Classical music may only have limited effects on academic performance according to a study released Wednesday by Harvard's Graduate School of Education.

The study counters popularly-held theories that say exposure to and participation in music and drama lead to increases in test scores and grades.

The three-year study completed by Harvard Project Zero researchers Ellen Winner '69 and Lois A. Hetland, was a synthesis of various individual studies on arts education conducted over the past 50 years.

According to the researchers, their study is the largest and most comprehensive study ever conducted on the link between arts education and performance in academic disciplines.

"Nobody has ever looked carefully at the evidence," Winner said.

The study does not completely dismiss the so-called "Mozart effect"--that music can be beneficial to overall well-being--but is more reserved in describing the benefits produced by art.

The study indicated there is clear evidence that children who learn to make music have permanently-improved spatial skills--the ability to imagine objects and manipulate them mentally.

The researchers also found students' verbal skills were improved when they participated in dramatic arts in school.

Yet these improved skills did nothing to increase students' test scores or grades.

The researchers said previous studies that show a connection between music and better test grades fail to take into account the students' academic ability.

Don G. Campbell, the author of The Mozart Effect for Children, said he doubted a study could accurately uncover all the benefits of a child's participation in music or the arts.

"The Mozart effect is far more than one study can measure," Campbell said. "The rhythm, harmony and melodies of music all create different perceptions and sensations within different regions of the brain."

However, Campbell said he was pleased that scientific studies are starting to focus on the effect--which he has helped to make widely known--and able to demonstrate proven benefits.

The Harvard researchers have cautioned that their study should not be interpreted as evidence justifying the removal of arts education programs from schools. Winner said she has already heard from educators who worry that the study will have such an effect.

"We don't want arts to be pushed out [of schools]," Winner said.

Rather, the researchers indicate that they want schools to better understand what they will get out of their arts education program.

Winner said national figures such as First Lady Hillary Clinton and Education Secretary Richard Riley have publicly urged schools to include arts as a way to improve academic performance. Making these sorts of claims, Winner said, may backfire on arts education supporters when test scores do not increase and the programs are consequently eliminated.