A study in which students carried electronic beepers and recorded their feelings when buzzed provided an unusual glimpse into the adolescent psyche and indicates some stereotypes are false, researchers say.

University of Illinois and Loyola University researchers gave beepers to 480 students in grades five to nine in suburbs southwest of Chicago and asked them to write down their thoughts when buzzed every two hours or so.The results: 20,000 musings on adolescent concerns ranging from television to love, including the finding that most youths felt best doing sports and worst doing homework.

"We hope that this study will not merely be 20,000 individual snapshots, but rather a motion picture of what life as an adolescent is actually like," the researchers write in an article accepted for publication in the journal Child Development this September.

Contrary to the popular image of music-crazed adolescents glued to their stereos, girls who took part in the study reported listening to music only 1.8 hours a week, compared with 1.2 hours a week among boys.

Overall, girls spent more time studying, talking and grooming and less time watching television than boys, the study found.

But regardless of sex or age, the participants didn't appear to enjoy television much, reporting average or below-average moods while watching it, the researchers said.

Ninth-graders said they were in bad moods about 11 percent of the time, compared to 6 percent for fifth-graders. By contrast, the younger students reported feeling great 25 percent of the time, compared to 12 percent among the ninth-graders.

The older teenagers "face more difficulties as they move into junior high school and the dating life," said University of Illinois researcher Reed Larson. "They become less naive and more aware that life isn't all roses."

His colleague, Loyola psychologist Maryse Richards, said the study provides a more accurate portrait than traditional research in which subjects are interviewed or asked to fill out questionnaires about past events or feelings.

Memories can play tricks when people try to recall exact details of their lives, Richards said.

Students carried beepers between 1985 and 1987, and the researchers plan a follow-up on the same students next year.

The researchers said some of their findings were more surprising than others.

As expected, older youths reported feeling in love more often than younger students. But sports got high marks as a favored activity for all age groups.

"Kids feel better doing sports than just about any other activity," Richards said. "They feel most energized, happy and cheerful."

Girls did about seven hours a week of homework while boys did about six, she said. "Of all their activities, they feel worst while doing homework," Richards said.

About 30 percent of eighth- and ninth-grade girls were excessively worried about their weight, compared to less than 10 percent of the boys.

Overall, boys spent more time doing yard work, and girls did more cooking and cleaning.

"There's a lot more sex typing than I thought," Richards said. "We're still treating kids with the expectation they will become traditional men and women."