 2008, he co-wrote for the influential journal Trends in Cognitive Sciences, urging other psychologists to find inspiration in magicians’ illusions. “Although a few attempts were made in the distant past to draw links between magic and human cognition, this knowledge has been largely neglected by modern psychology,” argued Kuhn and his co-authors. “We propose that the time has come to examine these phenomena more closely, and to connect them to current theories and methodologies for exploring the human mind.”
So Kuhn and other like-minded scientists did exactly this, starting with the same kinds of illusions that Binet examined. A classic deception known as the “vanishing ball illusion” – already well-known when Binet discussed it in 1894 – provides an ideal example. In this trick, a magician repeatedly tosses and catches a ball. At one point, they make the same movement, but, having concealed the ball in a pocket or with their hands, they don’t throw it. Quite remarkably, most spectators report seeing the ball fly up into the air before it vanishes into nothing.
The effect can be startling. “It produces a distinct feeling that’s more than just basic surprise,” says , a psychology researcher at the University of Essex, UK. “It really does look like it’s disappeared.”
The illusion is thought to work because of “predictive processing”, a theory of consciousness that is gaining ground among cognitive neuroscientists, psychologists and others. This framework suggests that the brain is constantly making predictions about the world around us to inform complex simulations that help it make sense of the imperfect data gathered by our sensory organs. Our experience of reality is dictated by these mental models. Most of the time, they match what is occurring in the real world – but they can sometimes make incorrect predictions, producing a sense of something that isn’t there. In this case, the expectation that the ball will rise out of the magician’s hand creates a split-second impression that it is rising in front of us. When the data from our eyes catches up with the brain’s simulations and corrects them, the perception of the ball vanishes while it is in mid-air.
“We don’t have a picture of the world as it is,” says , a cognitive psychologist at the Marie and Louis Pasteur University in Besançon, France. “We add a little bit of anticipation.”
Tricks like the vanishing ball illusion demonstrate just how easy it is to prime the brain’s simulations. Kuhn, for instance, found that around a third of people will , for instance, without any of the usual ball-tossing beforehand.
A glitch in reality
One theory had been that social cues drive the participants’ expectations. In the classic vanishing ball illusion, the magician raises their eyes as if they are following its trajectory, which was thought to help prime the illusion. Thomas, however, has since shown that it works just as well if the performer’s face . “Their gaze is not the main factor here,” he says.
The “phantom vanish magic trick” shows that it is even possible to create the , which then disappears mid-performance. This illusion, which tests the limits of our brain’s predictive models, is the invention of , a cognitive science researcher at Lund University in Sweden. In a video, Tompkins pantomimes taking an object out of a cup and placing it in a closed fist. He then clicks the fingers of the other hand and opens his fist to reveal a clean palm. Of the 420 participants, 136 – or about 32 per cent – reported having a visual impression of the phantom object. For some, it was a fleeting experience that was difficult to describe, but others went as far as to note its non-existent shape and colour.
Their minds may have constructed some of these details after the event, or the participants may have actually “seen” them in a kind of controlled hallucination. Either way, this demonstrates the brain’s ability to fill in small gaps in its perception, which could be useful in day-to-day life to form a coherent view of reality, like adding a missing word to a sentence whose entirety you didn’t quite catch. “Magic is exploiting otherwise adaptive processes,” says Tompkins.
Sceptics might suggest that the participants weren’t being totally honest or that they had simply reported seeing something magical because they knew that is what the researchers expected them to see. This didn’t appear to be the case, however. When they watched a control video of Tompkins elaborately placing a coin in his mouth, they were distinctly unimpressed. Their reports of the phantom vanish magic trick appear to have been genuine, reflecting a momentary glitch in the brain’s elaborate constructions of the world around it. Such errors may happen all the time without us even noticing them.
It seems that many of our everyday experiences may need a reality check – and that could extend to the times we believe we are exercising free will. Consider a basic card trick, in which a participant is asked to pick from a selection of cards in front of them. The magician wows the audience by naming the suit and number before the card is even turned over. In such cases, the magician will have applied a “forcing” technique to ensure that their mark picked a pre-determined card. The choice looks random to everyone except the performer, who has been dictating the selection all along.
Pick a card, any card
Some forcing techniques rely on the inherent predictability of our behaviour. Imagine, for instance, that a magician lays four cards in front of you. Which would you select? If your choice was totally random, there would be a 25 per cent chance of choosing each one – but Kuhn and his colleagues have found that around opt for the third from the left, since it is the easiest to reach.
Most stage magicians would rely on more sophisticated manipulation. Illusionist Derren Brown, for instance, became famous for his ability to plant the idea of a particular card in participants’ minds. To examine this scientifically, Kuhn’s colleague recorded a video with the following script. “I’m going to try to transmit to you the identity of this card,” she says, while holding up a card with its back facing the camera. “Imagine a screen in your mind, and on this screen, the little numbers low at the bottom of the card, in the corners, and at the top, and then the things in the middle, in the centre of the card… and in the middle of the card.” The viewer then writes down what was in their mind.
The words give very little away. Pailhès’s presentation, however, incorporates some non-verbal signals that are designed to lead the person watching towards picking the three of diamonds. While asking them to picture a screen, for instance, she makes a diamond sign with her fingers; she also draws the figure 3 in the air while describing the numbers on the card.
If you are sceptical that such tiny gestures could influence anyone’s behaviour, you aren’t alone: “I was convinced it wouldn’t work,” says Kuhn. He was happily proved wrong. The probability of selecting the three of diamonds at random is 1 in 52, or 1.9 per cent, but around – 17.8 per cent of the participants – chose the card. Even if they didn’t get the exact combination, they were considerably more likely than chance to pick either the correct suit (33.3 per cent) or the correct number (38.9 per cent). “Unconscious priming is super rare, and the effects are generally quite small,” says Kuhn. “So I was very surprised by how reliable that effect was.”
The illusion of free will
Crucially, the participants had , believing their choices were entirely theirs. Kuhn describes this as an “illusion of agency”, and it is most powerfully demonstrated with the “equivoque forcing technique”. Once again, the participant is given four potential cards, face down. They are first asked to narrow the choice by touching two cards, after which a pair is removed from the table. They repeat the same process, selecting one of the two cards, one of which is removed. The magician will then turn over the remaining card to reveal that it is the one that they had predicted.
If this description sounds vague, that is deliberate. Rather than asking them to “pick” or “choose” the cards, the magician asks the volunteer to “touch” them in each round. Without explicitly explaining whether the selected cards will be left or discarded, the magician can proceed however they want. If the volunteer touches the cards the magician wants, they keep them on the table; if not, they discard them. In this way, the magician can ensure that the desired card is the last one remaining.
Magic is exploiting otherwise adaptive brain processes
The ruse seems obvious when it is spelled out in this way. Yet Kuhn and Pailhès have found that that they had some control over the card they chose. “They are not aware that their decisions have no impact on the outcome,” says Kuhn. The illusion of agency appears to be so strong that it remains after an immediate repetition of the trick. Despite going through the same procedure a second time, the participants are still none the wiser about the trick’s mechanisms.
Such replicable findings have helped to move the science of magic out of its infancy and into adolescence. It is also important to note that many of these experiments necessarily lack some of the showmanship of stage tricks. Though this has occasionally raised the eyebrows of professional performers, it is in aid of the “science” part of the science of magic. “We have to reduce a lot of variables so you can work out the contribution of a specific method,” says Tompkins.
But the development of the science of magic has been accompanied by some growing pains. Cole, for instance, is concerned about the rigours of the field. He argues that some papers have failed to apply some of the basic principles of good research, such as controlling for confounding factors. “It’s gone too much towards the magic paradigm,” he says. at the University of Hertfordshire in the UK, meanwhile, questions the originality of the recent research, including some of the perceptual illusions. “They’re very neat applications of things that psychologists already know about, but I’m not certain they’re bringing very much new to the party, though they are very good for teaching.”
The magic of aha! moments
Kuhn readily admits that the quality of the research varies – as it does in other fields – but notes that the science of magic is already inspiring novel approaches in seemingly unrelated fields. primary interest, for instance, is in problem-solving, particularly those when inspiration strikes. Experiments in this field often use anagrams and geometrical puzzles, but Danek, a theoretical psychologist at Heidelberg University in Germany, has found that asking people to solve magic tricks tends to produce better results. “They’re a very strong stimulus,” she says. “People really want to know how they are done.”
Her work shows that the strong sense of reward that accompanies the moment of insight brings a major memory boost – a finding with immediate implications for education. “Ideally, we would have teachers setting the stage so pupils can have their own aha moments,” she says.
Kuhn is expanding on these findings. “We’re combining magic tricks with neuroimaging to give the illusion that we can insert thoughts and looking at the impact that that can have on people’s creativity,” he explains.
That is just one of many projects exploring the possibilities of the science of magic. Another will explore the parallels between magicians’ tricks and those used by fraudsters. “I think there is a lot of scope to use magic as a way of enhancing critical thinking and raising awareness of the deception that happens in our everyday lives,” says Kuhn.
Twenty-five years into his career, Kuhn isn’t as fascinated by foam eggs as he once was. But he has lost none of his enthusiasm for magic and for most people, he says, knowing how the trick is done – understanding the psychological explanations of the phenomena – doesn’t ruin the enchantment. In fact, it only inspires greater awe and wonder: “I love magic, and I strongly believe that we are only enhancing the art.”
