Why can't you spot what a magician is doing right in front of you?

Most magic tricks do not work because your eyes fail. They work because your attention is somewhere else. The technique is called misdirection: in theatrical magic, the performer draws the audience's attention to one thing to distract it from another. The writer Henry Hay called the central act of conjuring a manipulation of interest, and the Encyclopedia of Magic and Magicians calls misdirection the cornerstone of nearly all successful magic. Without it, even the most skilled sleight of hand or mechanical device is unlikely to create an illusion of real magic.

Magicians steer attention in two basic ways. In the first, they lead the audience to look away for a fleeting moment, so that nobody detects a move. In the second, they re-frame what seems to matter, so that people credit some extraneous factor with the feat when it has no bearing on the effect at all.

Scientists have tested this with a real trick. In studies of a vanishing-item trick, people watched it once and then were shown it again until they spotted the item dropping from the magician's hand. Most people saw the drop on the second viewing. The event was easy to see once attention was on it; the first time through, attention was simply elsewhere.

The idea also reaches well beyond the stage. An early reference comes from the performer and writer Nevil Maskelyne, who wrote of misleading the spectator's senses to screen details that require secrecy, and in World War II British military intelligence employed the stage magician Jasper Maskelyne to help devise ruses, deception and camouflage.