When they were tested a decade later, the ones who had shown greater willpower in the marshmallow test had now turned into adolescents who were better adjusted, attained higher SAT scores, and stayed in school longer. When they were tested one and two decades after that, the patient children had grown into adults who were less likely to use cocaine, had higher self-esteem, had better relationships, were better at handling stress, had fewer symptoms of borderline personality disorder, obtained higher degrees, and earned more money.
Other studies with large samples of adolescents and adults have documented similar payoffs. Adults can wait indefinitely for two marshmallows, but as we have seen, they can be given equivalent choices such as “Would you rather have five dollars now or forty dollars in two weeks?” Studies by Laibson, Christopher Chabris, Kris Kirby, Angela Duckworth, Martin Seligman, and others have found that people who opt for the later and larger sums get higher grades, weigh less, smoke less, exercise more, and are more likely to pay off their credit card balance every month.94
Baumeister and his collaborators measured self-control in a different way.95 They asked university students to divulge their own powers of self-control by rating sentences such as these:I am good at resisting temptation.
I blurt out whatever is on my mind.
I never allow myself to lose control.
I get carried away by my feelings.
I lose my temper too easily.
I don’t keep secrets very well.
I’d be better off if I stopped to think before acting.
Pleasure and fun sometimes keep me from getting work done.
I am always on time.
After adjusting for any tendency just to tick off socially desirable traits, the researchers combined the responses into a single measure of habitual self-control. They found that the students with higher scores got better grades, had fewer eating disorders, drank less, had fewer psychosomatic aches and pains, were less depressed, anxious, phobic, and paranoid, had higher self-esteem, were more conscientious, had better relationships with their families, had more stable friendships, were less likely to have sex they regretted, were less likely to imagine themselves cheating in a monogamous relationship, felt less of a need to “vent” or “let off steam,” and felt more guilt but less shame.96 Self-controllers are better at perspective-taking and are less distressed when responding to others’ troubles, though they are neither more nor less sympathetic in their concern for them. And contrary to the conventional wisdom that says that people with too much self-control are uptight, repressed, neurotic, bottled up, wound up, obsessive-compulsive, or fixated at the anal stage of psychosexual development, the team found that the more self-control people have, the better their lives are. The people at the top of the scale were the mentally healthiest.
Are people with low self-control more likely to perpetrate acts of violence? Circumstantial evidence suggests they are. Recall from chapter 3 the theory of crime (championed by Michael Gottfredson, Travis Hirschi, James Q. Wilson, and Richard Herrnstein) in which the people who commit crimes are those with the least self-control.97 They opt for small, quick, ill-gotten gains over the longer-term fruits of honest toil, among them the reward of not ending up in jail. Violent adolescents and young adults tend to have a history of misconduct at school, and they tend to get into other kinds of trouble that bespeak a lack of self-control, such as drunk driving, drug and alcohol abuse, accidents, poor school performance, risky sex, unemployment, and nonviolent crimes such as burglary, vandalism, and auto theft. Many violent crimes are strikingly impulsive. A man will walk into a convenience store for some cigarettes and on the spur of the moment pull out a gun and rob the cash register. Or he will react to a curse or insult by pulling out a knife and stabbing the insulter.
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