Over-the-top teens like lazy A.J. Soprano and "Desperate Housewives" angst-ridden Andrew and impulsive Danielle reflect our culture's convictions that teens are angry, oversexed risk-takers.
So 17-year-old Ali Nepola, who's at the top of her class, cross-country team captain, a competitive dancer, and popular and well behaved to boot, doesn't quite fit the stereotype. According to new research, Ali's self-control may be the key to her success.
"She's got a lot of self-control and knows her limitations and knows her strengths and weaknesses," says Cathy Nepola, Ali's mom.
Grazyna Kochanska, a professor at the University of Iowa, has tracked Ali and more than 300 other kids for almost 20 years to gauge how their ability to delay gratification and exert self-control affects their lives.
"Self-control is generally considered a very good thing," Kochanska says. "In our own research, this capacity has clearly been associated with positive aspects of social development."
Using a variety of measures, Kochanska and her team test children on how well they can control their impulses. Some tests involve letting a child see a particular reward -- a wrapped present, a piece of candy, an attractive toy -- but not allowing him to touch the item until given permission. Others involve building a tall structure with blocks, then asking the child to wait a specified time before allowing him to knock it down.
Videotaped at 3 years old, Ali is told she can eat the candy placed in front of her but only after the researcher rings a bell. On the video, Ali hops around a bit but does not touch the candy.
In another test, Ali waits more than three minutes -- an eternity to a 3-year-old -- to unwrap a present left just within her reach. Kochanska says this ability to delay gratification will benefit Ali throughout her life.
"Those who have good self-control are more compliant, more cooperative, have good harmonious relationships with their parents, good relationships with their peers, and they have good academic success," Kochanska says.
But watch almost any teen movie, and you may wonder why impulse control seems to skid off the road during the scary teen years. Experts now know this is because the brain is not fully developed at adolescence.
"If we were to compare the teenage brain to an automobile, it's as if the gas pedal is to the floor, and there are no brakes," says David Walsh, author of "Why Do They Act That Way: A Survival Guide to the Adolescent Brain for You and Your Teen."
Thanks to magnetic resonance imaging, or MRI, technology, we know that the teen brain develops from back to front. In other words, the part of the brain that helps teens reason, plan ahead and manage impulses -- the prefrontal cortex -- is one of the last areas to mature, at around age 25. Until then parents may have a hard time engaging their teens.
"If parents create a supportive, loving, well-organized, predictable environment in the home, I think those children will be all right," Kochanska says.
And that's just the sort of environment Ali's parents provided for her.
"Pretty much been the way that she's been raised is that you don't always get what you want when you want it," says Cathy Nepola. "You just have to wait sometimes, and sometimes when you wait, it's even better."
Learning to delay gratification and exercise self-control are lessons Ali will take with her into her adult years.