The Invisible Gorilla: And Other Ways Our Intuitions Deceive Us

by Christopher Chabris

  35. A recent “cure” for autism, promoted by believers in the vaccine theory, involves large doses of the drug Lupron, which suppresses testosterone. Lupron is occasionally used to chemically castrate violent sex offenders. It might well lead to more docile behavior, but so would a frontal lobotomy. Unlike changing a child’s diet, administering Lupron could have substantial negative side effects, such as delayed puberty and heart and bone problems, not to mention regular, painful injections. The prime promoters of the drug as an autism therapy have conducted no clinical trials and have no special training in the medical subfields related to autism, and no scientific studies have ever been conducted on the use of the drug in autism. For some details on this “therapy” and its promoters, see T. Tsouderos, “Miracle Drug Called Junk Science,” Chicago Tribune, May 21, 2009 (www.chicagotribune.com/health/chi-autism-lupron-may21,0,242705.story).

  36. Retrieved from Amazon.com on July 27, 2009.

  37. From the representative national poll conducted by SurveyUSA on our behalf in June 2009 (see notes to Chapter 1 for details).

  38. For a discussion of such differences, see D. C. Penn, K. J. Holyoak, and D. J. Povinelli, “Darwin’s Mistake: Explaining the Discontinuity Between Human and Nonhuman Minds,” Behavioral and Brain Sciences 31 (2008): 109–178.

  Chapter 6: Get Smart Quick!

  1. R. Cimini, “Mangini Gets Players Tuned In,” New York Daily News, July 31, 2007 (www.nydailynews.com/sports/football/jets/2007/07/31/2007-07-31_mangini

  _gets_players_tuned_in.html).

  2. S. Yun, “Music a Sound Contribution to Healing: Good Samaritan Taking Cacophony Out of Hospital Care,” Rocky Mountain News, May 31, 2005, www.mozarteffect.com/RandR/Doc_adds/RMNews.htm (accessed June 24, 2009).

  3. Zell Miller gave his speech on June 22, 1998, and requested $105,000 of public funds, according to “Random Samples,” Science, January 30, 1998 (www.scienceonlineorg/cgi/content/summary/279/5351/663d).

  4. “Slovak Hospital Plays Mozart to Babies to Ease Birth Trauma,” Agence FrancePresse, September 10, 2005, www.andante.com/article/article.cfm?id=25923 (accessed May 29, 2009).

  5. F. H. Rauscher, G. L. Shaw, and K. N. Ky, “Music and Spatial Task Performance,” Nature 365 (1993): 611.

  6. Shaw described this idea as a “bold prediction” in the report on the Mozart effect done by the Fox Family Channel on their program “Exploring the Unknown” (broadcast in 1999).

  7. G. L. Shaw, Keeping Mozart in Mind, 2nd ed. (San Diego, CA: Academic Press, 2004), 160. You may be reminded of our comments in Chapter 4 on “neurobabble” as you read these claims about a special relationship between Mozart’s music and the workings of the brain.

  8. Mozart biographer Alfred Einstein, quoted by Shaw (Keeping Mozart in Mind, 162).

  9. R. A. Knox, “Mozart Makes You Smarter, Calif. Researchers Suggest,” The Boston Globe, October 14, 1993.

  10. According to a report on NBC Nightly News, August 1999.

  11. No studies have ever tested infants, a fact noted by Rauscher herself in a quote here: “Random Samples,” Science, January 30, 1998 (www.scienceonline.org/cgi/content/summary/279/5351/663d).

  12. Followup studies by Rauscher and her colleagues included the following (among others): F. H. Rauscher, G. L. Shaw, and K. N. Ky, “Listening to Mozart Enhances Spatial-Temporal Reasoning: Towards a Neurophysiological Basis,” Neuroscience Letters 185 (1995): 44–47; and F. H. Rauscher, K. D. Robinson, and J. J. Jens, “Improved Maze Learning Through Early Music Exposure in Rats,” Neurological Research 20 (1998): 427–432.

  13. C. Stough, B. Kerkin, T. Bates, and G. Mangan, “Music and Spatial IQ,” Personality and Individual Differences 17 (1994): 695.

  14. All studies of the Mozart effect conducted up to the summer of 1999 are summarized in C. F. Chabris, “Prelude or Requiem for the ‘Mozart Effect’?” Nature 400 (1999): 826–827.

  15. K. M. Steele, K. E. Bass, and M. D. Crook, “The Mystery of the Mozart Effect: Failure to Replicate,” Psychological Science 10 (1999): 366–369.

  16. According to a personal communication between Chris and Kenneth Steele, June 13, 2009.

  17. K. M. Steele, “The ‘Mozart Effect’: An Example of the Scientific Method in Operation,” Psychology Teacher Network, November–December 2001, pp. 2–3, 5.

  18. Mentioned in Kevin Kwong’s review of upcoming music and theater events in the South China Morning Post entitled “Just the Ticket,” August 25, 2000.

  19. A. Bangerter and C. Heath, “The Mozart Effect: Tracking the Evolution of a Scientific Legend,” British Journal of Social Psychology 43 (2004): 605–623. This paper argues that coverage of the Mozart effect supports the theory that rumors and legends spread because they “address the needs or concerns of social groups.” We agree, and we argue further that the particular need involved here is the need to believe that all of us have untapped mental potential that can easily be released. Adrian Bangerter published an expanded version in French as La diffusion des croyances populaires: Le cas de l’effet Mozart (Grenoble: Presses Universitaires de Grenoble, 2008).

  20. The most famous exposition of this argument appears in S. J. Gould, The Mismeasure of Man (New York: Norton, 1981).

  21. Sir Francis Galton performed this experiment at a country fair in England and reported it in this article: F. Galton, “Vox Populi,” Nature 75 (1907): 450–451. For more on this topic, see J. Surowiecki, The Wisdom of Crowds (New York: Doubleday, 2004); and C. Sunstein, Infotopia: How Many Minds Produce Knowledge (New York: Oxford University Press, 2006).

  22. E. G. Schellenberg and S. Hallam, “Music Listening and Cognitive Abilities in 10 and 11 Year Olds: The Blur Effect,” Annals of the New York Academy of Sciences 1060 (2005): 202–209.

  23. K. M. Nantais and E. G. Schellenberg, “The Mozart Effect: An Artifact of Preference,” Psychological Science 10 (1999): 370–373.

  24. In addition to the “Blur Effect” study mentioned earlier, two other published studies have failed to find a Mozart effect in school-age children: P. McKelvie and J. Low, “Listening to Mozart Does Not Improve Children’s Spatial Ability: Final Curtains for the Mozart Effect,” British Journal of Developmental Psychology 20 (2002): 241–258; and R. Crncec, S. J. Wilson, and M. Prior, “No Evidence for the Mozart Effect in Children,” Music Perception 23 (2006): 305–317. The mistaken impression that the Mozart effect works best with fetuses, which led some parents to play classical music to their unborn children by wrapping headphones around the mothers’ bellies, might have arisen from publicity given to another finding by Rauscher, published in another obscure journal. She reported exposing rats to the magical Mozart sonata for 60 days in utero, plus several days after they were born, and comparing these animals with a control group for maze-running ability. The Mozart-exposed rats did better (Rauscher, Robinson, and Jens, “Improved Maze Learning”). Rauscher’s bête noire, Kenneth Steele, later pointed out that limitations on the auditory perception abilities of rats prevent them from hearing many of the notes in the sonata. See K. M. Steele, “Do Rats Show a Mozart Effect?” Music Perception 21 (2003): 251–265. However, Rauscher continued to trumpet her rat studies, claiming that gene expression was different in the brains of Mozart-exposed rats compared with control rats. See F. H. Rauscher, “The Mozart Effect in Rats: Response to Steele,” Music Perception 23 (2006): 447–453. This is not surprising, of course: The brain processes music—it doesn’t go in one ear and out the other—so one would expect to find some difference between brains exposed to even just a few notes of music and brains exposed to something else. Finding such a difference, whether in gene expression, blood flow, electrical activity, or whatever, is irrelevant to the debate over the Mozart effect unless the difference is linked to a change in performance that is specific to Mozart’s music, and not just a consequence of changes in mood or arousal that could result from many different kinds of stimulation.

  25. B. Mook, “In a ‘Tot’-anic Size ’01 Deal, Disney Buys Baby Einstein,” Denver Business Journal,
March 1, 2002 (www.bizjournals.com/denver/stories/2002/03/04/focus9.html).

  26. V. C. Strasburger, “First Do No Harm: Why Have Parents and Pediatricians Missed the Boat on Children and the Media?” Journal of Pediatrics 151 (2007): 334–336.

  27. F. J. Zimmerman, D. A. Christakis, and A. N. Meltzoff, “Associations Between Media Viewing and Language Development in Children Under Age 2 years,” Journal of Pediatrics 151 (2007): 364–368. The CDI gives a percentile score for a child based on how many of the ninety words he or she knows and says; the estimate of 8 percent reduction per hour of viewing is based on a drop of seventeen percentile points. That is, consider Jane and Tanya, two children from similar families and with similar experiences, differing only in that Jane never watches baby DVDs but Tanya watches them for an hour per day. If Jane has an average vocabulary for her age (i.e., she is at the 50th percentile), then Tanya would be expected to be at the 33rd percentile, and to use 8 percent fewer words than Jane. Smaller-scale studies have found similar negative effects for some educational TV programming; e.g., see D. L. Linebarger and D. Walker, “Infants’ and Toddlers’ Television Viewing and Language Outcomes,” American Behavioral Scientist 48 (2005): 624–645.

  28. R. Monastersky, “Disney Throws Tantrum Over University Study Debunking Baby DVDs and Videos,” Chronicle of Higher Education News Blog, August 14, 2007 (chronicle.com/news/article/2854/disney-throws-tantrum-over-university-study-debunking-baby-dvds-and-videos).

  29. Disney spokesman Gary Foster was quoted in H. Pankratz, “Retraction Demanded on ‘Baby Einstein,’” The Denver Post, August 14, 2007 (www.denverpost.com/news/ci_6617051). In September 2009, Disney announced that it would offer refunds to purchasers of Baby Einstein DVDs during the previous five years. See T. Lewin, “No Einstein in Your Crib? Get a Refund,” The New York Times, October 23, 2009, p. A1.

  30. Information about Eric Mangini’s coaching career from Wikipedia, en.wikipedia.org/wiki/Eric_Mangini (accessed June 16, 2009). Of course, it would be wrong to conclude that adding Mozart caused his team’s decline—beware the illusion of cause! Most likely it had no effect whatsoever.

  31. For a discussion of the effects of hypnosis on memory accuracy (and confidence), see J. F. Kihlstrom, “Hypnosis, Memory and Amnesia,” Philosophical Transactions of the Royal Society of London B 352 (1997): 1727–1732.

  32. Even though people aren’t well-informed about the reality of hypnosis and memory, the legal system does look askance at witnesses whose memory has been hypnotically enhanced, or who request hypnosis to help them remember. Recall Kenny Conley, the Boston cop who was convicted of perjury and obstruction of justice for his testimony that he never saw Michael Cox at the fence. A witness’s request to be hypnotized to improve his memory was at the core of the technicality that got his conviction reversed—the request undermined the witness’s credibility, and the prosecution failed to disclose it to the defense.

  33. After an exhaustive search, Barry Beyerstein of Simon Fraser University wrote, “I confess that I have been frustrated in my attempts to unearth the ultimate source of the 10% myth … there is little doubt that the primary disseminators (not to mention beneficiaries) of the 10% myth have been the touts and boosters in the ranks of the self-improvement industry, past and present.” See B. L. Beyerstein, “Whence Cometh the Myth That We Only Use 10% of Our Brains?” in Mind Myths: Exploring Popuhr Assumptions About the Mind and Brain, ed. S. Della Salla, 3–24 (Chichester, UK: Wiley, 1999).

  34. E. B. Titchener, “The ‘Feeling of Being Stared At,’” Science 8 (1898): 895–897.

  35. See J. E. Coover, “The Feeling of Being Stared At,” The American Journal of Psychology 24 (1913): 570–575. Our survey result replicates laboratory studies conducted by Jane Cottrell and Gerald Winer showing that college students as well as children believe that they can feel the stares of unseen others. See J. E. Cottrell, G. A. Winer, and M. C. Smith, “Beliefs of Children and Adults About Feeling Stares of Unseen Others,” Developmental Psychology 32 (1996): 50–61.

  36. Some promoters of paranormal phenomena still argue in favor of the idea that people can perceive the stares of others, typically attributing the effect to mysterious effects in quantum mechanics. The methods are often suspect, and none of the studies have been published in mainstream scientific journals. As was the case for the Mozart effect, proponents of the idea that people can feel the stares of others often appeal to other studies replicating the effect, but those other results are not published in mainstream journals. For a discussion by a proponent of these effects, see D. Radin, Entangled Minds (New York: Paraview Press, 2006), 125–130. For critiques of their evidence, see M. Shermer, “Rupert’s Resonance,” Scientific American, November 2005 (www.scientificamerican.com/article.cfm?id=ruperts-resonance); D. F. Marks and J. Colwell, “The Psychic Staring Effect: An Artifact of Pseudo Randomization,” Skeptical Inquirer, September/October 2000 (www.csicop.org/si/show/psychic_staring_effect_an_artifact_of

  _pseudo_randomization/). Note that we are not saying that what is published in reputable scientific journals is always correct, or that what gets shut out of those journals must be false. There are fads, fashions, and judgment calls in science, and our own papers are not always published in the most prestigious venues (even if they should be!). But for any given phenomenon, if no mainstream scientific journals will publish it, there’s an excellent chance it is not based on solid, replicable scientific evidence.

  37. W. B. Key, Subliminal Seduction (New York: Prentice Hall, 1973). The Vicary experiment is described on pages 22–23, and the “man” experiment is described on pages 29–30.

  38. On page 30 of Key’s book, the raw data from this experiment are presented in table form. We used his data to calculate that the size of the difference between the control and the subliminal message conditions was large: approximately one standard deviation. The probability that this difference could have arisen just due to chance was anastonishingly small .0000000001—in other words, it likely was too good to be true. The scientific evidence for subliminal perception, to the extent that it meets rigorous standards and can be reproduced reliably, typically shows small effects, mostly in the speed with which people can respond. And the effects tend to be short-lived. There is still debate in the scientific literature on whether this sort of perception in the absence of awareness even exists at all. For a discussion of some of the challenges involved in demonstrating subliminal perception, see D. Hannula, D. J. Simons, and N. Cohen, “Imaging Implicit Perception: Promise and Pitfalls,” Nature Reviews Neuroscience 6 (2005): 247–255.

  39. The best account of the truth behind Vicary’s “experiment” is found in this article: A. R. Pratkanis, “Myths of Subliminal Persuasion: The Cargo-Cult Science of Subliminal Persuasion,” Skeptical Inquirer 16 (1992): 260–72.

  40. See Hannula et al., “Imaging Implicit Perception.” The debate is over what it means to say that something was not consciously perceived, and the methods used to assess precisely how much people are aware of. Most scientists, even those who are proponents of the idea that subliminal perception is a robust phenomenon, agree that any effects of the meaning of an unseen stimulus on cognition will tend to be fairly small, and most doubt that subliminal stimuli can persuade us to do something we wouldn’t otherwise do.

  41. A recent article has made an even stronger claim than the original one made by Vicary. This study showed that subliminally flashing the Israeli flag led Israeli subjects to substantially change their strongly held views on Palestinian statehood and settlements in Gaza. Both those who strongly opposed statehood and those who favored it moderated their views, becoming indistinguishable from each other. Even more amazing, the subliminal flags changed whom the subjects voted for, again in the direction of moderation, this time weeks after the study! To us, this study illustrates how readily people will accept what are fantastical claims when they involve the release of untapped potential to change our minds. The mechanism proposed in the paper, that seeing a flag would implicit
ly lead to more centrist views, fits only one explanation, generated after seeing the results. It seems more plausible to us that seeing a flag, if it has any effect at all, should make people’s views more extreme. Most people believe themselves to be patriotic, and seeing a flag should only strengthen their existing views; it should not cause them to become more centrist. Although the result might be legitimate and replicable, given the ease with which we can succumb to the illusion of untapped potential, we think skepticism is warranted in the face of such a startling finding. It is hard to imagine such a minimal experience changing someone’s sincere views so radically, especially considering that they are exposed to so many more direct attempts at persuasion. The original study is R. R. Hassin, M. J. Ferguson, D. Shidlovski, and T. Gross, “Subliminal Exposure to National Flags Affects Political Thought and Behavior,” Proceedings of the National Academy of Sciences 104 (2007): 19757–19761.

  42. A. G. Greenwald, E. R. Spangenberg, A. R. Pratkanis, and J. Eskenazi, “Double-Blind Tests of Subliminal Self-Help Audiotapes,” Psychological Science 2 (1991): 119–122. According to this rigorous study by four research psychologists, these recordings do appear to induce nonspecific placebo effects, because their listeners use them desiring and expecting to improve their mental function. They also leave some of their users with an illusion of having received the specific benefits sought, even when they haven’t.

  43. B. Mullen et al., “Newscasters’ Facial Expressions and Voting Behavior: Can a Smile Elect a President?” Journal of Personality and Social Psychology 51 (1986): 291–295.