Everyone knows that Long Island, New York, a suburban area outside New York City, is filled with picturesque, tree-lined towns and neighborhoods, the kind that parents dream about for raising their kids. It’s the last place you’d ever find the kind of problems that inhabit the mean streets of the big city.

So if Long Island neighborhoods represent the idyllic setting for raising children, why were three students at North Babylon High School, ages 14, 14 and 15, arrested for beating up a 13-year-old girl in front of the local elementary school on Dec. 18? What makes kids who should be growing up middle class, confident and full of self-esteem want to become bullies?

The answer to that question speaks to the very nature of today’s schoolyard bully.

Back in the day, bullies were thought to be social pariahs plagued by low self-esteem who needed to pick on others to make themselves feel good. However, researchers around the world are discovering that just isn’t the case.

Dan Olweus, Ph.D, of the Research Centre for Health Promotion, University of Bergen, Norway, is considered the "founding father" of research on bullying. In his 1993 book, "Bullying At School: What We Know and What We Can Do," Dr. Olweus identifies the common characteristics of a bully.

His research shows bullies:

--Have a strong need to dominate and subdue other students and to get their own way

-- Are impulsive and are easily angered

--Are often defiant and aggressive toward adults, including parents and teachers

--Show little empathy toward students who are victimized

--Are physically stronger (this applies to boys)

Dr. Dorothy L. Espelage, associate professor of educational psychology at the University of Illinois at Urbana-Champaign, is another noted authority on bullying. In a March 2006 article titled, "Bullied...to Death? How to Spot and Prevent Childhood Violence on the Internet," published in the Ladies Home Journal, Dr. Espelage was quoted as making the following observation: “We used to think that bullies were social outcasts with such low self-esteem that they needed to pick on others to feel good about themselves. But in fact bullies are just as likely to be the popular kids, admired by peers and teachers, especially if they're attractive and athletic."

And forget about the disadvantaged background when you’re trying to work up a definition of a bully.

In that same article, Dr. Espelage went on to add, "You’ll find bullies in intact families of high economic status."

Was there some emotional trigger that caused those North Babylon High School students to act as they did?

Probably not, says Nancy Mullin, M.Ed., director of the Project on Teasing and Bullying, Wellesley Centers for Women, Wellesley College, in Wellesley, Mass. Bullying begins in some kids as early as pre-school and escalates over time until it becomes a regularized form of behavior, she said.

In the case of the North Babylon students, Nancy Mullin feels that their bullying behavior went on in some other form long before the actual incident that got them arrested. She also noted that the incident was an assault, which is the next level up from bullying. As Ms. Mullins pointed out, you can look at the behavior as a continuum stretching across a page, with one end being joking and the other end being violence.

Joking is acceptable because we do it with friends and there is a mutuality to it. Joking turns to teasing when it takes on a mean-spirited edge. Bullying can take on a variety of forms, the most common being verbal.

However, there can be a physical aspect to it as well. Bullies usually don’t rely on one form of aggression. They typically combine strategies to get the optimum advantage in a “power over” situation.

It’s the power-over aspect to bullying that distinguishes it from the other activities kids get into like rough and tumble play, says Ms. Mullins. It can easily escalate into other forms of violence, and if the behavior is carried over into adult life, it can take the form of assault, racial discrimination or sexual abuse.

Parents can spot a child who is becoming a bully because they manifest certain specific behaviors:

--They tend not to feel empathy

--They feel their actions are justified

--They use aggressive behavior with siblings and peers

Nancy Mullins describes these kids as, “having to be the boss of everything.”

If your child exhibits these kinds of attitudes, you need to set guidelines as to what is acceptable behavior. Teach them to be kind and empathic, as well as what the repercussions are to their inappropriate behavior.

Ms. Mullins emphasizes it isn’t just a question of telling your kids that someone’s feelings get hurt, because for a bully, that’s exactly the outcome they are hoping to achieve. Instead, set negative consequences. Since bullying takes place in a social situation, take away the child’s social privileges until the behavior stops.

And mom and dad, you need to practice what you preach. If you fly off the handle every time something goes wrong, then you’re modeling the very behavior you’re trying to stop in your child.

If you’re going to change a bullying behavior, your motto has to be, “Do as I do, not do as I say.”

Foxnews.com Health contributor Maria Esposito contributed to this report.

Click here to check out Dr. Manny's book The Check List (Harper Collins, 2007)

Dr. Manny Alvarez is the managing editor of health news at FOXNews.com, and is a regular medical contributor on the FOX News Channel. He is chairman of the Department of Obstetrics and Gynecology and Reproductive Science at Hackensack University Medical Center in New Jersey. Additionally, Alvarez is Adjunct Professor of Obstetrics and Gynecology at New York University School of Medicine in New York City.

Dr. Manny Alvarez serves as Fox News Channel's senior managing health editor. He also serves as chairman of the department of obstetrics/gynecology and reproductive science at Hackensack University Medical Center in New Jersey. Click here for more information on Dr. Manny's work with Hackensack University Medical Center. Visit AskDrManny.com for more.