The Rational Animal: How Evolution Made Us Smarter Than We Think

by Kenrick, Douglas T.

  Yet we do already share one commonality with J. K. Rowling. And you probably do too. That commonality is the secret of Rowling’s success. Whether we’re British, Bostonian, or Bangladeshi, whether our sex chromosomes are XY or XX, and whether we’re seven years old or seventy, we all love a mystery.

  A couple of years back, Doug read all 4,091 pages of the seven Harry Potter books to his seven-year-old son, who devoured every word. As each night’s reading session came to a close, the mesmerized little tyke would plead, “Please, Daddy, just a few more pages!” What he didn’t know was that dad wanted to read a few more pages too. What kept us, and hundreds of millions of other readers, entranced was Rowling’s masterful ability to keep up the mystery. Every time Harry Potter and his friends Hermione Granger and Ron Weasley solved one puzzle, another, even more intriguing mystery arose.

  The topic of mystery brings us back to the real reason that we wrote this book. Science is all about solving mysteries. And the question of what underlies our own human choices is one of the greatest mysteries of all time. It’s a wonderfully complex plot, and the scientists who have been investigating it have traced a labyrinth of clues—from evolutionary biology, cognitive psychology, anthropology, and economics. What makes science so appealing, and what keeps the scientific detectives so incredibly excited, is the fact that resolving one puzzle opens up new and more intriguing mysteries.

  The mystery of human behavior is part of the same plot as why peacocks flaunt their feathers, why squirrels altruistically sacrifice themselves, and why cuckoos exploit unsuspecting neighbors. The reasons behind your choices are part of the same thread that links the choices of jungle dwellers in the Amazon, hunter-gatherers in Africa, and chic urbanites hunting for fame and fortune in the jungles of Manhattan. Uncovering these connections and piecing together the clues will help us all become wiser decision makers. But most of the threads in this grand story have yet to be unraveled. Our hope is that some of the people who read this book will be inspired to pick up a Sherlock Holmes–style magnifying glass, join the other detectives working the case, and help solve the mystery of the human mind. The next clue is waiting just around the corner.

  Acknowledgments

  Every time we watch the credits roll at the end of a movie, we’re always astounded by the number of people it takes to turn an idea into a complete film. Books are no different. Scores of individuals behind the scenes helped us turn a few raw ideas into a book.

  Before we ever put pen to paper, our thinking was shaped by years of thought-provoking conversations about economic decision making with our colleagues and collaborators Bob Cialdini, Steve Neuberg, Jill Sundie, Norm Li, Mark Schaller, Noah Goldstein, Vaughn Becker, Andy Delton, Tess Robertson, Josh Ackerman, Jeff Simpson, Adam Cohen, Josh Tybur, Joe Redden, Jessica Li, Lani Shiota, Kristina Durante, Sarah Hill, Becca Neel, Andrew White, Jenessa Shapiro, Chad Mortensen, and Lionel Nicastle. Each of these brilliant folks helped sharpen our thinking about the topic and teach old dogs some new tricks. We are likewise indebted to our colleagues and students at Arizona State University and the University of Minnesota, who both supported and challenged us, preventing us from getting lazy and forcing us to think harder.

  Our thinking about the evolutionary roots of decision making was enlightened by the great work of our many brilliant and highly productive colleagues, including Martie Haselton, Leda Cosmides, John Tooby, David Buss, Martin Daly, Margo Wilson, Robert Frank, Mark van Vugt, X. T. Wang, Jon Maner, Peter Todd, Geoffrey Miller, Rob Kurzban, Athena Aktipis, Daniel Nettle, Gerd Gigerenzer, Gad Saad, Steve Gangestad, Bill von Hippel, Andreas Wilke, Bruce Ellis, Jay Belsky, Steven Pinker, Dan Barrett, Dan Fessler, Deb Lieberman, Carlos Navarrete, and A. J. Figueredo. Your creative work inspired many fruitful ideas.

  Although we have spent most of our writing careers working on scientific journal articles, both of us were inspired to branch out after taking a graduate seminar in scientific writing taught by one of our favorite science writers, John Alcock. Your reading experience throughout this book has been thoroughly improved not only by his teachings but by multiple colleagues and friends who read various versions of this book and provided detailed feedback, including Josh Ackerman, Mark Bergen, Robert Cialdini, Andy Delton, Kristina Durante, Sarah Hill, George John, Akshay Rao, Joe Redden, Jeff Simpson, David Lundberg Kenrick, Geoffrey Miller, Josh Tybur, Kevin Upton, Bram Van den Bergh, Kathleen Vohs, Jianfeng Yu, and Dong Zee. We are also thankful to several doctorate students who provided insightful feedback on the book, including Stephanie Cantu, Michael Covey, Chiraag Mittal, Nick Olson, and Ethan Young.

  Doug’s thinking about evolution and behavior was powerfully influenced by years of fascinating conversations with his friends Rich Keefe, Ed Sadalla, and Mark Schaller, often conducted during long walks or delicious meals. Speaking of delicious meals, Carol Luce not only provided five-star sustenance while Doug was working on this book, but also accompanied that fine cuisine with insightful intellectual nourishment and various tips for cooking and preparing the ideas presented in these pages. David Lundberg Kenrick has not only become Doug’s other intellectual companion but has also used his extensive video-production skills to help bring some of these ideas to cinematic life (as you can see if you search on YouTube for “How Mating and Self-Protection Motives Alter Loss Aversion” or “Kenrick–The Rational Animal”). Dave’s younger brother, Liam, helped Doug learn about J. K. Rowling by encouraging him to carefully read all the Harry Potter books, which also helped ameliorate any inclination to write in the style of a scientific journal article. Grandma Jean Luce also found other things to entertain Liam, generously freeing Doug up to write anything at all.

  Vlad is indebted to Elliot Aronson and Anthony Pratkanis for inspiring him to pursue social psychology and to Bob Cialdini and Doug Kenrick (before he was a coauthor) for teaching him how to think both inside and outside the box. Vlad’s parents, Antanas and Danute, gave him the invaluable gifts of opportunity and trust, providing him the opportunity to pursue whatever he wanted, while always trusting that he would figure things out. And big brother Agnius encouraged him to boldly explore the universe of ideas. Vlad is also appreciative for years of friendship with Gil Koresh, Paul Zahka, Anuranjan Singh, Brennan Diamond, Darren Weiss, Taylor Umlauf, and Josh Sorkin, who provided companionship and many life lessons during road trips, spring-training games, and garage-band practices. Particular thanks to Gil, who was always there for a walk and a deep conversation. Vlad hopes to continue those deep conversations with his growing kids, Greta, Nora, and Nicholas, who constantly provide a new life perspective and a reminder to take joy in life’s little things. Speaking of the kids, Nana Charynanne provided endless hours of much-appreciated loving care. And, of course, Vlad is deeply indebted and thankful to his loving and devoted wife, Jenny, who selflessly does countless things every day that enable him to keep his sanity and provide him time to write. I love you.

  Both Doug and Vlad are also deeply grateful to our supportive editor, T. J. Kelleher; our production editor, Sandra Beris; and our agent, Jim Levine.

  Notes

  INTRODUCTION: CADILLACS, COMMUNISTS, AND PINK BUBBLE GUM

  The opening quote comes from Bertrand Russell’s 1950 book Unpopular Essays.

  For information on Elvis’s various Cadillacs, see “Elvis’s Cadillacs” (http://elviscadillacs.tripod.com). Elvis spent $100,000 on the custom Cadillac in 1960, which is the equivalent of spending $785,400 today. It was equipped with various other luxury features besides the diamond-dusted paint job and gold-plated hubcaps, including a refrigerator and a ten-disk record changer (there were no CDs back then).

  According to d’Estries (2012), J. K. Rowling had given away $160 million in charitable donations by 2012. The $15 million check was written to a multiple sclerosis treatment center at the University of Edinburgh (D’Zurilla 2010). Her mother had died at age forty-five from complications related to multiple sclerosis.

  Besides being husband to 365 wives, Rajinder Singh
was the first man in India to own a car or airplane; he was also an international polo champion. One of his many wives was an Irish-born British subject, which caused quite a stir in Britain in the 1890s (see Collins and LaPierre [1975] and Wikipedia, “Rajinder Singh”).

  For more on Ray Otero, see Feuer (2008).

  The Rational Animal

  For a more academic treatment of the contrast between our position and earlier economic models, see Kenrick et al. (2009) and Kenrick et al. (2012).

  CHAPTER 1: RATIONALITY, IRRATIONALITY, AND THE DEAD KENNEDYS

  For more on Joe Kennedy and his family, see Goodwin (1987) and Collier and Horowitz (1984). The Kennedy Curse was written by Edward Klein (2003).

  Rational Man: People as Econs

  For a basic introduction to the assumptions of classic rational economics, see any introductory economics textbook, such as Bronfenbrenner, Sichel, and Gardner (1990). As David Friedman notes, economics “starts from the assumption that individuals have objectives and tend to choose the correct way to achieve them” (1996, 3). In his classic work on economic rationality, John Stuart Mill proposed that a human being could be arbitrarily defined as “a being who inevitably does that by which he may obtain the greatest amount of necessaries, conveniences, and luxuries, with the smallest quantity of labour and physical self-denial with which they can be obtained” (1836/1874). For an entertaining application of the assumption that all our choices reflect rational decisions, see Levitt and Dubner’s Freakonomics (2005).

  Irrational Man: People as Morons

  See Grady (1999) for the argument that the curse of the Kennedys is due to their own reckless risk taking.

  For the scientific origins of loss aversion, see Kahneman and Tversky (1979) and Tversky and Kahneman (1981). To further explore the roots of behavioral economics, see Simon (1955, 1956).

  For accessible books on behavioral economics, see Ariely’s Predictably Irrational (2008), Thaler and Sunstein’s Nudge (2008), and Kahneman’s Thinking Fast and Slow (2011).

  Deep Rationality: Humans as Animals

  For evolutionary examinations of economics and decision making, see Aktipis and Kurzban (2004), Saad (2007), Gandolfi, Gandolfi, and Barash (2002), Cosmides and Tooby (1994), Kanazawa (2001), and Kenrick et al. (2009).

  For more general introductions to evolutionary psychology, see Buss (2005), Confer et al. (2010), Crawford and Krebs (2008), Dunbar and Barrett (2009), Gangestad and Simpson (2007), and Kenrick (2011).

  Loss Aversion in Monkeys and Men

  For the study of loss aversion in monkeys, see Lakshminarayanan, Chen, and Santos (2008).

  For more on how monkeys and humans share the same decision biases, see Lakshminarayanan, Chen, and Santos (2011).

  For more on human ancestral conditions, see Carroll (2009).

  For more on the evolution of loss aversion in humans, see Li et al. (2012) and Winterhalder (2007).

  Proximate Versus Ultimate Reasons for Behavior

  For the scientific origins of proximate and ultimate explanations in biology, see Tinbergen (1963).

  For a more detailed discussion of proximate and ultimate explanations in humans, see Kenrick, Griskevicius, et al. (2010) and Alcock (2013, ch. 10).

  The Subconscious Influence of the Ovulatory Cycle

  For the ovulation and spending study, see Durante et al. (2011).

  For the ovulation and stripping study, see Miller, Tybur, and Jordan (2007).

  The Kennedys and the Biology of Risk

  For the skateboarding study, see Ronay and von Hippel (2010).

  For studies showing that the presence of a woman increases men’s risk taking at card games, see Baker and Maner (2008, 2009).

  For the study showing men take more risks in the presence of an ovulating woman, see Miller and Maner (2011a).

  For the study showing that smelling T-shirts worn by ovulating women increases men’s testosterone levels, see Miller and Maner (2010).

  CHAPTER 2: THE SEVEN SUBSELVES

  For more on the life of Martin Luther King Jr., see Branch’s (1988) Pulitzer Prize–winning account of the civil rights leader and his place in history.

  Selves Within the Self

  For the classic The Three Faces of Eve, see Thigpen and Cleckley (1957).

  For good descriptions of the split-brain studies, see Gazzaniga (1985) and Sperry (1968).

  For the book on our evolved psychological systems or modules, see Kurzban (2010).

  For a more scientific analysis, see Barrett and Kurzban (2006).

  Primed for Persuasion

  For a general introduction to the idea of subselves, see Kenrick (2011).

  For the advertising study, see Griskevicius et al. (2009).

  How Many Subselves Are There?

  For more scientific detail on these subselves, see Kenrick, Li, and Butner (2003), Kenrick, Neuberg, et al. (2010), Kenrick, Griskevicius, et al. (2010), and Griskevicius and Kenrick (forthcoming).

  For the touching study at the University of Groningen, see Gazzola et al. (2012).

  Self-Protection Subself: The Night Watchman

  For more about the dangers of ancestral life, see Pinker (2011).

  For statistics on crime and violence in modern times, see Federal Bureau of Investigation (2011).

  For more on how a self-protection motive influences psychology and behavior, see Ackerman et al. (2006), Becker et al. (2007, 2010), Maner et al. (2005), Neuberg, Kenrick, and Schaller (2011), Schaller, Park, and Mueller (2003), and Ohman and Mineka (2001).

  For the car preferences study, see Griskevicius et al. (2006).

  Disease-Avoidance Subself: The Compulsive Hypochondriac

  For more on the behavioral immune system, see Schaller and Park (2011).

  For more on how a disease-avoidance motive influences psychology and behavior, see Ackerman et al. (2009), Miller and Maner (2011b), Mortensen et al. (2010), and Neuberg, Kenrick, and Schaller (2011).

  For the pregnancy study, see Navarrete, Fessler, and Eng (2007).

  Affiliation Subself: The Team Player

  For the importance of friendship in hunter-gatherers, see Hill and Hurtado (1996).

  For more on how the affiliation motive influences psychology and behavior, see Baumeister and Leary (1995), Maner, DeWall, et al. (2007), and Mead et al. (2011).

  Status Subself: The Go-Getter

  For more on the study of stress and dominance in baboons, see Sapolsky (2002).

  For more on the benefits of status on human health, see Marmot (2004).

  For more on status and luxury fever, see Frank (1999).

  For the idea of gaining status via dominance versus prestige, see Henrich and Gil-White (2001) and Cheng et al. (2013).

  For the effects of status motives on aggression, see Griskevicius, Tybur, et al. (2009).

  Mate-Acquisition Subself: The Swinging Single

  For more on how many human behaviors are related to mate acquisition, see Miller (2000).

  For some research comparing mating preferences in homosexuals and heterosexuals, see Bailey et al. (1994) and Kenrick et al. (1995). As discussed in Kenrick (2011), homosexuality raises some interesting puzzles from an evolutionary perspective, but male homosexual preferences paradoxically provide strong support for the two central ideas of this book: that the ultimate causes of our behavior are often not conscious and that the mind is organized in a modular fashion. If male homosexuals were acting “rationally” in a traditional sense, they would seek partners their own age or perhaps follow society’s standards for what constitutes an attractive man (older with high status). Instead, homosexual men are interested in young, physically attractive men, even when those men do not reciprocate their interest and even though these cues would be associated with women in the years of peak fertility rather than deemed stereotypically “masculine” characteristics.

  For the car preferences study, see Griskevicius et al. (2006).

  Mate-Retention Subself: The Good Spouse

  For
more on marriage and parenting in humans, see Geary (2000).

  For more on how mate-retention motives influence psychology and behavior, see Maner, Gailliot, et al. (2007) and Maner et al. (2009).

  Kin-Care Subself: The Nurturing Parent

  For more on parenting in traditional societies, see Geary (2000) and Hill and Hurtado (1996).

  For how much it costs to raise children, see Lino (2010).

  For more on how kin-care motives influence behavior, see Glocker et al. (2009) and Hrdy (1999).

  Remembering the Seven Subselves by Climbing the Developmental Pyramid

  For more on the developmental pyramid, see Kenrick, Griskevicius, et al. (2010).

  Reversing Loss Aversion

  For loss aversion as a specific numerical constant, see Thaler et al. (1997).

  For the study demonstrating how different fundamental motives reverse loss-aversion patterns, see Li et al. (2012).

  CHAPTER 3: HOME ECONOMICS VERSUS WALL STREET ECONOMICS

  For more on Walt Disney, the Walt Disney Company, and Michael Eisner, see Stewart (2005) and Thomas (1976, 1998).

  For more on the ideas presented in this chapter, see Kenrick, Sundie, and Kurzban (2008).