![]() They manipulate the focus and intensity of human attention, controlling, at any given instant, what we are aware of and what we are not. Magicians are, first and foremost, artists of attention and awareness. Thompson’s trick nicely illustrates the essence of stage magic. That gains him an important cognitive advantage-the spectators are not looking for a trick at the critical moment, and so they slightly relax their scrutiny. Second, Thompson performs the real trick only after the audience thinks it is already over. The same temporary blindness can overtake you when you walk from a sunny street into a dimly lit shop. First, the lighting is so bright just before the dress comes off that when it dims, the spectators cannot see the rapid motions of the cables and the white dress as they disappear underneath the stage. ![]() Two other factors help to make the trick work. During that split second, a trap door in the stage opens briefly, and the white dress, held only lightly in place with Velcro and attached to invisible cables leading under the stage, is ripped from her body. The audience will continue to see a red afterimage in the shape of the woman. In this case, the adapting stimulus is the red-lit dress, and Thompson knows that the spectators’ retinal neurons will rebound for a fraction of a second after the lights are dimmed. When the constant stimulus is turned off, the adapted neurons fire a “rebound” response known as an afterdischarge. It is as if neurons actively ignore a constant stimulus to save their strength for signaling that a stimulus is changing. The responsiveness of a neural system to a constant stimulus (as measured by the firing rate of the relevant neurons) decreases with time. The more they stare at her, the less they notice the hidden devices in the floor, and the better adapted their retinal neurons become to the brightness of the light and the color they perceive.Īll during Thompson’s patter after his little “joke,” each spectator’s visual system is undergoing a brain process called neural adaptation. The attractive woman in her tight dress also helps to focus people’s attention right where Thompson wants it-on the woman’s body. ![]() That reasonable assumption, of course, is wrong. As Thompson introduces his assistant, her skintight white dress wordlessly lures the spectators into assuming that nothing-certainly not another dress-could possibly be hiding under the white one. The trick and its explanation by John Thompson (aka the Great Tomsoni) reveal a deep intuitive understanding of the neural processes taking place in the spectators’ brains-the kind of understanding that we neuroscientists can appropriate for our own scientific benefit. But wait! Her dress really has turned red. He claps his hands, and the lights dim again then the stage explodes in a supernova of whiteness. Please, indulge him and direct your attention once more to his beautiful assistant as he switches the lights back on for the next trick. But you have to agree, he did turn her dress red-along with the rest of her. Yes, he admits, it was a cheap trick his favorite kind, he explains devilishly. The magician stands at the side of the stage, looking pleased at his little joke. Whoa, just a moment there! Switching color with the spotlight is not exactly what the audience had in mind. The woman is awash in a flood of redness. Tomsoni claps his hands, and the spotlight dims ever so briefly before reflaring in a blaze of red. On the edge of their seats, the spectators strain to focus on the woman, burning her image deep into their retinas. The Great Tomsoni announces he will change her dress from white to red. The woman in the tiny white dress is a luminous beacon of beauty radiating from the stage to the audience. The spotlight shines on the magician’s assistant.
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