Patricia Gage was doing her best in 1995 teaching Advanced Placement (AP) English literature at W.T. White High School in Dallas. She had 70 seniors in three sections, and they tried hard. But many of them could not afford the test fee -- about $72. Of the 11 students who took the three-hour examination, only six received a score high enough to qualify for college credit.

Then something happened that startled and pleased Gage. If it spreads, it may radically change the way U.S. high schools motivate students.

Schools like White High with low participation and low passing rates on the difficult AP exams usually just try to persevere, arranging more training for their teachers and more study time for students when they can, and looking for money to pay the testing fees. But in 1996 White High and several other Dallas schools, followed by many others schools in Texas, got lucky. The educationally-oriented O'Donnell Foundation in Dallas, joined by the state of Texas, the Dallas school district and several other private benefactors, began what has become so far an investment of $25 million in AP. They have provided more money for training, for tutoring, for paying test fees and even for coordinating pre-AP instruction in middle school.

And the program sponsors have done one more thing: they have paid money bonuses to students, and to their teachers, for AP tests that received high scores.

This is not the pizza-party pocket change that teachers are used to. Gage, 55, has a master's degree and 34 years of experience, which entitles her to a base pay of $66,000 a year. In 2003, she earned an extra $7,350 when 49 of her 110 students received a grade of 3 or higher on the 5-point AP English literature test. She got another $500 on top of that because those students did better than her 2002 classes.

Gage also received $1,200 for participating in training sessions and coordinating with her local middle schools, and another $2,500 for 20 hours a month of extra tutoring over 10 months. That money was also welcome, but it is not unusual for teachers to get more money for putting in more hours. The bonuses for good scores were something else again.

Many students also scored big, academically and financially. Will Robison, who graduated this year from Rider High School in Wichita Falls, Tex., earned a total of $700 in his junior and seniors years for scores of 3 and above on AP tests in biology, English language, English literature, economics, calculus and two courses in physics.

This is not the way public education works in the United States. Parents and grandparents may award money prizes for good grades, but school administrators almost never do. Many educators agree with writer and lecturer Alfie Kohn that such payments are ill-considered bribes that eventually kill the love of learning that should be at the heart of good teaching. And even if they wanted to pay bonuses, there would be no money for them in their budgets.

But the impressive results of the Texas experiment suggest that other districts, if they can get similar support from their states and their local foundations and businesses, may soon be doing the same. Some states, such as Florida, already mandate extra payments to schools and teachers for good AP results. The Maddox Foundation in southern New Mexico is paying AP bonuses to its students and teachers. School superintendent Terry B. Grier in Guilford County, N.C., does not have enough money for bonuses for every good score, but he has found that students are greatly motivated by his annual summer "Cool to Be Smart" celebration in which students who have taken AP or International Baccalaureate tests have a chance to win door prizes that include laptops, $1,500 scholarships and even a new car.

Gage at White High School in Dallas said she was deeply skeptical about the money promises when O'Donnell and the Dallas school system announced its incentive program for 10 schools in 1996. "I couldn't believe that someone was going to pay me extra dollars for something that I already did," she said.

But the money came in handy, and she was thrilled at what it did for her students. The six passing scores she had in 1995 jumped to 17 passing scores with the same number of students in 1996, the first year of the program. It did not stop there. In 2000 she had 56 passing scores, and has stayed close to that level since.

White High drew students from mostly middle-class neighborhoods when she began teaching there, but by the 1990s an influx of immigrants and other low-income families had changed the school's demographic profile. The AP incentive money came at just the right time. She found students much more willing to put in the extra hours they needed to do well on the AP tests, designed to be the equivalent of final exams in introductory college courses.

"I call myself the Statue of Liberty," Gage said. "Give me your poor, your huddled masses, anyone who wants to take AP."

Gregg Fleisher, president of Dallas-based AP Strategies, the nonprofit set up by the O'Donnell Foundation to run the program, said I am wrong to think that high-scoring AP students in other parts of the country don't get rewarded for their hard work. They win scholarships, they get college credit and they are accepted to selective schools that prepare them for satisfying and financially rewarding careers, he said. They grow up in families where those long-term incentives are made clear, and Fleisher sees nothing wrong with a little cash to motivate students who have not been raised from birth to see the benefits of sticking it out in AP chemistry.

In Texas, different benefactors have adopted different school districts, and the bonus rules vary. Some pay $100 per passing score on an AP test. Some pay $150. Some don't pay for the most popular history tests, preferring to focus their resources -- which are not unlimited -- on science, English and math.

But the impact on AP participation has been remarkable. The number of AP exams per 1,000 juniors and seniors in the 10 Dallas high schools that are part of the original incentive program jumped from 55 in 1995 to 279 in 2003, compared to an increase of 77 to 139 per thousand for all U.S. public schools and 64 to 168 per thousand for all Texas public schools in that same period.

Fleisher said he is particularly pleased at what the program has done for AP participation by African-American and Hispanic students, who are much more likely to graduate from college if they take AP or IB courses and tests in high school. In 1995 in those 10 Dallas schools, non-Hispanic white students had scores of 3 or above in 23 out of every 1,000 AP tests, compared to only 10 passing scores out of every 1,000 tests for African-American and Hispanic students. Both groups have improved markedly, but the minority students have surged ahead of the whites, with 101 passing scores per 1,000 AP tests in 2003 compared to 89 passing scores per 1,000 tests for Anglo students.

Has all the emphasis on payoffs killed the love of intellectual discovery for the participating students? It is hard to tell. No one has surveyed the high schoolers on this question. Will Robison took 12 AP tests in high school and got passing scores in all, although he was not paid for the social studies tests. He said he liked the program because of the bonuses and because of the many credits that will help him when he enrolls this year at the University of Texas -- Austin.

When I asked him if all these extrinsic rewards had wiped out more natural motivations, such as curiosity, he gave me the following answer, which you hear often in high schools these days: "I think the pure joy of learning has been gone from our school systems for a while and I don't think paying for AP is the reason for that."

Whatever is happening, it seems to be helping many students who would never have even thought of AP in the past. Gage's favorite story is about Deshun Ransom, one of her AP English students. He was often in trouble, and not doing well academically, until he asked about a mythology book she had out on a table during a yearbook picture taking session. She said her AP English students were reading it and she persuaded him to enroll.

Whether it was the promise of money or the skill of Gage's teaching, Ransom began to do his homework, something he had not bothered with before. He took the AP literature test and did so well that he persuaded the school to let him take, at the very last minute, the AP language test a few days later. He received scores of 3 on both, and is now attending Paul Quinn College.

Ransom calls Gage occasionally to get her advice on papers he had written. "He calls me his Obi-Wan Kenobi, and he is my Luke Skywalker," Gage said. "That is good enough for me."