The Null Device
Stage magician Teller explains some of the cognitive principles behind the magician's craft:
1. Exploit pattern recognition. I magically produce four silver dollars, one at a time, with the back of my hand toward you. Then I allow you to see the palm of my hand empty before a fifth coin appears. As Homo sapiens, you grasp the pattern, and take away the impression that I produced all five coins from a hand whose palm was empty.
2. Make the secret a lot more trouble than the trick seems worth. You will be fooled by a trick if it involves more time, money and practice than you (or any other sane onlooker) would be willing to invest. My partner, Penn, and I once produced 500 live cockroaches from a top hat on the desk of talk-show host David Letterman. To prepare this took weeks. We hired an entomologist who provided slow-moving, camera-friendly cockroaches (the kind from under your stove don’t hang around for close-ups) and taught us to pick the bugs up without screaming like preadolescent girls. Then we built a secret compartment out of foam-core (one of the few materials cockroaches can’t cling to) and worked out a devious routine for sneaking the compartment into the hat. More trouble than the trick was worth? To you, probably. But not to magicians.
3. It’s hard to think critically if you’re laughing. We often follow a secret move immediately with a joke. A viewer has only so much attention to give, and if he’s laughing, his mind is too busy with the joke to backtrack rationally.
With the recent Royal Wedding and the upcoming Olympics, London's public transport authority has declared war on underground explorers, whose activities have now become a matter of national security:
"Normally we would have been dished off to the graffiti squad," Otter says. "But because of the wedding we ended up with detectives much higher up."
Last month TfL applied to issue anti-social behaviour orders which would not only stop them undertaking further expeditions and blogging about urban exploration but also prohibit them from carrying equipment that could be used for exploring after dark. Extraordinarily, it also stipulates they should not be allowed to speak to each other for the duration of the order – 10 years.