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

by Kenrick, Douglas T.

  In fact, for elephants, humans, and any animal that gives birth to relatively helpless babies, reproductive effort is about much more than just copulation. Successful reproduction is subdivided into two very different tasks: mating effort (energy resources spent on things like competing for status, attracting a mate, and copulating) and parenting effort (energy resources spent to ensure that their offspring are capable of surviving and reproducing on their own). Human life histories, like those of elephants, involve a lot of growing, a bit of mating, and then a lot of parenting.

  THE THREE STAGES

  By looking at ourselves through the lens of life history theory, we can see that, like other animals, we follow a predictable developmental sequence across the lifespan. Like other critters, our life histories can be divided into three stages, each characterized predominately by one type of effort: somatic effort, mating effort, and parenting effort. These stages help explain how our priorities and psychologies change across the lifespan. In fact, each of our specific subselves is more likely than others to direct our choices during some life stages. Recall the developmental pyramid from Chapter 2 (see Figure 2.1 for a reminder). That pyramid depicts how, as we mature, each of our subselves builds upon the ones that came before.

  All animals must first survive and grow before they can reproduce. The first life stage of somatic effort provides a necessary developmental foundation before mating effort can unfold. During this initial stage children develop physically, build up their immune systems, and start learning social skills that enable them to form a network of friends. During the somatic stage, the self-protection and disease-avoidance subselves come online. Toddlers are particularly wary of outsiders (stranger danger peaks between ages two and three), and they are averse to ingesting novel foods, often preferring to eat the same food day after day after day (the thousandth peanut butter sandwich is welcomed with a smile, but those walnuts and avocados—positively yucky!). Children become concerned with making friends only much later, which is when the affiliation subself comes online to usher in the second life history stage.

  If you have raised a teenage son or daughter, or if you just recall your own high school years, you might remember that during the second stage, involving mating effort, things get testy. For both men and women, mating effort peaks in young adulthood, the period from our mid-teens through the late twenties. After those innocent and asexual elementary school years, mating effort suddenly starts to monopolize an inordinate amount of a high schooler’s time and effort. Am I popular or good-looking enough? Are other kids impressed with my status or are they looking down on me? Do I fit in with the in crowd? Do I stand out enough to draw attention? And the ultimate question: Can I land a date with that charming and attractive kid who sits next to me in history class?

  Across the animal kingdom, mating effort is associated with rampant aggression and conspicuous showing off. The same is true across human societies. People at this age get the largest rush of adrenaline from doing things like jumping off bridges and spelunking into bottomless holes. Young adults are most likely to experiment with drugs, intoxicants, and risky sexual behavior. It’s no coincidence that car crashes are the leading cause of death for American teenagers. Not only are teens less likely to be wearing their seat belts, but they are also more likely to be overconfident about their driving abilities, to be intoxicated, and to be driving around with more passengers—the ones they might want to impress with their recklessness.

  The vigor of our mating effort is directly related to the amount of testosterone flowing through our bodies, which rises substantially in the mid-teens and peaks in our twenties. Testosterone stokes the flames of competition, rebellion, and lust. When men and women are injected with testosterone, they become more aggressive and more interested in sex. In one study of 4,462 military veterans, those with high testosterone levels had been in more trouble with the law, been more violent, and racked up an unusually large number of sexual partners.

  The pubertal surge of testosterone marks the emergence of the mate-acquisition and status subselves, which dominate our behavior throughout most of the second life stage. The testosterone rushing through our veins also suppresses the self-protection and disease-avoidance subselves that were highly active when we were younger. After all, it’s difficult to take wild risks and impress others when you are worried about your health and physical safety.

  The decreased concern for safety can make the mating stage especially dangerous. Examining homicide patterns from Canada to Kenya and from medieval Europeans to the !Kung San of the Kalahari Desert, evolutionary psychologists Martin Daly and Margo Wilson found that killers everywhere are disproportionately young adults. Compared to a more mature fellow in his early forties, a young man in his early twenties is 400 percent more likely to kill another man.

  And what’s the main motive for all this violence? The single most common cause of murder, accounting for up to 37 percent of all homicides, is what’s officially termed a trivial altercation. Police call such altercations trivial because they begin over relatively petty issues, such as a few words of insult, a curse, or one person bumping into another. As one Dallas homicide detective put it, “Murders result from little ol’ arguments about nothing at all. Tempers flare. A fight starts, and somebody gets stabbed or shot. I’ve worked on cases where the principals had been arguing over a 10 cent record on a jukebox, or over a one dollar gambling debt from a dice game.” Daly and Wilson pointed out that most violence has to do with status and mates—especially the lack thereof. In one study of Detroit homicides, 41 percent of the perpetrators were unemployed, and 73 percent were unmarried.

  If a person survives the mating-effort stage (and for some young men, the homicide statistics tell us that this is a real if), he or she is likely to reach the third life stage, involving parenting effort. This final stage is associated with forming a long-term bond with another person, usually a marriage partner. This relationship creates a foundation for producing and successfully raising offspring. Although there is no official timetable for the beginning of the parenting stage, the average age for becoming a first-time parent in the United States is twenty-five for mothers and twenty-seven for fathers, although people in some other countries start families later (average age of first-time mothers is 29.2 in Japan and 29.5 in England, for example). Most people are in the parenting stage by the time they hit forty. And this third phase lasts longer than just the years spent raising your own kids—parenting effort for human beings also includes grandparenting.

  The parenting stage brings about decreases in aggression and competitiveness. In one study, researchers observed amateur hockey players in Canada, comparing the games played by younger, unmarried men in their twenties with those played by older, married men in their thirties. The older players were fully three times less aggressive than the younger players. And when the older guys bumped or yelled at one another, most of the incidents were humorous—just minor teasing and joking around. For the younger men, there was nothing funny about the competition. The younger players not only got angry more easily but were four times more likely to display what the researchers called “cold hostility”—intentionally pushing, shoving, or hitting another player with no hint of a smile or an apology.

  As men and women hit their thirties, testosterone levels start to decline. This hormonal decrease doesn’t just follow a preset biological timer; it depends on whether you’ve entered the parenting-effort stage. Testosterone levels go down when a person gets married, and they decrease even further after the birth of a child. Philippine women who have had a child, for instance, have 30 percent less testosterone than women of the same age and socioeconomic status who don’t have children. Likewise, North American men’s testosterone levels drop when they get married, and then drop again when they have a child.

  The parenting stage is when our mate-retention and kin-care subselves take center stage. Interacting with a long-term partner and a new baby continually activates the subselves de
voted to being a good spouse and parent. Meanwhile, the neglected self-protection and disease-avoidance subselves experience a bit of a resurgence, since we now need to stay alive and healthy to raise our offspring and to protect them from various threats. By the time people are married with children, it’s just not as fun to go jumping off bridges or running red lights, and they feel less need to explode violently over an insult or get hostile during an athletic game.

  THE AGE OF ENTREPRENEURISM

  Our shifting priorities through the different life stages have important consequences for how we approach financial decisions at different points. Thanks to high testosterone levels in young adulthood, the mating stage leads people to have the greatest appetite for risk, adventure, and gambling.

  Consider the ages of the players in the World Series of Poker—a giant tournament that takes place in Las Vegas each year. Of the roughly eight thousand entrants, who each fork over a $10,000 entry fee, the average age is about twenty-five. Each year, savvy older poker veterans such as Phil “The Poker Brat” Hellmuth notoriously complain that today’s young upstarts are playing the game with reckless abandon, bluffing and going “all in” when it’s completely irrational to do so. But this kind of brazen play appears to have some payoffs. The last five people to win the grand prize (worth around $9 million) have been twenty-two, twenty-one, twenty-three, twenty-two, and twenty-four. Hellmuth, who is now nearing his fifties and is married with two kids, hasn’t won the tournament himself since the ripe old age of twenty-four.

  Age and testosterone don’t affect just bets in Vegas. We can witness their effects in the daily activities of the whole financial sector. One British study followed futures traders at the London stock exchange (who were on average 27.6 years old), measuring their testosterone levels every morning for several weeks. On the days when the traders’ testosterone levels were higher than average, they made eight times more profit than on the days when their testosterone count was hovering at the average level. The researchers attribute this enhanced success to the fact that testosterone increases persistence and fearlessness in the face of novelty.

  After this study came out, clinics in New York City reported a rise in treatment for testosterone deficiency. Upper West Side doctor Lionel Bissoon, who performs hormone-replacement therapy, believes that testosterone is becoming the drug of choice for Wall Street traders seeking an edge over their professional rivals—90 percent of his patients are men in the finance industry in their thirties and forties who hope that testosterone boosters will help them perform better at work and enable them to put in longer hours. “If you’re going to be trading on Wall Street or dealing with large sums of money, you had better be confident,” Dr. Bissoon explains. “The man who is wishy-washy is not going to be successful.”

  Given that testosterone peaks in the early twenties, age might be a particularly important factor in entering careers that require immense risk taking, such as entrepreneurial ones. MC Hammer was twenty-two when he took a big risk by borrowing $40,000 from former Oakland A’s players Mike Davis and Dwayne Murphy to start a record label called Bust It Productions. Selling records from the trunk of his car and marketing himself relentlessly, CEO Hammer soon recorded his own album, Feel My Power, on which he began aggressively waging war against rival rappers such as Doug E. Fresh and LL Cool J by calling them out in his songs and declaring himself “second to none.”

  And when it comes to the world of Internet tycoons, at least one venture capitalist thinks that “Internet entrepreneurs are like pro basketball players. They peak at 25. By 30 they’re usually done.” Larry Page and Sergey Brin were both twenty-five when they founded Google in 1998. Bill Gates was twenty-one when he founded Microsoft, Mark Zuckerberg was twenty-one when he started Facebook, and Steve Jobs was twenty-one when he started Apple with his twenty-five-year-old buddy Steve Wozniak. Apple was initially supposed to be a three-man operation with Jobs, Wozniak, and Ronald Wayne each owning a significant chunk of the company. We met Wayne earlier in Chapter 4 on smoke detectors in the mind; he’s the guy who would have had $2.6 billion today if he hadn’t decided to pull out of the deal after two weeks, explaining that he didn’t have the stomach for such a risky entrepreneurial venture. Might age have had something to do with his cold feet? Unlike the youthful Jobs and Wozniak, Wayne was forty-two at the time.

  The testosterone-juiced young are not just willing to stomach more risks; they are also more aggressive in their dealings with other businesspeople. One study, examining 357 mergers and acquisitions deals, found that young CEOs were more combative, more likely to try to acquire other companies, and more likely to resist being acquired themselves. Young moguls seek to protect their turf fiercely, while aggressively expanding their empire. This has some powerful implications for negotiation.

  Imagine that a man must share $40 with you, so he makes you an offer. If you accept the offer, each of you gets to take home the agreed-on amount. But if you reject the offer, neither of you gets anything. If the man offered you only $5 out of $40, would you take it?

  When researchers examined this exact question, they found that men’s responses depended on their testosterone level. For men with below-average testosterone, 93 percent accepted the offer, happily taking $5 for themselves while letting the other man have $35. But of the men with above-average testosterone, almost half—45 percent—rejected the offer, choosing to take $0 rather than lose face by accepting a raw deal. And of the men in the study with the highest level of testosterone, fully 71 percent outright rejected the low offer.

  Because the young are more restless and prone to risk taking, they are more willing to test their luck in risky professions such as fishing in the unforgiving, icy waters of Alaska, logging giant trees with chain-saws, or starting their own business. But while younger individuals are more likely to test their luck, does this always make them better entrepreneurs? The answer appears to be no. Because young adults are more likely to be blinded by myopic optimism and naïve enough to bet everything on one hand, a few will succeed. But many more will fail. A study of 549 successful entrepreneurs found that those who succeeded in their ventures were, on average, older and more experienced when they started the company that ultimately went on to be successful. Of course, successes are often preceded by many failures from risky ventures undertaken when people were younger. While older individuals might be wiser when they do take risks, they are less likely to enter into risky ventures in the first place.

  FAST VERSUS SLOW STRATEGIES

  Imagine you’re one of the five-year-old children who showed up for a now classic study at Stanford University. As you wait by yourself in a room free of distractions, you are offered a tasty marshmallow, planted temptingly on the table right in front of you. You are told it’s alright to munch the tasty treat if you really want to, but if you can wait for a little while without giving in to temptation, you will be rewarded with two marshmallows. What would you do?

  After the researcher left the room in the study, each child was observed through a one-way mirror. Whereas some of the kids gobbled the marshmallow right away, others tried to resist. The scientists observed that some of the latter kids would “cover their eyes with their hands or turn around so that they [couldn’t] see the tray.” A few began kicking the desk or tugging on their pigtails. And one even started to “stroke the marshmallow as if it were a tiny stuffed animal.”

  The marshmallow study tested people’s ability to delay gratification. A decade later, when the children from the study had grown into adolescents, those who had resisted eating the marshmallow as five-year-olds were more competent teenagers as judged by their parents and teachers. And a few years later, those same individuals scored higher on their SAT exams. The message is simple: impulsiveness bad; delayed gratification good.

  But is delaying gratification always a good thing? And might acting impulsively sometimes be smarter? Life history theory suggests that there is more to the marshmallow test than meets the eye. So far we have tal
ked about how people’s general priorities change across the lifespan. But life history theory emphasizes that there are important differences among people who are pursuing different strategies. Although just about everyone goes through the mating stage, for example, some people in this phase have an eye on tomorrow, while others seek to live for today. And as we’ll discover, it turns out that impulsivity is sometimes the best strategy.

  HIGH RISK, NO REWARD

  Ray Otero works as a building superintendent at 106 East Eighty-fifth Street in New York City. A former car mechanic with a happy-go-lucky disposition, Otero has an unusual investment strategy. He “invests” $500 to $700 every week in the lottery. He plays the game in shifts, placing one bet in the morning at eleven o’clock and another in the midafternoon. His bets range from $10 to $20 on a scratch-off game or on the daily numbers, and he picks his digits from the license plates of parked or passing cars.

  Otero is fully committed to his investment strategy—so much so that he spends a whopping $30,000 a year on the lottery! In 2008, Otero’s buddy Richie Randazzo, the doorman for the building across the street, won $5 million in the Set for Life scratch-off game. The forty-four-year-old Randazzo, now set for life, immediately started dating a leggy, twenty-three-year-old Swedish model (who was later charged with promoting prostitution at Big Daddy Lou’s Hot Lap Dance Club). But Otero himself has thus far failed to recoup his staggering investment. He has won only three times, earning $1,000 on a scratch-and-win and pulling in $2,000 on the Pick Five twice. But all of it was reinvested. “No matter how much I get,” he says, “I always spend it back.”