The Better Angels of Our Nature: Why Violence Has Declined (135 page)

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Authors: Steven Pinker

Tags: #Sociology, #Psychology, #Science, #Social History, #21st Century, #Crime, #Anthropology, #Amazon.com, #Retail, #Criminology

BOOK: The Better Angels of Our Nature: Why Violence Has Declined
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To make the case more than circumstantial, one would have to show that the psychologists’ conception of self-control (measured by people’s choice between smaller-sooner and larger-later rewards or by ratings of their own impulsiveness) match up with the criminologists’ conception of self-control (measured by actual outbreaks of violence). Mischel tested children in urban middle schools and in camps for troubled youth and found that the children who waited longer for larger piles of M&Ms were also less likely to get into fights and to pick on their playmates.
98
Many studies of teachers’ ratings have confirmed that the children who appear to them to be more impulsive are also the ones who are more aggressive.
99
A particularly informative study by the psychologists Avshalom Caspi and Terri Moffitt followed an entire cohort of children born in the New Zealand city of Dunedin from the year of their birth in 1972–73.
100
Three-year-old children who were rated as undercontrolled—that is, impulsive, restless, negativistic, distractible, and emotionally fluctuating—grew into twenty-one-year-olds who were far more likely to be convicted of a crime. (The study did not distinguish violent from nonviolent crimes, but later studies on the same sample showed that the two kinds of crime tend to go together.)
101
And one of the causes of their greater criminality may have been differences in their anticipation of the consequences of their behavior. In their answers to questionnaires, the less-controlled people gave lower odds that they would get arrested following a string of crimes, and that they would lose the respect of their friends and family if their illegal behavior came to light.
The trajectory of crime in adolescence and young adulthood is related to an increase in self-control, measured in a growing willingness to choose larger late rewards over smaller earlier ones. This change is partly driven by the physical maturation of the brain. The wiring of the prefrontal cortex is not complete until the third decade of life, with the lateral and polar regions developing last.
102
But self-control is not the whole story. If delinquency depended
only
on self-control, young teenagers should become less and less likely to get in trouble as they turn into older teenagers, which is not what happens. The reason is that violence depends not just on self-control but on the urges that self-control has to control.
103
Adolescence is also an age that sees the rise and fall of a motive called sensation-seeking, driven by activity in the Seeking system, which peaks at eighteen.
104
It also sees an increase in male-against-male competitiveness, driven by testosterone.
105
The rise in sensation-seeking and competitiveness can overtake the rise in self-control, making older adolescents and twenty-somethings more violent despite their blossoming frontal lobes. In the long run, self-control gains the upper hand when it is fortified by experience, which teaches adolescents that thrill-seeking and competitiveness have costs and that self-control has rewards. The arc of crime in adolescence is the outcome of these inner forces pushing and pulling in different directions.
106
Self-control, then, is a stable trait that differentiates one person from another, beginning in early childhood. No one has done the twin and adoption studies that would be needed to show that performance on standard tests of self-control, such as the marshmallow test or the adult equivalent, are heritable. But it’s a good bet that they are, because pretty much every psychological trait has turned out to be partly heritable.
107
Self-control is partly correlated with intelligence (with a coefficient of about 0.23 on a scale from–1 to 1), and the two traits depend on the same parts of the brain, though not exactly in the same way.
108
Intelligence itself is highly correlated with crime—duller people commit more violent crimes and are more likely to be the victims of a violent crime—and though we can’t rule out the possibility that the effect of self-control is really an effect of intelligence or vice versa, it’s likely that both traits contribute independently to nonviolence.
109
Another clue that self-control is heritable is that a syndrome marked by a shortage of self-control, attention deficit hyperactivity disorder (which is also linked with delinquency and crime), is among the most heritable of personality traits.
110
So far all the evidence that violence is released by a lack of self-control is correlational. It comes from the discovery that some people have less self-control than others, and that those people are likelier to misbehave, get angry, and commit more crimes. But the correlation doesn’t prove causation. Perhaps people with low self-control are more crime-prone because they are also less intelligent, or they come from worse environments, or they have some other across-the-board disadvantage. More important, a stable trait that differs from one person to another cannot explain the main thing we’re trying to explain: why rates of violence change over the course of history. To show that, we need to show that individual people, when they let up or clamp down on their self-control, get more or less violent as a result. And we must show that people and societies can cultivate the faculty of self-control over time and thereby drive down their rates of violence. Let’s see if we can find these missing links.
 
When a person fights an urge, it feels like a strenuous effort. Many of the idioms for self-control invoke the concept of force, such as
willpower
,
force of will, strength of will,
and
self-restraint
. The linguist Len Talmy has noticed that the language of self-control borrows from the language of force dynamics, as if self-control were a homunculus that physically impinged on a stubborn antagonist inside the skull.
111
We use the same construction in
Sally forced the door to open
and
Sally forced herself to go to work
; in
Biff controlled his dog
and
Biff controlled his temper.
Like many conceptual metaphors, S
ELF-CONTROL IS PHYSICAL EFFORT
turns out to have a kernel of neurobiological reality.
In a remarkable set of experiments, Baumeister and his collaborators have shown that self-control, like a muscle, can become fatigued. Their laboratory procedure is best introduced by quoting from the Method section of one of their papers:
Procedure.
Participants signed up for a study on taste perception. Each participant was contacted to schedule an individual session, and at that time the experimenter requested the participant to skip one meal before the experiment and make sure not to have eaten anything for at least 3 hr.
The laboratory room was carefully set up before participants in the food conditions arrived. Chocolate chip cookies were baked in the room in a small oven, and, as a result, the laboratory was filled with the delicious aroma of fresh chocolate and baking. Two foods were displayed on the table at which the participant was seated. One display consisted of a stack of chocolate chip cookies augmented by some chocolate candies. The other consisted of a bowl of red and white radishes.
112
 
The cover story was that the experiment was on sensory memory and that the participants would experience one of two distinctive tastes and have to recall its qualities after a delay. The experimenter told half the participants to eat two or three of the cookies, and the other half to eat two or three of the radishes. She left the room and watched through a one-way mirror to confirm that the participant did not cheat. The article notes: “Several of them did indicate clear interest in the chocolates, to the point of looking longingly at the chocolate display and in a few cases even picking up the cookies to sniff at them.” The experimenter then told them they would have to wait fifteen minutes for the test of their memory of the taste. In the interim, they were to solve some puzzles that required tracing a geometric figure with a pencil without either retracing a line or lifting the pencil off the paper. Compounding the sadism, the experimenters had given them puzzles that were unsolvable, and measured how long the participant persisted before giving up. The ones who had eaten the cookies spent 18.9 minutes and made 34.3 attempts to solve the puzzle. The ones who had eaten the radishes spent 8.4 minutes and made 19.4 attempts. Presumably the radish eaters had depleted so much of their mental strength in resisting the cookies that they had little left to persist in solving the puzzles. Baumeister called the effect
ego depletion
, using Freud’s sense of
ego
as the mental entity that controls the passions.
The study raises many objections: maybe the radish eaters were just frustrated, or angry, or in a bad mood, or hungry. But the Baumeister team addressed them and over the following decade accumulated a raft of experiments showing that just about any task that requires an exercise of willpower can impede performance in any other task that requires willpower. Here are a few tasks that can deplete the ego:
• Name the color in which a word is displayed (such as the word RED printed in blue ink), ignoring the color it spells out (the Stroop task).
• Track moving boxes on a screen, as if playing a shell game, while ignoring a comedy video on an adjacent screen.
• Write a convincing speech on why tuition fees should be raised.
• Write an essay about the typical day in the life of a fat person without using any stereotypes.
• Watch the scene in
Terms of Endearment
in which a dying Debra Winger says good-bye to her children, without showing emotion.
• For racially prejudiced people, carry on a conversation with an African American.
• Write down all your thoughts, but don’t think of a polar bear.
113
 
And here are some of the lapses in willpower that result:
• Giving up sooner when squeezing a handgrip, solving anagrams, or watching a movie of a box on a table until something happens.
• Breaking a diet by eating ice cream from a container after rating a spoonful in a taste experiment.
• Drinking more beer in a taste experiment, even when having to take a simulated driving test immediately afterward.
• Failing to stifle sexual thoughts, such as in solving the anagram NISEP as
penis
rather than as
spine
.
• Failing to keep up a running conversation while teaching someone how to putt in golf.
• Being willing to pay more for an attractive watch, car, or boat.
• Blowing your payment for participation in the study on gum, candy, Doritos, or playing cards, which the experimenters had mischievously offered for sale.
 
Various control conditions allowed the psychologists to rule out alternative explanations such as fatigue, difficulty, mood, and lack of confidence. The only common denominator was the need for self-control.
An important implication of the research is that the exercise of self-control can conceal the differences among individual people.
114
It’s no coincidence that 1960s popular culture, which denigrated sobriety and self-control, also denigrated conformity, as in the signature motto “Do your own thing.” Everyone has a different thing, but society insists on just one thing, so we must apply self-control to do it. If self-control flattens individuality, one can predict that when the ego is depleted, individuality will pop back up. And that is what the Baumeister group found. In the ice-cream-tasting experiment, when the participants had not been called on to exercise self-control beforehand, the dieters and the indiscriminate eaters consumed the same amount of ice cream. But when their willpower had been exhausted, the dieters ate more. Other individual differences unmasked by depletion of the ego included the degree of stereotyping by prejudiced and unprejudiced people, the amount of beer drunk by tipplers and moderate drinkers, and the amount of small talk made by shy and outgoing people.
The Baumeister group also vindicated the Victorian idea that some people—particularly men—have to exert their will to control their sexual appetites.
115
In one study, the psychologists assessed how emotionally close a participant had to feel to another person before engaging in casual sex. People of both sexes differ along that dimension, and there is also a robust difference between the sexes, captured in the movie dialogue in which Diane Keaton says, “I believe that sex without love is a meaningless experience” and Woody Allen replies, “Yes, but as meaningless experiences go, it’s one of the best.” Half the participants in the study went through an ego depletion task (crossing out letters according to shifting rules), and all were then asked to imagine themselves being in a committed romantic relationship and then finding themselves in the hotel room of an attractive acquaintance of the opposite sex. They were then asked whether they imagined themselves succumbing to the temptation. Whether their wills had been tuckered or not, the participants (of both sexes) who had indicated that sex without love was a meaningless experience imagined they would resist the temptation. But a transient weakness of their will affected the ones who were more open to casual sex: if their ego had just been fatigued, their imagined selves were far more likely to say yes.

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