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

by Kenrick, Douglas T.

  Rather than showing that some people are inherently disposed to be conformists while others are inherently disposed to be unique, the study found that the same person will sometimes want to conform and at other times seek to be unique. When the situation elicited a person’s romantic subself, he or she craved uniqueness and avoided conformity. But when the situation elicited a person’s vigilant subself, he or she now craved conformity and actively avoided opportunities to be unique. From the perspective that you have a single unitary self—that you have only one personality—shifting between conformist and rebellious tendencies seems inconsistent and even hypocritical. But from a multiple-subselves perspective, the behavior is logical and consistent since, in different situations, you follow the deeply rational preferences of your different subselves.

  So given that there are multiple subselves living in your head, the next question is, how many?

  HOW MANY SUBSELVES ARE THERE?

  When people talk about evolutionary success, they often think only about survival and reproduction. But it is a gross oversimplification to assume that this is the whole story. Although surviving and reproducing are important challenges, humans had to surmount a number of distinct challenges to achieve evolutionary success. At a base level, our ancestors, like other animals, needed nourishment and shelter. But because humans are intensely social animals, they also faced a recurring set of crucial social evolutionary challenges. These evolutionary challenges include (1) evading physical harm, (2) avoiding disease, (3) making friends, (4) gaining status, (5) attracting a mate, (6) keeping that mate, and (7) caring for family.

  The humans who became our ancestors were those who protected themselves from enemies and predators, avoided infection and disease, got along with the other people in their tribe, and gained the respect of their fellow tribe members. They also successfully attracted a mate, established a partnership with that person (perhaps for the rest of their lives), and, if all went well, cared for their needy and relatively helpless offspring. Those humans who succeeded in solving these critical challenges enhanced their fitness and became our ancestors. Those who were less successful at solving these challenges failed to become anyone’s ancestors.

  Each evolutionary challenge is unique. The things a person does to successfully charm a date are different from the things one does to avoid a predator or care for a baby. Solving these different problems required our ancestors to make decisions in different—and sometimes completely incompatible—ways. What is effective when you are taking care of a child, for example, is different than what is effective when you are negotiating a business deal with distant acquaintances.

  The evolutionary result of our ancestors’ continually having to solve different problems is that the mind has different psychological systems for meeting each challenge. Just as it is more efficient to have different brain systems for analyzing color, sound, and taste, it is more efficient to have different psychological systems for attracting a mate, evading physical harm, and managing each of the other challenges.

  You can think of these different psychological systems as our subselves, where each is an executive vice president in charge of reaching a different evolutionary goal. Depending on which evolutionary goal is currently on your mind, consciously or subconsciously, a different subself will guide your decisions.

  To understand how the different subselves work, think of the brain as analogous to a computer. Like a computer, your brain receives input and produces output. Someone pressing a button or shouting a voice command generates input for a computer. Your senses—what you see, hear, touch, smell, and feel—provide the input for your brain. The critical part is what happens after the input arrives. For computers, pressing a particular button on a keypad will lead to a different output, depending on which software program is currently running. For example, pressing the button with the equal sign is going to produce a different result if you do it in Word versus in Excel. Word will show you an “=“ character; Excel will presume that you’re beginning to type in a mathematical formula.

  Computers have different software programs specialized to solve different challenges, such as the different tasks that arise at the office. For instance, your computer solves the challenges of writing documents, creating numerical spreadsheets, and designing slideshow presentations with different software programs (such as Word, Excel, and PowerPoint). Each software program is designed to solve a specific problem. Just as computers have different software programs to solve challenges faced at the office, the brain has different programs—the subselves—to solve the social challenges perennially faced by our ancestors. At any given point, your brain is running a different subself program, depending on whether you’re consciously or subconsciously trying to make a friend, seduce a date, impress your boss, avoid an aggressive panhandler on a dark street, or teach your child how to read.

  Just as a computer will process the same input differently depending on which software program is currently running, the brain will process the same input (a pat on the arm or an ad for a unique museum) differently depending on which subself is currently activated. For example, researchers at the University of Groningen observed activity in men’s brains when the men believed they were being touched either by an attractive female research assistant or by a male. Even though it was, in reality, always the same person doing the touching, different areas of the brain lit up when men thought a woman was touching them versus a man.

  The notion that the brain has different programs for managing different evolutionary goals has vast implications for how people make decisions. Not only will the subselves determine how people interpret the same information, but what a person likes, dislikes, and chooses will depend on which subself is currently running the show.

  MEET THE SUBSELVES

  Let’s meet each of our seven subselves. It might be tempting to think of the subselves as seven crazy dwarfs living inside your head. But instead, think of them as like a council of ancestral elders, with a different wise man or woman in charge of a specific evolutionary problem. Each elder has hundreds of thousands of years of experience—the accumulated wisdom of our ancestors—with successfully solving their assigned problem. So when you confront an important decision in the real world, your mind’s council wisely defers to the elder most evolutionarily adept at handling the situation. To see how each subself might deal with a given situation, let’s consider how each subself thinks, what triggers it to take charge, and the nature of the specific evolutionary challenge it confronts.

  Self-Protection Subself: The Night Watchman

  Although human beings can be helpful to others, they have always posed a danger to one another as well. Criminologists examining skull fragments from earlier human societies and anthropologists studying other cultures around the globe have discovered that homicide is not something invented in modern American society. On the contrary, our ancestors lived in groups with homicide rates that make Detroit or inner-city Los Angeles look tame by comparison. And even when the bad guys weren’t out to kill you, they often tried to steal your belongings, carry off your spouse or child, or burn down your village. Our ancestors had to successfully avoid threats posed by other predatory individuals.

  Threats of violence have hardly disappeared in the modern world. In the United States in 2008, there were over 16,000 reported murders and 830,000 aggravated assaults. And every day the news highlights yet another story of mass violence flaring up in yet another spot around the world. Everyday citizens (as well as gangsters and soldiers) go to great lengths to try to insulate themselves from such violence by investing in motion sensors, infrared detectors, guard dogs, and burglar alarms for their homes—not to mention paying hundreds of dollars in annual fees to have those systems monitored day and night. The wealthier live in gated communities and hire night watchmen; the less well-off invest in multiple locks for their doors and bars for their windows.

  Some people take a more active role in their self-defense, buying firearms that
range from the smaller-scale Glock 17C pistol with night sites ($542 plus shipping, in case you’re wondering) to a Barrett .50-caliber semiautomatic sniper rifle (available online for $11,699, complete with ten-round magazine, scope, and monopod). Though you may not have invested in your own firearms, you have, if you pay taxes, likely bought a few for the national military. The 2011 US budget included $60 billion for “protection” and another $964 billion for “defense.” With a population of 311 million people, that averages out to $3,294.60 spent by every man, woman, and child for government protection. That does not include the additional taxes you pay to support your local police, incidentally.

  Along with our colleagues, we’ve conducted a great deal of research on the self-protection subself. We find that your paranoid inner self can be primed not only by real or perceived physical danger but also by angry expressions on the faces of strangers, thoughts about members of other races and religions, scary movies, or the local evening news broadcast, which often starts with a gruesome crime. And speaking of the night-watchman aspect, simply being in a dark room can activate your self-protection subself.

  In the advertising study mentioned earlier, the self-protection subself motivated people to want to blend in with the crowd, and it led them to be particularly swayed by the opinions of others. In another study, we asked people whether they preferred a Mercedes-Benz or BMW. When the self-protection subself was activated, people chose the same brand that the majority of others preferred, regardless of which brand it was. If they learned that most other people preferred the Beamer, that’s what they wanted. If others liked the Benz, then the Benz was their top choice.

  Activating our inner night watchman makes us vigilant. It leads us to ask questions like, Is that band of nasty-looking guys who just walked over the hill going to steal something from me or burn down my hut? In studies conducted with Jon Maner, Vaughn Becker, and some of our other colleagues, we have found that activating the self-protection subself leads people to see men from other groups as angry, even when their expressions are perfectly neutral. This natural proclivity toward vigilance and paranoia inclines people to invest resources to avoid weakness or vulnerability, while placing high value on attaining strength or associating themselves with a powerful numerical majority. Above all, the self-protection subself wants to be safe from any potential physical danger.

  Disease-Avoidance Subself: The Compulsive Hypochondriac

  Biologists estimate that infectious diseases carried by other humans played a critical role in human evolution. In the 1300s, the bubonic plague killed up to 50 percent of the populations of Europe, Asia, and Africa. Two centuries later, descendants of those Europeans who survived the plague traveled to the Americas, carrying along diseases such as smallpox, measles, and typhoid, which killed over 75 percent of the population of Mexico. More recently, the 1918 Spanish flu killed between 40 and 100 million people worldwide.

  Modern humans have developed technologies to control several diseases and to limit their spread—from smearing sanitary wipes over the handles of supermarket carts to pasteurizing milk and sterilizing medical implements, for example. But beware! All those people you pass on the street are transporting contagious and sometimes virulent microorganisms, lurking in wait for any moment of contact, which could provide an opportunity for those potentially life-threatening microbes to jump from that stranger onto you. The World Health Organization estimates that every year, infectious diseases, including influenza, tuberculosis, and AIDS, take the lives of 15 million people (that’s more than the total population of every man, woman, and child living in New York City; Boston; Philadelphia; Washington, DC; Chicago; Miami; and Seattle combined).

  One result of this ever-present threat has been the evolution of a highly sophisticated biological immune system—an array of bodily defenses designed to defend against the threat of disease. Another is the evolution of our disease-avoidance subself, or what psychologist Mark Schaller calls a “behavioral immune system”—a set of prophylactic psychological mechanisms designed to help us avoid infection in the first place.

  The disease-avoidance subself is activated by things like the sound of other people sneezing and coughing, the sight of skin lesions, and foul smells. This subself can even be primed by thinking about people from exotic faraway places such as Sri Lanka and Ethiopia as opposed to Hawaii or London. This makes some sense given that we are unlikely to have resistance to exotic diseases carried by people from those exotic places, any of whom might be an unwitting smuggler of some disease that could be fatal to us.

  When our inner compulsive hypochondriac has been primed, we act in ways designed to thwart pathogen transmission. Because other humans can carry diseases, this subself leads people to avoid contact by becoming more introverted and less tolerant of foreigners—folks from exotic places that might harbor even more exotic microbes. Research by Carlos Navarrete and Dan Fessler finds that women become particularly afraid of foreigners in the first trimester of pregnancy, the precise time when developing fetuses are most susceptible to serious problems if mom catches a disease. Above all, the disease-avoidance subself wants to be safe from anything associated with pathogens.

  Affiliation Subself: The Team Player

  Other people bring threats and disease, but they are also the source of the most important benefits in our lives. To be evolutionarily successful, our ancient ancestors needed to get along with other folks. Anthropologists who study hunter-gatherer groups (of the sort our ancestors evolved in) have found that making friends and forming alliances are essential to evolutionary success. For example, anthropologists Kim Hill and Magdalena Hurtado went deep into the rain forests of South America to study a group called the Aché, carefully recording which members of the tribe shared food with one another. They found that in such groups friends provide a natural insurance policy against starvation. Without refrigeration, one family cannot eat a whole pig, but a group of families sharing their catches can pool their risk and stand a better chance of making it through tough times.

  Friends don’t just share food; they also teach one another valuable skills, like how to fish, cook, and build a hut. Friends team up to move things that are too big for one person to carry, and they provide safety in numbers when the bad guys come around.

  The need for friends and allies didn’t end when our predecessors moved out of the bush and took up residence in the big city. We modern urbanites still invest heavily in building and maintaining our friendships. As we write this book, for example, Facebook has already passed 1 billion active users, who devote endless hours to passing on clever newspaper articles or new songs, reading about their friends’ children’s accomplishments, and choosing the correct comment (“Oh, how cute! You must be so proud, Jenny!”). And let’s not forget the time, energy, and money invested in iPhones and other devices people use to text friends while driving home in heavy traffic or to share a picture of their cat’s lunch with their 300 closest companions. The majority of our graduate students spend over $1,000 a year on their iPhones, despite having annual incomes in the $15,000 range. Even in the modern era, friends provide more than just digital support. We need them when we want to move a couch, when our car breaks down and we need a ride, if we’d like a place to crash while driving across the country, or if we could use some advice about how to raise a child.

  The affiliation subself is triggered by anything that cues friendship, like when your old college roommate sends a Christmas card, when you’re thinking about inviting a neighbor for dinner, or when your coworker picks up the tab for lunch. This subself is also active when friendships are threatened. If you’re feeling lonely, rejected, or exploited, the affiliation subself takes the helm. When the inner team player is primed, people spend more money on products that connect them with other people (like a wristband sporting their university logo) rather than on products normally consumed alone (like a box of Oreo cookies). This subself also spurs us to do things that we might not like but that a friend enjoys, like
smiling happily through a painfully silly movie that our friend thinks is brilliant (“Umm, no, I can’t understand why the critics panned Junior either. What could be more hilarious than Arnold Schwarzenegger playing a pregnant gynecologist?”). Above all, the affiliation subself wants to be liked and treated as a friend.

  Status Subself: The Go-Getter

  Besides dealing with the challenge of getting along with their fellow group members, our ancestors also needed to manage the very different challenge of gaining and maintaining status within their groups. Getting some respect from others has always brought a host of benefits, and this arrangement didn’t start with human beings. Dominant baboons get first crack at food and the best spot at the watering hole, and dominant male chimps get to mate with the most desirable females. Stanford biologist Robert Sapolsky, who followed the same baboon troop for several years, found that high-status animals show fewer signs of physiological stress than their group mates at the bottom of the totem pole.

  The benefits of status continue to apply in the modern world, where the boss gets the big corner office, a special parking spot for his Lexus, a first-class seat on the plane, and an expense account to dine in the best restaurants. As a consequence, people go to great lengths to impress others with their status, shelling out inordinate amounts of money for Gucci shoes, Armani suits, Rolex watches, BMWs, and $500 dinners at The French Laundry. What economist Robert Frank calls “luxury fever” infects purchases at all levels, including $300 shoes, $10,000 outdoor grills, $20,000 Sub-Zero freezers, and $2 million McMansions, not to mention personal jets and supersized yachts. Back in the middle-class suburbs, teenagers, who are in a critical phase of establishing their position in the status hierarchy, often pressure their parents to pay more than twice as much as necessary for shoes, pants, and backpacks so as not to lose face by sporting last year’s fashions.