[6 February 2012]
Until the invention of the MRI machine, which allowed scientists to monitor neurological behavior on a second-by-second basis, psychologists treated the brain like a black box, using lab experiments and field research to deduce the cognitive principles behind human reasoning. But, as Stephen L. Macknick and Susana Martinez-Conde, a married pair of neuroscientists, write in Sleights of Mind: What the Neuroscience of Magic Reveals About Our Everyday Deceptions, in many ways, the best psychological experiments occur outside of the lab.
Dismissing magicians who claim paranormal power as charlatans, they see magic tricks as “testing many of the same cognitive processes [the authors] study. It doesn’t matter in the slightest that the entire audience knows it is being tricked; it falls for each trick every time it is performed, show after show, night after night, generation after generation. We thought, if only we could be that deft and clever in the lab!”
The book attempts to bring the two seemingly disparate worlds together, exploring what the practice of magic can teach us about the brain while delving into the science behind many of magic’s greatest illusions.The authors, who co-wrote the book with New York Times science writer Sandra Blakeslee, are unabashed magic fans. The book begins with some of the today’s most famous magicians—the Amazing Randi, the Great Tomsini, Penn & Teller—beguiling their colleagues at a neuroscience convention and ends with their audition at the Magic Castle in Hollywood, where they perform their own brand of scientifically-influenced magic.
It’s a somewhat clumsy attempt to shoe-horn a narrative on top of what is essentially a psychology class for non-majors textbook. Over 12 chapters, the authors use scientific principles like “change blindness” and “the misinformation effect” to explain how magic tricks work even when we know what the magicians are doing.
Sleights of Mind isn’t the type of book that demands a reader tear through it front to back. It’s more informative than entertaining, full of little stories and slices of life that can change your perspective on everyday situations.
The underlying principle behind most successful magic is what neuroscientists call “the narrative bias”: the fact that our brains unconsciously search for explanations for what’s going on in the world. Because our capacity for attention is narrow, the brain relies on past experience to make assumptions about the world around us. That’s how movie projectors work: seeing hundreds of images flash by every second creates the illusion of motion, with the brain filling in the blanks.
In a famous experiment on attention, volunteers were asked to count the number of passes made by one basketball team during a game. After a few minutes, the video was stopped and they were asked if anything out of the ordinary happened. Half the people who watched the video didn’t notice the man in the gorilla suit who walked to the middle of the court, stared at the camera and pounded his chest.
Even more intriguingly, when scientists used eye-tracking recordings on the volunteers, they found that most of the people who didn’t notice the gorilla in the video looked directly at it. Because they were so focused on the task they were “assigned”, and because a mascot walking on to the court is so out of the ordinary, their brains ignored what their eyes saw.
Similarly, if you see a coin in a magician’s hand, see him open his hand as if he were dropping it into a bucket and then hear the sound of a coin hitting the bucket, your visual attention system is going to connect the dots for you. You will “see” the coin fall into the bucket even if it has never actually left the magician’s hand.
No matter how realistic they may make it seem, magicians can’t make things disappear or conjure objects out of thin air. Instead, they take advantage of the magician inside of all us—the brain.