WASHINGTON, AUG 8: After learning a new physical skill, such as riding a bike, it takes six hours to permanently store the memory in the brain. But learning another new skill too quickly may erase that first lesson, according to research into memory and the mind.

The study concludes that routine activity or rest between intense learning sessions may be essential to retention of a skill.

``We've shown that time itself is a very powerful component of learning,'' said Henry H Holcomb, psychiatrist in charge of a study at Johns Hopkins University on how people remember. ``It is not enough to simply practice something. You have to allow time to pass for the brain to encode the new skill,'' Holcomb said.

The researchers used a device that measures blood flow in the brain. They concluded it takes five to six hours for the memory of a new skill to move from a temporary storage site in the front of the brain to a permanent storage site at the back.

During those six hours, said Holcomb, there is a ``neural window of vulnerability'' when that new skill can be easily eroded from memory if the person attempts to learn a second new skill.

``If you were performing a piano piece for the first time and then immediately started practicing something else, then that will cause problems in retention of the initial piece that you practiced,'' said Holcomb.

It would be better, he said, if the first practice session were followed by five to six hours of routine activity that required no new learning.

A report on the study is to be published today in the journal Science. This is a new and important insight into the relationship between ``motor skill learning and neural activity,'' said Carolyn B Cave, a psychologist and learning researcher at Vanderbilt university.

She cautioned, however, that not enough is known to identify precisely how the successive learning of different skills could interfere with each other.

``The brain is incredibly flexible,'' said Cave. ``It may not be, for instance, that practicing the piano would interfere with what you learned just before from a tennis lesson. The two skills could use different parts of the brain.''

Copyright © 1997 Indian Express Newspapers (Bombay) Ltd.