One day, while he was messing around with an empty water glass and a wadded-up paper napkin as a ball, Teller devised a new variation on the trick using transparent cups. The idea being that, even though audiences could see the balls being moved around, the magician's sleight-of-hand misdirected the attention so much that the mind was still fooled.
In fact, Teller even tricked himself. During one manipulation, he turned a glass upside down and put a napkin ball on top. Then he tilted the glass so that the ball fell into his other hand. As it fell, the ball's trajectory was so compelling that it drew his attention away from his original hand, which was loading a second ball under the glass.
He figured if he could fool himself, then he could surely fool an audience, and thus the transparent "Cups and Balls" trick was born.
"Teller thought there was something particularly compelling about the drop of the ball -- that falling objects and gravity have a special place in how our attention is captured," said Dr. Susana Martinez-Conde, director of the Laboratory of Visual Neuroscience at BNI and co-author of the study.
So Macknik and Martinez-Conde -- their own duo of sorts, as in husband and wife -- set out to investigate Teller's hypothesis that the falling ball generated a stronger misdirection of the attention than alternative manipulations.
Both Macknik and Martinez-Conde are no strangers to the crossroads of neuroscience and magic. For years, they've written and experimented extensively on this intersection and continue to do so today. Both are columnists for the Scientific American and co-authors of the book "Sleights of Mind."
"Our previous experiments were about discovering new things in science using magic," said Macknik. "This was the first study that we did that was specifically for studying something important about magic using science."
For their experiment, seven participants watched a video of Teller performing the "Cups and Ball" trick. Teller used his right hand to introduce, or load, a small ball inside each of two upside down cups while simultaneously using his left hand to remove a different ball from the upside-down bottom of the cup.