Wichita ? Children in a Wichita school playground were targets of verbal or physical harassment about once every five minutes, according to a study published in the journal Child Development.

Jim Snyder, a psychology professor at Wichita State University, studied 266 kindergartners under a $2.5 million grant from the National Institute of Mental Health.

His research, conducted over two years, raises new concerns about bullying.

The study found that the teasing, name-calling, poking, pushing and shoving happened more frequently than some parents might think.

“What was most surprising was just how much of it there was,” Snyder said.

The study found harassment decreased as students moved on from kindergarten and learned to deal with it better.

But about 10 percent of those followed in the study become chronic victims, he said.

“Very early on, the way you establish yourself among your peers turns out to be very important — and not just at school,” Snyder said.

Harassed children show more anti-social or aggressive behavior at home, yet were more sad and withdrawn. Those children also were more likely to have poor grades.

Researchers followed a group of students at a Wichita elementary school beginning in the fall of 1998. The study did not indicate the name of the school because of privacy concerns.

Trained observers watched the students several times at recess during their kindergarten and first-grade years, logging behaviors but not intervening.

Earlier research on aggressive behavior had relied on reporting by students, teachers or parents, Snyder said.

“That doesn’t give you the feel for the day-to-day, minute-to-minute level of victimization that goes on,” he said. “We were essentially out there, in the laboratory.”

Researchers tracked academic performance and asked teachers and parents to fill out questionnaires about their students’ behavior.

They found that boys and girls behaved differently.

Boys tend to run in large groups, Snyder said. They value competition and are more likely to tease “weaker” children.

Girls tend to relate one-on-one or in small groups and value cooperation. Their aggression is more covert, he said.

“It’s, ‘Did you see what so-and-so is wearing?’ or ‘We’re not going to play with you anymore,”‘ Snyder said.

The study serves as a reminder that anti-bully programs are vital at all grade levels, said Debbie McKenna, the Wichita district’s supervisor for safe and drug-free schools.

One Wichita program, “Bullyproofing Your School,” teaches elementary school students ways to deal with a bully. Older children participate in “Second Step,” a program that highlights empathy, impulse control and anger management.

A growing challenge for teachers and playground monitors, McKenna said, is teaching children that television behavior is not always appropriate.

“We now have an entire school system of kids who have been raised on sitcoms,” McKenna said.

“Somebody puts somebody down, and the laugh track comes on. Then they slam back with another insult, and it continues.”