Sleights of Mind

by Stephen Macknik and Susana Martinez-Conde with Sandra Blakeslee

Stephen Macknik and Susana Martinez-Conde are scientists who have applied their study of the brain to the art of magic, and vice versa, and asked what magicians have to teach neuroscientists. In many ways it's amazing that this kind of study hasn't been undertaken more extensively already. To read Sleights of Mind you might suppose that all magic tricks are tricks of the mind in some way.

The book begins with an analysis of visual illusions, which often rely on the gaps in the way we process what we see. The discussion touches on focus and peripheral vision, depth perception, saccades, the way we track moving objects, how our eyes compensate for changes in contrast, and more. It's all presented amidst lots of entertaining anecdotes and examples of magical performances. You learn a great deal without realising it. The authors seem to have a real knack for teaching science without making it look as though they're teaching at all.

Throughout the book there are alerts marking the sections which explain how the magic tricks are done. In theory this is so you can skip the parts that might be considered spoilers, and continue to enjoy magic shows as a complete layperson. In practice I don't see why anyone would want to avoid these explanations. They're very interesting, and if you pay attention to the scientific details it's sometimes possible to figure out how they're applied in tricks anyway. The spoilers make up a fair portion of the book. This is definitely a volume that lays magicians' secrets bare.

The book deals with attention and misdirection, which is one of the main items in the magician's toolkit. Certain neurological problems tell us more about the way the mind works. People with autism, for instance, have difficulties with joint attention, which is when you pay attention to whatever someone else is looking at. This makes some people with autism harder to trick with magic.

The wide-ranging discussion takes in recent research into various aspects of neuroscience including memory, vision, and child development studies. It's hard to read this book without getting a sense that you're walking around in a fog of sensory confusion most of the time. Objectively we know our minds aren't perfect. What the authors do is reinforce just how imperfect they are in so many different ways. We're subject to change blindness, false memories, multisensory illusions, choice blindness, priming with suggestions, placebos, and all sorts of irrational beliefs. We can be made to think we came up with an idea on our own which was in fact implanted by someone else.

Depressingly, our brains are designed to think as little as possible. In Chapter 8 the authors explain that "... thinking is expensive. It requires brain activity, which takes energy, and energy is a limited resource." This quote is about habituation, which is when we don't question our unspoken assumptions about everyday things we see habitually. But our brains tend to take shortcuts in most areas, which makes grey matter both highly efficient and easy to manipulate if you know what it's missing out.

Magicians make willing fools of us all for entertainment, but they're not the only ones willing to exploit the way our minds work. Advertisers, salespeople, charlatans, pickpockets and con men are all using the techniques described in this book. This is knowledge you don't want used against you, so in that sense the book is essential reading. There's also a handy list at the end of the ways you can apply the things magicians know to improve your own life.

In terms of readability Sleights of Mind is both easy to understand and very engaging. When the authors describe the time they tried out for the Academy of Magical Arts they really get readers rooting for them. Yet they also succeed in cramming a lot of science into this book amongst all the funny and very human anecdotes, and like accomplished magicians they make it look easy.