The Rational Animal: How Evolution Made Us Smarter Than We Think (5 page)

With the attractive young woman looking on, each skateboarder demonstrated his tricks a few more times, then donated a sample of saliva to the researchers, who later analyzed it for the amount of the hormone testosterone.

The researchers found that the beautiful woman caused the young skaters to throw caution to the wind.
Taking more chances led to a lot more crash landings, but it also led to more successes on the difficult tricks—the kind of daring stunts that a young woman who enjoys the punk musical stylings of the Dead Kennedys might find impressive.
But this boost in riskiness was accompanied by two additional findings that reveal something deeper about the evolutionary biology of risk.

First, the guys’ testosterone levels automatically shot up when the beautiful woman was watching.
Having more testosterone flowing through their veins tends to inspire men to move faster and more recklessly.
In fact, the boost in risk taking was found primarily among those fellows whose testosterone levels zoomed up the most.

Second, the researchers gave the men a test tapping the functioning of the ventral medial prefrontal cortex, an area of the brain that cranks into high gear when we need to assess rewards and punishments.
When the beautiful woman was watching, guys did worse on the test, suggesting that boosts in testosterone may have shut down this brain area, normally involved in making careful judgments.
These findings make evolutionary sense to the extent that successfully showing off to a beautiful woman enhances a man’s chances of attracting her as a mate.
To show off, though, a bloke needs to be willing to throw caution to the wind—to take his foot off the brakes and hit the gas—and take some otherwise foolish risks.

The skateboarders didn’t consciously decide to take more risks when the woman was watching.
Instead, unconscious ancestral mechanisms made this decision for them, by flooding their bodies with testosterone specifically when a woman could observe their behavior.

Evolution has honed male biology to be attuned to reproductive opportunities, like the presence of an attractive woman.
From the perspective of a fellow’s genes, though, it would be especially nice if, before he risked his neck, he could somehow ascertain that the woman watching him was currently capable of becoming pregnant.
But is that even possible?

In a laboratory at Florida State University, psychologists Saul Miller and Jon Maner investigated this precise possibility by observing men as they played a game of blackjack.
In case you don’t hang out in casinos, blackjack is a card game in which you can choose to play it safe (by declining any new cards once you get to sixteen or higher) or to take risks (by deciding to take a new card and risk the possibility of “busting” by going over twenty-one).
As the men played blackjack, the researchers had a young woman observe them.

Just like the Aussie skateboarders, the Floridian fellows took more risks when the woman was watching.
But this study raised the stakes.
Over the course of the experiment, the researchers kept track of where the female research assistant was in her ovulatory cycle.
Although she had been carefully instructed to dress and act identically every single day, her presence had a different effect on men’s play on the days she was ovulating.
When she was most fertile, the fellows took the most risks.

How did the men know she was ovulating?
They didn’t, at least not in any way they could consciously identify.
But their bodies knew.
In a follow-up study, the researchers found that merely exposing men to the subtle scent of an ovulating woman’s T-shirt instantly caused men’s testosterone levels to shoot up.

Armed with an understanding of the intimate connections between men’s risk-taking biology and reproductive success, let’s return to the saga of the Kennedys.
The family’s penchant for risk occasionally led to bad judgments, unfortunate outcomes, and even a few dead Kennedys.
Risk always involves trade-offs.
Taking hazardous chances can lead to death, but it can also lead to payoffs like money and status.
At a deeper level, though, the Kennedy men’s risk taking paid off in the most valuable currency in the evolutionary realm—reproductive success.
Recall that women in all societies around the world are attracted to ambitious
men willing to take risks to become successful.
Although taking these kinds of risks led some of Joe Kennedy’s descendants to perish, his genes have flourished.
In the course of only a few generations, the genes of this one Irishman have thrived—producing twenty-nine grandchildren and over sixty great-grandchildren.
And as we noted before, those descendants themselves continue to live rich and successful, if occasionally risky, lives.

THE ULTIMATE QUESTION

So, are people rational or irrational?
If we look only at the surface, many of our choices appear rather foolish.
Most of us would choose to be the person in the movie-ticket line who lucked into $100 instead of the one who won $150 but didn’t win $1,000.
It’s not economically rational to say, “No thanks.
I prefer not to have an extra free fifty bucks.”
The many superficially worrisome tendencies of the human mind lead some of us to seriously doubt whether people are rational Econs and to consider instead that they are all dim-witted morons.

Well, we beg to differ.
Rather than Econs or morons, we are rational animals.
Yes, decision making is biased, and yes, individual decisions are sometimes rather moronic.
But underneath all those biases and misjudgments is an exceptionally wise ancestral system of decision making.
To understand how people make decisions, we must first ask why the brain evolved to make the particular choices that it does.
By connecting the story of human behavior with that of the rest of the animal kingdom, we come to see that our brains are designed to make choices in ways that enhanced our ancestors’ fitness.

B
UT THERE’S
a twist in the plot!
Just because evolutionary forces guide our behavior does not mean that you or I or Joe Kennedy’s newest great-grandson is driven to achieve just one single evolutionary goal of “maximizing fitness.”
Just as it is too simple to say that people seek utility, it is too simple to say that people seek fitness.
Instead, as we discuss next, human decision making is designed to achieve a set of very different evolutionary goals.
In investigating how people meet these evolutionary goals, scientists have discovered something
important: solutions to these different problems often require us to make decisions in different—and sometimes completely incompatible—ways.
We are, in fact, inconsistent by design.
To see why this has profound implications for your decisions, let’s make a stop in Alabama and take a look at several puzzling decisions made by Martin Luther King Jr.

2

The Seven Subselves

O
N
S
EPTEMBER
28, 1962, Martin Luther King Jr.
was sitting peacefully on a convention stage in Birmingham, Alabama, when a man in the audience casually walked onstage and approached him.
Suddenly, the man began punching Dr.
King in the face.
King was knocked over by the first blow, but even as the civil rights leader fell, his attacker continued throwing a brutal barrage of punches.
Although King had been advocating nonviolent protests against racial discrimination, no one would have blamed him if he had gotten violently angry at his assailant, a white supremacist later revealed to be on a mission from the American Nazi Party.
Instead, King chose a different course of action.
He stood back up, gazed into his attacker’s face with a look of transcendent calm, and dropped his arms defenselessly, “like a newborn baby,” according to one observer.
As others jumped to his defense, King pleaded with them, “Don’t touch him.
Don’t touch him.
We have to pray for him.”

This incident is one of many that demonstrated King’s commitment to moral principles.
Ordained as a Baptist minister, Reverend King devoted himself to embodying and promoting the ideals of decency, integrity, and virtue.
His commitment to nonviolence was steadfast and consistent, extending well beyond issues of civil rights for African Americans.
He spoke out against the war in Vietnam, for example, even though it cost him the support of powerful allies such as
President Lyndon Johnson.
On other occasions, his commitment to nonviolent protests against civil rights landed him in jail.

Yet Dr.
King’s unwavering commitment to moral principles did not extend to the realm of extramarital affairs.
King’s friend and fellow civil rights leader Ralph Abernathy admitted that the iconic religious leader, despite being a married man with four young children, was a “womanizer.”
Besides having an ongoing affair with a woman he saw frequently, King allegedly also engaged in numerous short-term liaisons with other women while he was traveling.
According to biographer David Garrow, King’s promiscuity caused him to feel extreme guilt.
But that guilt was not enough to alter his behavior.
When faced with temptations of the flesh, Dr.
King repeatedly put aside his higher moral values.

Did King’s moral lapses result from an occasional breakdown in the operation of the otherwise rational man inside his head?
Or might there be another explanation for his behavioral inconsistencies?
We argue that Martin Luther King Jr.
suffered from a common form of multiple personality disorder.
Even without reexamining the evidence from his biographies or consulting a single psychiatrist, we believe we can diagnose King as having at least seven personalities.

In fact, when we say King had a “common” form of multiple personality disorder, we are understating the case.
Multiple personalities are not just common; they are universal.
Without knowing a single thing about the particulars of your life, we argue that you also have at least seven personalities.
Although it feels as if there is just one single self inside your head, at a deeper evolutionary level, you have a multiplicity of selves.
And worse yet, each of these selves is like a little dictator who completely changes your priorities and preferences when he or she takes charge.
This is important because it means that the same person will make different choices depending on which self is currently at the helm.

SELVES WITHIN THE SELF

A famous clinical case study of multiple personality disorder was turned into the movie
The Three Faces of Eve
, in which the central character
switches between the timid and self-effacing “Eve White” and the dangerously fun-loving and flirtatious “Eve Black.”
The real-life character depicted in this movie was Chris Sizemore, whose psychiatrists claimed had not just three but twenty different personalities.
While the majority of people do not suffer from the clinical version of multiple personality disorder, each normal person does have multiple selves.

At first blush, it might seem shockingly counterintuitive to claim that there is not one single you running the show inside your head.
But an overwhelming body of scientific evidence supports the idea of multiple selves.
Some of the earliest research came from a classic series of studies on “split-brain” patients, conducted in the 1960s by Michael Gazzaniga and Roger W.
Sperry.
Gazzaniga and Sperry studied people whose left and right cerebral hemispheres had been surgically separated (as a treatment for epilepsy).
For these people the verbal left side of the brain could not communicate with the nonverbal right side.
If the researchers showed an image (a picture of a spoon, for example) to the subject’s verbal left brain (by flashing it into the right half of the visual field), the person was able to name it.
But if the same image was flashed into the left half of the visual field (thus appearing only to the nonverbal right brain), the person could point to a spoon to indicate that it was the object in the image, but was unable to name it.
This work, which became a cornerstone of modern neuroscience and eventually won a Nobel Prize, began to challenge the idea of a unified consciousness.
It showed that our conscious experiences can be very different depending on which part of the brain is currently active and processing incoming information.

In the intervening fifty years, many other findings—from human and animal neuropsychology, biology, and studies of learning and memory—have revealed that there is not one single executive system inside your head but a conglomeration of separate systems, running different subprograms to deal with different problems.
Reviewing the evidence in his book
Why Everyone (Else) Is a Hypocrite
, University of Pennsylvania psychologist Rob Kurzban points out that the mind’s different systems (or modules) sometimes disagree with each other, which can lead us to behave inconsistently.
This means that it’s not just Martin Luther King Jr.
who’s a hypocrite—you, your neighbors,
and the guy with the split brain pointing at a spoon are all hypocrites.
According to Kurzban, the nature of our divided mind suggests that there is no “I”; instead, each of us is a “we.”

Despite the mounting evidence for multiple selves, the idea that each one of us has a single unitary self remains intuitively compelling and widespread.
For rational economists, the number-crunching business whizzes we met in the last chapter, a cornerstone assumption about human behavior is that people have stable preferences.
If you choose to put cream and sugar in your coffee on Tuesday in Birmingham, Alabama, you are also likely to choose cream and sugar with your coffee in Memphis, Tennessee, on Wednesday.

This assumption about stable preferences is pervasive in business and psychology.
Advertisers, for instance, look to pitch particular products to matching market segments.
They don’t place ads for Harley-Davidson motorcycles in church periodicals.
Financial advisors categorize their clients according to various investment risk-tolerance profiles and avoid recommending highly risky and volatile stock opportunities to librarians.
Personnel officers try to match the right person for the right job and steer clear of placing artistic coffeehouse types in the accounting department.
In all of this, there is a presumption that a given consumer, investor, or job applicant will be the same tomorrow as today, the same in an hour as now, and the same in another building as in this one.