About Rationally Speaking

Rationally Speaking is a blog maintained by Prof. Massimo Pigliucci, a philosopher at the City University of New York. The blog reflects the Enlightenment figure Marquis de Condorcet's idea of what a public intellectual (yes, we know, that's such a bad word) ought to be: someone who devotes himself to "the tracking down of prejudices in the hiding places where priests, the schools, the government, and all long-established institutions had gathered and protected them." You're welcome. Please notice that the contents of this blog can be reprinted under the standard Creative Commons license.

Tuesday, August 30, 2011

Magically Thinking

by Lena Groeger

Magic. In the realm of the rational (or at least at a blog called Rationally Speaking), magic is usually something to be debunked, explained, or exposed as the normal quite of-this-earth phenomenon that it really is. Magic, and those who claim to perform it, present more obstacles than insights to the people who want to understand things as they really are.

Except — magic might teach us more than we think.

In a recent book called Sleights of Mind, neuroscientists Stephen Macknik and Susana Martinez-Conde take a closer look at magic — from the perspective of the brain. “Pop[ping] the hood on your brain as you are suckered in by sleights of hand,” is how they describe their magical adventure into visual illusions, attention misdirection, change blindness, multisensory perceptions and all sorts of other cognitive tricks that magicians perform daily, but scientists are only just beginning to understand.

Coining the term “neuromagic,” to describe their new field, the authors explain how “magic tricks work because humans have a hardwired process of attention and awareness that is hackable.” Understanding how magicians manipulate our brains into thinking the impossible can tell us how our brains might be “hacked” in other situations (and why they evolved to be hackable in the first place). Magic, the authors claim, reveals just how much deception is “part and parcel of being human.”

What follows are just a few of the many stops on these fascinating parallel tours through magic and the brain. I’ve chosen to focus on one of the obvious cognitive hacks integral to any magic trick: attention.

Magicians take full advantage of attention — guiding it, focusing it, and yes, misdirecting it. Macknik and Martinez describe multiple ways in which magicians are able to exploit the when and where of what others have dubbed the “spotlight of attention.” In an overt manner, a magician may ask you to read a passage of a book or focus very hard on a particular image — while he steals your watch. Alternatively, bright lights, smoke and mirrors, the fluttering wings of a white dove are all used to overload your sensory system with stimuli, and thus distract you from the real trickery going on in front of your eyes.

But not all attention misdirection is so blatant. In fact, in many cases you can be looking right at the object in question — the coin that disappears, the handkerchief that materializes out of thin air — and still not notice anything. You remain entirely oblivious to the method of the trick because you are directing all your attention elsewhere. As the neuroscientists put it, “you look, but you do not see.”

In scientific speak, this phenomenon is called “inattentional blindness.” For a famously entertaining illustration of how it’s possible to be staring right at something you cannot see, check out this video. Once you’ve watched it, read on.

Why is it so hard to spot the gorilla? For a long time scientists thought it was because people were simply not looking directly at the ape; their eyes were just following the basketball players. However, subsequent eye-tracking studies revealed that in fact, the people who failed to see the gorilla had been staring right at it — and for just as long as the people who did notice. Instead of the direction of their gaze, it was the intense focus on counting passes that stole their attention away, and rendered the gorilla invisible. Macknik and Martinez describe how “visual perception is more than photons entering your eyes and activating your brain. To truly see, you must pay attention.”

A similar phenomenon is called “change blindness,” and refers to how well (or badly) your mind can remember what it has just seen. Ever had to spot ten differences between two photographs? Even after going back and forth multiple times between the two images, it’s hard to catch all ten. So it’s no wonder that we often completely miss dramatic changes in our environment — our brain is superbly good at filling in the gaps. As this video makes clear, when we are even slightly distracted we can miss some pretty obvious changes. (Like, say, the race and gender of a person asking for directions. Seriously.)

Magicians have some other tricks to manipulate attention, like emotion. While the relationship between humor and attention hasn’t been studied in detail, neuroscientists think that laughter generally suppresses attention. You’re less likely to notice a flaw or mistake when you’re rolling in your seat, or even politely chuckling to a somewhat lame joke.

Your attention may also depend on something as simple as the difference between a straight line and a circle. In their collaboration with magicians, Macknik and Martinez learned that when a pickpocket wants to distract someone from what he is doing with one hand, he will move his other hand in an arc. If he wants to direct someone’s attention to the end point of a gesture, he will move his hand in a straight line. It may be the case that our eye movements (and our attention) differ during those two scenarios. An arc is unpredictable, so we focus our attention on following his hand — and don’t notice our wallet being removed. A straight line has an end point, so we jump to the final destination and don’t worry about what happens on the way.
Scientists already know that our eyes move differently when we are sweeping our gaze across the room or tracking a moving object. In the first case, our eyes make tiny jumpy movements, called saccades. In the second case, our eyes move smoothly along the path of the object we are following. Could the differences in saccadic or smooth eye movements also affect our attention? Macknik and Martinez are interested in studying this possibility — just one of the many ways a magician’s insight can spur new directions in neuroscience research.

There are many other examples throughout the book (or lurking on YouTube) that demonstrate the cognitive quirks we live with every day — and that make “magic” possible. Who knew the inner workings of magic tricks would teach us so much about the inner workings of the mind.


  1. Lena

    Re: 'Why is it so hard to spot the gorilla?'

    Because there was no gorilla- at least, not in the video to which you linked. It was a moonwalking bear. Are you instead referring to a passage discussed in 'Sleights of Mind'?

  2. Eamon, you're right. I corrected the link (it illustrates the same idea.) Thanks!

  3. Very interesting. Thanks for the book tip. I really did not see the gorilla at first pass. (Just for fun, here's a magician who really has appropriated himself a cornucopia of distractions. Piff the Magic Dragon on Penn & Teller: http://www.youtube.com/watch?v=kk5xfK0ovrk ).

  4. Great article!

    I used to have a trick in high school; I've lost the knack of it now. Basically, if you spot a friend with something in their hand (say, an mp3 player), you engage them in conversation, and then take the item from them as if they had intended to give it to you, while never halting the conversation. It has to be completely natural, as though this were something the two of you had already agreed to do & you had just remembered.

    Then, of course, you return it, at which point your friend tries to figure out why they gave you their mp3 player in the first place. Levity ensues.


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