(AP) Tasha Henderson got tired of her 14-year-old daughter's poor grades, her chronic lateness to class and her talking back to her teachers, so she decided to teach the girl a lesson.

She made Coretha stand at a busy Oklahoma City intersection Nov. 4 with a cardboard sign that read: "I don't do my homework and I act up in school, so my parents are preparing me for my future. Will work for food."

"This may not work. I'm not a professional," said Henderson, a 34-year-old mother of three. "But I felt I owed it to my child to at least try."

In fact, Henderson has seen a turnaround in her daughter's behavior in the past week and a half. But the punishment prompted letters and calls to talk radio from people either praising the woman or blasting her for publicly humiliating her daughter.

"The parents of that girl need more education than she does if they can't see that the worst scenario in this case is to kill their daughter psychologically," Suzanne Ball said in a letter to The Oklahoman.

Marvin Lyle, 52, said in an interview: "I don't see anything wrong with it. I see the other extreme where parents don't care what the kids do, and at least she wants to help her kid."

Coretha has been getting C's and D's as a freshman at Edmond Memorial High in this well-to-do Oklahoma City suburb. Edmond Memorial is considered one of the top high schools in the state in academics.

While Henderson stood next to her daughter at the intersection, a passing motorist called police with a report of psychological abuse, and an Oklahoma City police officer took a report. Mother and daughter were asked to leave after about an hour, and no citation was issued. But the report was forwarded to the state Department of Human Services.

"There wasn't any criminal act involved that the officer could see that would require any criminal investigation," Master Sgt. Charles Phillips said. "DHS may follow up."

DHS spokesman Doug Doe would not comment on whether an investigation was opened, but suggested such a case would probably not be a high priority.

Tasha Henderson said her daughter's attendance has been perfect and her behavior has been better since the incident.

Coretha, a soft-spoken girl, acknowledged the punishment was humiliating but said it got her attention. "I won't talk back," she said quietly, hanging her head.

She already has been forced by her parents to give up basketball and track because of slipping grades, and said she hopes to improve in school so she can play next year.

Donald Wertlieb, a professor of child development at the Eliot-Pearson Department of Child Development at Tufts University, warned that such punishment could do extreme emotional damage. He said rewarding positive behavior is more effective.

"The trick is to catch them being good," he said. "It sounds like this mother has not had a chance to catch her child being good or is so upset over seeing her be bad, that's where the focus is."