Magicians are way ahead of psychologists when it comes to understanding and exploiting the human mind and our perceptual quirks.
A new study, detailed in the current online issue of the journal Trends in Cognitive Sciences, reveals how elements of human cognition, such as awareness and perception, could be explained by the success of some techniques commonly used by magicians.
For instance, vanishing tricks rely on the idea that we are only aware of a small part of what's in our visual field.
"Although a few attempts have been made in the past to draw links between magic and human cognition, the knowledge obtained by magicians has been largely ignored by modern psychology," said researcher Ronald Rensink, who specializes in vision and cognition at the University of British Columbia in Vancouver.
Seeing is believing?
Rensink, UBC colleague Alym Amlani and Gustav Kuhn of Durham University in England recently lifted the lid on some key techniques in the classic magician's toolbox.
One of their revealing experiments highlighted the disconnect between what participants saw with their eyes and what they were focused on with their minds.
The researchers showed 46 participants a video clip of a magical performance while measuring each subject's eye movements. In the performance, a cigarette and lighter once in the magician's hands disappear (he drops each into his lap). About 50 percent of the participants claimed to see the objects being dropped while the others didn't.
"What people actually saw was not related to where they were looking," Kuhn told LiveScience. "Several participants who were looking at the object being dropped failed to see how it was done."
Even though their eyes were focused on the objects, their attention was elsewhere, he said.
Magicians have used so-called misdirection tricks for centuries to make scarves or animals appear out of thin air or cause other objects to vanish. But it's only been in the last two decades that vision scientists have found that only a small part of the information that enters your eyes, essentially the part that has grabbed your attention, enters your conscious awareness.
More mental tricks
Optical illusions rely on the fact that we can "see into the future." When we see a magic trick, for instance, the light from the objects hits our retinas about one-tenth of a second before the brain translates the signal into a visual perception. To compensate for the neural lag, we have evolved to predict the outcome of events.
These predictions leave us vulnerable to deception, the researchers say.
For example, a vanishing ball illusion indicates that anticipation plays a factor in what we see, and our minds fill in the blanks. In this trick, the magician tosses a red ball into the air two times and on the third throw, instead of releasing the ball, the magician holds onto it. However, study participants reported seeing the magician toss the ball into the air three times before the ball "disappears."
Then there's the trick where you pick a card from a deck of playing cards. Voila, a magician guesses which card you picked. Turns out, this "magic" is really a mind trick called forcing where the magician controls which card you pick by, say, putting you under stress to act quickly.
A study led by Petter Johansson of Lund University in Sweden published in the journal Science in 2005 showed that observers often fill in the gaps of memory by fabricating reasons for their choices.
The researchers say magician's techniques could be used by cognitive scientists to test various theories.
"Magicians have been using these psychological principles to manipulate our perception [for centuries]," Kuhn said. "Cognitive science, particularly looking at attention and the interaction between attention and awareness, is a fairly new discipline, whereas magicians have been doing this for centuries."