NOTES

1. The Woman in the Chameleon Dress

2 neuromagic: See S. Martinez-Conde and S. L. Macknik (2008), “Magic and the brain,” Scientific American 299: 72–79.

3 Margaret Livingstone’s work: M. S. Livingstone (2000), “Is it warm? Is it real? Or just low spatial frequency?” Science 290: 1299.

8 By definition: See the recent special issue of Scientific American in which we discuss how our visual perception is dominated by illusions. S. Martinez-Conde and S. L. Macknik (2010), “The Science of Perception Special Issue,” Scientific American Special 20(1).

10 To get at the neural correlates of PTSD: Read more at http://www.smithsonianmag.com/science-nature/How-Our-Brains-Make-Memories.html.

11 This is where you first detect the different orientations: The discovery of neurons selective to line orientation won the 1981 Nobel Prize in Physiology or Medicine for David Hubel and his partner, Torsten Wiesel. Once orientation selectivity was discovered, the field of visual neuroscience set out to categorize all of the various types of features encoded by the visual system.

13 You also make up a lot of what you see: A receptive field is a region of space that, when acted upon by a particular stimulus, will cause that neuron to respond. It is the part of your retina that each neuron can see. Haldan Keffer Hartline won a Nobel Prize in Physiology or Medicine in 1967 for showing that the retinal neurons that transmit information to the brain respond best to those parts of a visual scene containing the edges of objects. By adding, subtracting, or even multiplying receptive fields, your brain creates a zoological tree of neurons with individual preferences for various aspects of a visual scene or features of objects.

16 This response causes a ghostly image: S. L. Macknik and M. S. Livingstone (1998), “Neuronal correlates of visibility and invisibility in the primate visual system,” Nature Neuroscience 1(2): 144–49.

17 Auzinger immediately grasped the implications: Ottokar Fisher, Illustrated Magic (New York: Macmillan, 1943).

18 Today a black art act: Two brothers, Joe and Bob Switzer, invented fluorescent paint and Day-Glo paint in the 1930s. Joe wanted to be a magician when he was younger and started fooling around with black light that he and his brother learned to make from Popular Science magazine. They sneaked into their father’s pharmacy and shone light on different chemicals; some glowed brightly. So they mixed chemicals to develop various kinds of paint that fluoresce under ordinary ultraviolet light. Fluorescent pigments seem brighter than standard pigments because they reflect more visible light than they would if they were not fluorescent.

20 “the sky is filled with stars”: All celestial bodies, including galaxies, project dots of light smaller than any photoreceptor in your eye. But then how is it that some stars appear bigger than others? The answer is that some celestial bodies are so bright that the extra light they produce reflects off the back of your retina. This reflection in turn excites many more photoreceptors in a larger circular area. The result is that bright stars seem larger.

2. The Secret of the Bending Spoon

32 Two normal depth perception cues: You may be surprised to learn that the depth perception your brain creates by comparing the images in your two eyes (called stereopsis) is an illusion, wholly a construct of your mind. Your left eye and right eye convey slightly different views of the world to your brain. If you close your left and right eyes in rapid succession and look at an object, you will see that the object shifts left to right. With both eyes open, your brain triangulates these two images into a single stereo image, which gives you a sense of depth. This is the principle behind stereo-depth illusions such as in the Magic Eye books.

How stereopsis is actually accomplished in the brain remains one of the deepest mysteries of visual neuroscience. We know a bit, but relatively little compared to what we know about how other processes, such as motion perception, are accomplished. We know that the information from each eye remains segregated at the level of your optic nerves. We also know that visual information from your two eyes converges onto the same neurons in your primary visual cortex. This means that certain neurons in this brain region can respond to stimuli from either eye or both eyes. They are binocular.

But where in the brain does vision, based on both eyes, come together? Where is the depth of each object in the scene computed? Where do the images fuse into one seamless experience? We know these things must happen. Otherwise we would have double vision instead of depth perception. In our own labs, we have found that the processes used to derive stereoscopic perception must arise several levels above the primary visual cortex in the visual hierarchy. Finding the exact location is an area of active research.

Stereopsis contributes to Vernon’s trick, too, because your two eyes see your card pushed into the deck from different angles. Your brain triangulates these two different retinal images to compute the depth of the card within the deck. It’s an illusion, but stereopsis confirms that the card is mid-deck.

38 Tony took advantage: A. S. Barnhart (in press), “The exploitation of Gestalt principles by magicians,” Perception.

38 Good continuation is so integral to a plethora of brain mechanisms: Ibid.

39 saws a woman in half: This trick can be accomplished in other ways as well. But in all of them good continuation plays a role in the effect.

40 Charles Gilbert and colleagues: M. K. Kapadia, M. Ito, C. D. Gilbert, and G. Westheimer (1995), “Improvement in visual sensitivity by changes in local context: Parallel studies in human observers and in V1 of alert monkeys,” Neuron 15: 843–56.

40 A second concept behind the spoon illusion: It has been published as the “Dancing Bar” illusion by Peter Tse and Brown Hsieh at Dartmouth College. The neural basis of this illusion has been shown by Christopher Pack, now at the Montreal Neurological Institute. P. U. Tse, P.-J. Hsieh (2007), “Component and intrinsic motion integrate in ‘dancing bar’ illusion,” Biological Cybernetics 96(1): 1–8; C. C. Pack and R. T. Born (2001), “Temporal dynamics of a neural solution to the aperture problem in visual area MT of macaque brain,” Nature 409: 1040–42.

40 To localize the ends of a line: C. C. Pack, M. S. Livingstone, K. R. Duffy, and R. T. Born (2003), “End-stopping and the aperture problem: Two-dimensional motion signals in macaque V1,” Neuron 39: 671–80.

3. The Brother Who Faked a Dome

43 For further discussion on how visual art and visual science interact, see S. Martinez-Conde and S. L. Macknik (2010), “Art as Visual Research: Kinetic Illusions in Op Art,” Scientific American Special 20(1): 48–55.

47 Susana’s results showed instead: X. G. Troncoso, S. L. Macknik, and S. Martinez-Conde (2005), “Novel visual illusions related to Vasarely’s ‘nested squares’ show that corner salience varies with corner angle,” Perception 34: 409–20; X. G. Troncoso, P. U. Tse, S. L. Macknik, G. P. Caplovitz, P.-J. Hsieh, A. A. Schlegel, J. Otero-Millan, and S. Martinez-Conde (2007), “BOLD activation varies parametrically with corner angle throughout human retinotopic cortex,” Perception 36: 808–20; X. G. Troncoso, S. L. Macknik, and S. Martinez-Conde (2009), “Corner salience varies linearly with corner angle during flicker-augmented contrast: A general principle of corner perception based on Vasarely’s artworks,” Spatial Vision 22: 211–24.

49 In 2006 we designed an experiment: X. G. Troncoso, S. L. Macknik J. Otero-Millan, and S. Martinez-Conde (2008), “Microsaccades drive illusory motion in the Enigma illusion,” Proceedings of the National Academy of Sciences of the United States of America [hereafter PNAS] 105: 16033–38.

49 Her expression is often: M. S. Livingstone (2000), “Is it warm? Is it real? Or just low spatial frequency?” Science 290: 1299.

51 The Leaning Tower illusion: F. A. A. Kingdom, A. Yoonessi, and E. Gheorghiu (2007), “The Leaning Tower illusion: A new illusion of perspective,” Perception 36(3): 475–77.

52 The only difference between these two faces: R. Russell (2009), “A sex difference in facial pigmentation and its exaggeration by cosmetics,” Perception 38: 1211–19.

53 Some stationary patterns: A. Kitaoka, Trick Eyes: Magical Illusions That Will Activate the Brain (New York: Sterling Publishing, 2005).

54 We called the new illusion: S. L. Macknik and M. S. Livingstone (1998), “Neuronal correlates of visibility and invisibility in the primate visual system,” Nature Neuroscience 1(2): 144–49; S. L. Macknik and M. M. Haglund (1999), “Optical images of visible and invisible percepts in the primary visual cortex of primates,” PNAS 96: 15208–10; S. L. Macknik, S. Martinez-Conde, and M. M. Haglund (2000), “The role of spatiotemporal edges in visibility and visual masking,” PNAS 97: 7556–60; S. L. Macknik and S. Martinez-Conde (2004), “Dichoptic visual masking reveals that early binocular neurons exhibit weak interocular suppression: Implications for binocular vision and visual awareness,” Journal of Cognitive Neuroscience 16: 1049–59; P. U. Tse, S. Martinez-Conde, A. A. Schlegel, and S. L. Macknik (2005), “Visibility, visual awareness, and visual masking of simple unattended targets are confined to areas in the occipital cortex beyond human V1/V2,” PNAS 102: 17178–83; S. L. Macknik (2006), “Visual masking approaches to visual awareness,” Progress in Brain Research 155: 177–215; S. L. Macknik and S. Martinez-Conde (2007), “The role of feedback in visual masking and visual processing,” Advances in Cognitive Psychology 3: 125–52; S. L. Macknik and S. Martinez-Conde, “The Role of Feedback in Visual Attention and Awareness,” in M. S. Gazzaniga, ed., The Cognitive Neurosciences (Cambridge, Mass.: MIT Press, 2009), pp. 1165–79.

4. Welcome to the Show

60 One critical clue: T. Moore and M. Fallah (2004). “Microstimulation of the frontal eye field and its effects on covert spatial attention,” Journal of Neurophysiology 91: 152–62; Z. M. Hafed and R. J. Krauzlis (2010), “Microsaccadic suppression of visual bursts in the primate superior colliculus,” Journal of Neuroscience 30(28): 9542–47; N. L. Port and R. H. Wurtz (2009), “Target selection and saccade generation in monkey superior colliculus,” Experimental Brain Research 192(3): 465–77; J. W. Bisley and M. E. Goldberg (2010), “Attention, intention, and priority in the parietal lobe,” Annual Review of Neuroscience 33: 1–21.

64 Other times you can shift your attention around: Study by Keisuke Fukada and Edward K. Vogel, “Human variation in overriding attentional capture,” Journal of Neuroscience, July 8, 2009.

64 Research shows that: G. F. Woodman and S. J. Luck (2007), “Do the contents of visual working memory automatically influence attentional selection during visual search?” Journal of Experimental Psychology: Human Perception and Performance 33(2): 363–77.

64 “retinotopic” space: R. Desimone and J. Duncan (1995), “Neural mechanisms of selective visual attention,” Annual Review of Neuroscience 18: 193–222.

64 Jose-Manuel Alonso: Our work with Jose-Manuel Alonso also showed that a specific kind of neuron is enhanced during attention in the center of the spotlight, while a different kind of neuron is inhibited during attention in the surrounding regions. The neurons with enhanced firing in the center of the attentional spotlight are known to inhibit other neurons, whereas the neurons with suppressed firing in the surrounding regions are critical to determining the direction of moving objects. These results suggest that the role of top-down attention in the very earliest stages of vision is to suppress the attention-grabbing aspects of objects moving around whatever it is you want to pay attention to. See Y. Chen, S. Martinez-Conde, S. L. Macknik, Y. Bareshpolova, H. A. Swadlow, and J.-M. Alonso (2008), “Task difficulty modulates the activity of specific neuronal populations in primary visual cortex,” Nature Neuroscience 11: 974–82.

69 Arturo de Ascanio: A. Ascanio, The Magic of Ascanio, vol. 1, trans. R. B. Etcheberry (self-published, 2007).

70 Nobel laureate Eric Kandel: E. Kandel, In Search of Memory: The Emergence of a New Science of Mind (New York: W.W. Norton, 2007).

74 Ethological studies: One evolutionary advantage of having a spotlight of attention dissociated from your center of gaze is that it enhances your ability to deceive others. Having a roving spotlight of attention that can point away from your direction of gaze allows you to hide what you are paying attention to (a potential food source, a desirable mate) from competitors. Marc Hauser at Harvard University has shown that monkeys will intentionally look away from hidden food sources in order to mislead other monkeys away from their stash. See M. D. Hauser (1992), “Costs of deception: Cheaters are punished in rhesus monkeys (Macaca mulatta),” PNAS 89(24): 12137–39. The cost of this system is that attending away from the fovea is, by definition, attending to low resolution information. Therefore, hiding your secret interests from those around you must convey an important adaptive edge.

74 In this sense, both macaques: Many other species use deception to maximize survival and reproductive success. Some birds will feign having a broken wing to lure a predator away from the nest: a form of misdirection. Such pretense of weakness is an old strategy in human warfare. Sun Tzu wrote in The Art of War more than two thousand years ago: “All warfare is based on deception. Hence, when able to attack, we must seem unable; when using our forces, we must seem inactive; when we are near, we must make the enemy believe we are far away; when far away, we must make him believe we are near. Hold out baits to entice the enemy. Feign disorder, and crush him.” Other animals rely on camouflage and mimicry for deceptive purposes: some nonpoisonous butterflies evolved the same wing patterns as poisonous species, giving them the advantage of warning off predatory birds.

5. The Gorilla in Your Midst

77 To overcome adaptation: S. Martinez-Conde and S. L. Macknik (2007), “Windows on the mind,” Scientific American 297: 56–63; S. Martinez-Conde, S. L. Macknik, X. G. Troncoso, and T. Dyar (2006), “Microsaccades counteract visual fading during fixation,” Neuron 49: 297–305.

79 You cannot predict: For a more in-depth discussion of these ideas, see S. Martinez-Conde and S. L. Macknik (2008), “Magic and the brain,” Scientific American 299: 72–79; S. L. Macknik, M. King, J. Randi, A. Robbins, Teller, J. Thompson, and S. Martinez-Conde (2008), “Attention and awareness in stage magic: Turning tricks into research,” Nature Reviews Neuroscience 9: 871–79.

79 To describe these methods: Macknik et al., “Attention and awareness in stage magic.”

80 Cognitive neuroscientists: A. Mack and I. Rock, Inattentional Blindness (Cambridge, Mass.: MIT Press, 1998).

80 Can You Keep Us From Reading Your Mind?: From Martinez-Conde and Macknik “Magic and the brain.”

82 Tamariz uses inattentional blindness: Details can be found in his instructional masterpiece, The Five Points of Magic.

85 Our own research: Y. Chen, S. Martinez-Conde, S. L. Macknik, Y. Bereshpolova, H. A. Swadlow, and J. M. Alonso (2008), “Task difficulty modulates the activity of specific neuronal populations in primary visual cortex,” Nature Neuroscience 11: 974–82.

85 The Gorilla in Our Midst experiment: For a wonderful and very entertaining in-depth look at this and related effects, see Chabris and Simons’s new book, The Invisible Gorilla (New York: Crown Archetype, 2010).

85 In 2006, Daniel Memmert: D. Memmert (2006), “The effects of eye movements, age, and expertise on inattentional blindness,” Consciousness and Cognition 15: 620–27.

86 Inattentional blindness: I. E. Hyman Jr., M. Boss, B. M. Wise, K. E. McKenzie, and J. M. Caggiano (2010), “Did you see the unicycling clown? Inattentional blindness while walking and talking on a cell phone,” Applied Cognitive Psychology 24: 597–607.

87 Another of our colleagues: C. Rosen (2008), “The myth of multitasking,” New Atlantis: A Journal of Technology and Society 20: 105–10.

91 In one version: D. J. Simons and D. T. Levin (1998), “Failure to detect changes to people during a real-world interaction,” Psychonomic Bulletin and Review 5: 644–49. See also C. F. Chabris and D. J. Simons, The Invisible Gorilla (New York: Crown Archetype, 2010).

91 The experiment has been replicated many times: The British mentalist and magician Derren Brown loves change blindness and has made several video clips of the trick in London settings, based on the original Simons videos.

95 Slow or gradual changes: Chabris and Simons, The Invisible Gorilla.

6. The Ventriloquist’s Secret

100 Senses not only interact: This research was carried out by Charles Spence, head of the Crossmodal Research Laboratory based at the Department of Experimental Psychology, Oxford University (www.psy.ox.ac.uk/xmodal/default.htm). He is interested in how people perceive the world around them—in particular, how our brains manage to process the information from each of our senses (smell, taste, sight, hearing, and touch) to form the extraordinarily rich multisensory experiences that fill our daily lives. He currently works on problems associated with the design of foods that maximally stimulate the senses, and with the effect of the indoor environment on mood, well-being, and performance.

101 The same goes for skin and sound: By mixing audio with the tactile sense of airflow, researchers at the University of British Columbia in Vancouver—linguistics professor Bryan Gick and his student Donald Derrick—found that perception of certain sounds relies, in part, on being able to feel these sounds. Their paper was published in Nature, November 26, 2009.

101 Your ears can also fool your eyes: L. Shams, Y. Kamitani, and S. Shimojo (2002), “Visual illusion induced by sound,” Cognitive Brain Research 14: 147–52.

102 In the same vein: V. Jousmaki and R. Hari (1998), “Parchment-skin illusion: Sound-biased touch,” Current Biology 8(6): R190.

102 How you feel the world can actually change how you see it: This research was carried out in the lab of Chris Moore at MIT and was published in the April 9, 2009, online edition of Current Biology. Demos of the motion stimuli can be seen at http://web.mit.edu/~tkonkle/www/CrossmodalMAE.html.

102 And then there is the rubber hand illusion: M. Botvinick and J. Cohen (1998), “Rubber hands ‘feel’ touch that eyes see,” Nature 391: 756.

102 The phenomenon is called synesthesia: R. E. Cytowic, Synesthesia: A Union of the Senses, 2nd ed. (Cambridge, Mass.: MIT Press, 2002); R. E. Cytowic, The Man Who Tasted Shapes (Cambridge, Mass.: MIT Press, 2003); R. E. Cytowic and D. M. Eagelman, Wednesday Is Indigo Blue: Discovering the Brain of Synesthesia (Cambridge, Mass.: MIT Press, 2009); J. E. Harrison, Synaesthesia: Classic and Contemporary Readings (Oxford, UK: Blackwell Publishing, 1996); A. N. Rich and J. B. Mattingley (2002), “Anomalous perception in synaesthesia: A cognitive neuroscience perspective,” Nature Reviews Neuroscience 3(1): 43–52; E. M. Hubbard and V. S. Ramachandran (2005), “Neurocognitive mechanisms of synesthesia,” Neuron 48(3): 509–20; J. Simner, C. Mulvenna, N Sagic, E. Tsakanikos, S. Witehrby, C. Fraser, K. Scott, and J. Ward (2006), “Synesthesia: The prevalence of atypical cross-modal experience,” Perception 35: 1024–33.

102 Neuroscientists have identified at least fifty-four varieties of synesthesia: Caltech lecturer in computation and neural systems Melissa Saenz discovered this phenomenon quite by accident. She reported her findings, with neuroscientist Christof Koch, in the August 5, 2008, issue of Current Biology.

103 In mirror touch synesthesia: M. J. Banissy and J. Ward (2007), “Mirror-touch synesthesia is linked with empathy,” Nature Neuroscience 10: 815–16.

103 As for the rest of us: The bouba kiki effect was first observed by the German-American psychologist Wolfgang Kohler. W. Kohler, Gestalt Psychology (New York: Liveright, 1929).

106 Have you ever driven a cat crazy: B. E. Stein, M. A. Meredith, W. S. Honeycutt, and L. McDade (1989), “Behavioral indices of multisensory integration: Orientation to visual cues is affected by auditory stimuli,” Journal of Cognitive Neuroscience 1: 12–24.

106 feature integration theory: A. Treisman and G. Gelade (1980), “A feature-integration theory of attention,” Cognitive Psychology 12(1): 97–136.

108 The concept was first: P. M. Roget (1825), “Explanation of an optical deception in the appearance of the spokes of a wheel seen through vertical apertures,” Philosophical Transactions of the Royal Society of London 115: 131–40; S. L. Macknik (2006), “Flicker fusion,” http://www.scholarpedia.org/article/Flicker_fusion.

109 Max Wertheimer … and Hugo Munsterberg: M. Wertheimer, Drei Abhandlungen zur Gestalttheorie (Erlangen, Germany: Philosophische Akademie, 1925); H. Munsterberg, The Photoplay: A Psychological Study (New York: D. Appelton and Co., 1916).

109 The dumbstruck editor sent: A. R. Luria and J. Bruner, The Mind of a Mnemonist: A Little Book About a Vast Memory (Cambridge, Mass.: Harvard University Press, 1987).

7. The Indian Rope Trick

111 According to Teller: Teller wrote his review in the Sunday New York Times Book Review, February 13, 2005. See http://www.nytimes.com/2005/02/13/books/review/13TELLERL.html.

117 False memories can be devastating: E. F. Loftus, Eyewitness Testimony (Cambridge, Mass.: Harvard University Press, 1996); E. F. Loftus and J. E. Pickrell (1995), “The formation of false memories,” Psychiatric Annals 25(12): 720–25.

118 In one example: E. F. Loftus, “Made in Memory: Distortions in Memory after Misleading Communications,” in G. Bower, ed., The Psychology of Learning and Motivation, vol. 30, Advances in Research and Theory (San Diego: Academic Press, 1993), 187–215.

118 In another classic experiment: E. F. Loftus and J. C. Palmer (1974), “Reconstruction of automobile destruction: An example of the interaction between language and memory,” Journal of Verbal Learning and Verbal Behavior 13: 585–89.

120 Nader demonstrated that: O. Hardt and K. Nader (2009), “A single standard for memory: The case for reconsolidation,” Nature Reviews Neuroscience 10(3): 224–34.

120 “Flashbulb memories”: K. Nader (2003), “Memory traces unbound,” Trends in Neurosciences 26(2): 65–72.

130 In an article for Slate: Joshua Foer, “Forget Me Not,” Slate.com., March 16, 2005 (http://www.slate.com/id/2114925).

8. Expectation and Assumption

139 Theory of False Solutions: J. Tamariz, The Magic Way (Madrid, Spain: Frakson Books, 1988).

144 Eric Kandel: E. Kandel, In Search of Memory: The Emergence of a New Science of Mind (New York: W.W. Norton, 2007).

145 First, a visual region of your brain: R. A. Andersen and C. A. Buneo (2002), “Intentional maps in posterior parietal cortex,” Annual Review of Neuroscience 25: 189–220.

146 Gustav Kuhn, a psychologist and magician: Gustav Kuhn and Micahel F. Land, “There’s more to magic than meets the eye,” Current Biology 16(22): 950–51.

147 If so, the neural correlate: J. A. Assad and J. H. Maunsell (1995), “Neuronal correlates of inferred motion in primate posterior parietal cortex,” Nature 373: 518–21.

147 Subjects were asked to read a list of words: Study described in Blink by Malcolm Gladwell (Boston: Little, Brown, 2005).

148 Being reminded of their gender: Gladwell, Blink.

148 Half of the participants in another study: “Johan C. Karremans, Wolfgang Stroebe, and Jasper Claus, “Beyond Vicary’s fantasties: The impact of subliminal priming and brand choice,” Journal of Experimental Social Psychology 42(6): 792–98.

148 Advertisers use priming: J. L. Harris, J. A. Bargh, and K. D. Brownell (2009), “Priming effects of television food advertising on eating behavior,” Health Psychology 28(4): 404–13.

149 There are certainly other contributors: Most magicians wouldn’t perform this particular version of the trick onstage because it’s not completely fail-safe. We include it here to illustrate priming in magic.

150 Signal detection theory: D. M. Green and J. A. Swets, Signal Detection Theory and Psychophysics (New York: Wiley, 1966).

151 Keith Payne: B. K. Payne (2001), “Prejudice and perception: The role of automatic and controlled processes in misperceiving a weapon,” Journal of Personality and Social Psychology 81: 181–92.

153 Such questions raise a deeper quandary: J. Piaget, The Origins of Intelligence in Children (New York: International University Press, 1952); J. Piaget, The Moral Judgment of the Child (London: Kegan, Paul, Trench, Trubner and Co., 1932).

154 Elizabeth Spelke, a developmental psychologist: E. S. Spelke (1990), “Principles of object perception,” Cognitive Science 14(1): 29–56.

154 Such research also shows that infants have: For a good review, see Laura Kotovsky and Renée Baillargeon, “The development of calibration-based reasoning about collision events in young infants,” Cognition 67(3): 311–51.

155 He notes that infants: See www.cmu.edu/cmnews/030625/03625_cognition.html.

156 The famous Sally-Ann test: H. Wimmer and J. Perner (1983), “Beliefs about beliefs: Representation and constraining function of wrong beliefs in young children’s understanding of deception,” Cognition 13: 103–28.

157 “Adults can follow directions”: J. Columbo, “Visual Attention in Infancy: Process and Product in Early Cognitive Development,” in Alison Gopnik, The Philosophical Baby (New York: Farrar Straus and Giroux, 2009).

157 In an experiment by John Hagen: J. W. Hagen and G. H. Hale, “The Development of Attention in Children,” in A. D. Pick, ed., Minnesota Symposia on Child Psychology (Minneapolis: University of Minnesota Press, 1973).

158 Silly Billy: D. Kaye, Seriously Silly: How to Entertain Children with Magic and Comedy (Washington, D.C.: Kaufman & Co., 2005).

9. May the Force Be with You

168 The effect is astounding: The mathematical explanation for this trick can be found at www.numericana.com.magic.htm.

172 Here is Dr. Anna Berti: A. Berti, G. Bottini, M. Gandola, L. Pia, N. Smania, A. Stracciari, I. Castiglioni, G. Vallar, and E. Paulesu (2005), “Shared cortical anatomy for motor awareness and motor control,” Science 309: 488–91.

173 choice blindness: P. Johansson, L. Hall, S. Sikstrom, and A. Olsson (2005), “Failure to detect mismatches between intention and outcome in a simple decision task,” Science 310: 116–19.

173 Johansson explains that their experiments were inspired: See Richard E. Nisbett and Timothy D. Wilson (1977), “Telling more than we can know: Verbal reports on mental processes,” Psychological Review 8: 231–59, and http://en.wikipedia.org/wiki/introspection_illusion.

175 In a follow-up experiment: The studies about preferences for jam and tea and the magic questionnaire have been submitted for publication. For the latest updates, see Petter Johansson’s Web site, http://www.lucs.lu.se/petter.johansson/.

176 Again, the results show that a majority of the participants are blind: See Johansson and Hall’s Web site (http://www.lucs.lu.se/projects/choiceblindness) and a YouTube video (http://www.youtube.com/watch?v=WBO03PngZPU).

178 Our colleagues Apollo Robbins … and … Eric Mead: See video at http://www.sfn.org/index.aspx?pagename=am2009_highlights.

180 In the 1970s: The original paper is B. Libet, C. A. Gleason, E. W. Wright, and D. K. Pearl (1983), “Time of conscious intention to act in relation to onset of cerebreal activity (readiness-potential),” Brain 106: 623–42.

181 A politician in the mayor’s office: See http://www.youtube.com/watch?v=-o_pYTOodu4.

183 John-Dylan Haynes: C. S. Soon, M. Brass, H. J. Heinze, and J. D. Haynes (2008), “Unconscious determinants of free decisions in the human brain,” Nature Neuroscience 11(5): 543–45.

186 We may believe that they are connected to free will: See the work of John Bargh at Yale, http://www.yale.edu/psychology/FacInfo/Bargh.html.

186 The illusion of the magic self cannot be easily suppressed: One of the more interesting findings in the free will literature is that when people believe, or are led to believe, that free will is an illusion, they may become more antisocial. Kathleen Vohs from the University of Minnesota and Jonathan Schooler from the University of British Columbia brought thirty students into their lab for a study that was supposedly about mental arithmetic. The students were asked to calculate answers to twenty simple math problems in their heads. Before taking the test, however, half read this passage from Francis Crick’s book The Astonishing Hypothesis: “ ‘You,’ your joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will, are in fact no more than the behavior of a vast assembly of nerve cells and their associated molecules. Who you are is nothing but a pack of neurons … although we appear to have free will, in fact, our choices have already been predetermined for us and we cannot change that.” The other fifteen students read a different passage that did not mention free will. Later, given the chance, the students who read the more neutral passage cheated less than the group who had read that free will is an illusion. For a discussion of this experiment, see http://www.scientificamerican.com/article.cfm?id=scientists-say-free-will-probably-d-2010-04-06. See also D. M. Wegner, The Illusion of Conscious Will (Cambridge, Mass.: MIT Press, 2002).

186 Moreover, many philosophers and scientists argue: See Daniel C. Dennett, Freedom Evolves (New York: Viking Penguin, 2003).

10. Why Magic Wands Work

189 the ideomotor effect: Dowsing is a type of divination used in attempts to locate groundwater, buried metals or ores, gems, oil, graves, and other objects beneath the surface of the earth. The dowser holds a Y-shaped rod that magically “bends” when the dowser is standing over the sought target. Automatic writing is the process of writing that does not stem from conscious thought; it is done by people in a trance state. Facilitated communication is a process by which a facilitator supports the hand or arm of an impaired person—often someone with autism—to help them write and communicate. All three practices are examples of the ideomotor effect.

194 But nobody ever fails: The season two finale of the TV show Lost revealed that pushing the button indeed discharged an electromagnetic field that would otherwise continue to grow until ultimately causing the end of the world. Thus pushing the button to avert world-scale destruction turned out to be a real cause-effect relationship rather than an illusory correlation. But at the beginning of the season, when the characters resign themselves to push the apparently ineffectual button every 108 minutes, they have no factual data that the correlation is real.

194 a team of cognitive neuroscientists: B. A. Parris, G. Kuhn, G. A. Mizon, A. Benattayallah, and T. L. Hodgson (2009), “Imaging the impossible: An fMRI study of impossible causal relationships in magic tricks,” Neuroimage 45(3): 1033–39.

194 Your implicit system of knowledge of cause and effect: See Neuroimage 45(3): 1033–39.

195 ACC, detects conflict: M. M. Botvinick, T. S. Braver, D. M. Barch, C. S. Carter, and J. D. Cohen (2001), “Conflict monitoring and cognitive control,” Psychological Review 108: 624–52.

199 If the mentalist never misses: Credit for this observation goes to Magic Tony.

207 Some people looked: A. Raz, T. Shapiro, J. Fan, and M. I. Posner (2002), “Hypnotic suggestion and the modulation of Stroop interference,” Archives of General Psychiatry 59: 1155–161.

208 Sixteen people … came into Raz’s lab: Cortex 44(10): 1336–41.

209 COMT may confer susceptibility: P. Lichtenberg, R. Bachner-Melman, I. Gritsenko, and R. P. Ebstein (2000), “Exploratory association study between catechol-O-methyltransferase (COMT) high/low enzyme activity polymorphism and hypnotizability,” American Journal of Medical Genetics 96(6): 771–74.

210 “In fact, I was the victim”: See Zak’s blog: http://www.psychologytoday.com/blog/the-moral-molecule.

214 Oxytocin causes us to empathize with others: A recent study indicates that oxytocin is not all touchy-feely. Experimental subjects who inhaled oxytocin while playing a competitive game in the laboratory experienced stronger feelings of envy and gloating than subjects exposed to a placebo. The researchers speculated that oxytocin might intensify social emotions in general, leading to generosity and trust in positive situations and to envy and gloating in competitive scenarios. See http://www.scientificamerican.com/article.cfm?id=oxytocin-hormone.

214 With a magician, you know you’re being scammed: See Paul Zak’s blog in Psychology Today, November 13, 2008. His book The Moral Molecule will be published in 2012 by Dutton.

11. The Magic Castle

222 Professional pianists (and magicians!): A. Pascual-Leone, D. Nguyet, L. G. Cohen et al. (1995), “Modulation of muscle responses evoked by transcranial magnetic stimulation during the acquisition of new fine motor skills,” Journal of Neurophysiology 74: 1037–45; A. Pascual-Leone (2006), “The brain that plays music and is changed by it,” Annals of the New York Academy of Sciences 930: 315–29.

222 Here is one more: S. Blakeslee and M. Blakeslee, The Body Has a Mind of Its Own (New York: Random House, 2007).

222 The dance has become part of his being: See Blakeslee and Blakeslee, The Body Has a Mind of Its Own. See http://www.youtube.com/watch?v=-X0AamE1Bxs for an idea of what happens if you learn the samba as a baby.

225 They are so good: M. Natter and F. Phillips (2008), “Deceptive biological motion: Understanding illusionary movements,” Journal of Vision 8(6): 1052.

232 The sheikh nearly fainted: In 1856, Louis-Napoleon asked Robert-Houdin to convince certain Arab chieftains that the French war machine had magical powers. Religious tribal leaders called marabouts, who used magic to control their followers, had advised their chieftains to break with the French. Napoleon wanted Robert-Houdin to convince the Arabs that French magic was stronger than Arab magic—thus avoiding a war in Algeria. One evening in a stifling hot theater in Algiers, Robert-Houdin demonstrated his powers to the assembled chieftains. He produced a cannonball from a hat. He passed around an inexhaustible bottle that dispensed hot coffee. But his pièce de résistance was issued as a challenge: “I can deprive the most powerful man of his strength and restore it at my will,” said the French magician. “Anyone who thinks himself strong enough to try to experiment may draw near me.” A muscular man approached. “Are you very strong?” “Oh, yes.” “Are you sure you will always remain so?” “Quite sure,” the man replied.

“You are mistaken,” said Robert-Houdin, “for in an instant I will rob you of your strength and you shall become as a little child.” Pointing to a small wooden box, he said, “Lift up this box.” The man lifted the box and laughed. “Is that all?”

Robert-Houdin said “Wait!” and then, making an imposing gesture, “Behold.” He waved his magic wand. “Now you are weaker than a woman. Try to lift the box.” The man tried. He pulled with all his might. Sweat poured down his face. He tried to rip the box apart, to no avail. You see, the box contained a powerful electromagnet, which exerted a force unknown to the marabouts. Robert-Houdin then delivered an electric shock to the man, who ran screaming off the stage.

With this display of French supernatural power, the rebellion was put down.

235 In 2007, a retired CIA officer: H. Keith Melton and Robert Wallace, The Official CIA Manual of Trickery and Deception (New York: William Morrow, 2009).

12. Will the Magic Go Away?

250 Your mirror neuron system: S. Blakeslee and M. Blakeslee, The Body Has a Mind of Its Own (New York: Random House, 2007).

250 The same goes for athletics: B. Calvo-Merino, D. E. Glaser, J. Grezes, R. E. Passing-ham, and P. Haggard (2005), “Action observation and acquired motor skills: An fMRI study with expert dancers,” Cerebral Cortex 15(8): 1243–49.

252 And it could work the other way around: Magicians are beginning to use in their stage acts perceptual effects originally designed for scientific experiments. Derren Brown and Penn & Teller execute change blindness routines that are firmly rooted in the cognitive sciences. Teller says of the change blindness routine in the Penn & Teller act, “The idea came straight from science. We thought it would be fun to show how bad they are at noticing stuff” (J. Lehrer, “Magic and the brain: Teller reveals the neuroscience of illusion,” Wired.com, April 20, 2009).

255 You might wonder: In fact, a few of our colleagues, led by Peter Lamont, a lecturer in psychology at the University of Edinburgh, have made this suggestion.

257 We believe it also determines: Y. Chen, S. Martinez-Conde et al. (2008), “Task difficulty modulates the activity of specific neuronal populations in primary visual cortex,” Nature Neuroscience 11(8): 974–82.