Musicians often play the same piece of music over and over, long past the point of mastery. Researchers debate whether there is any benefit to “overlearning” a skill in that way.
Now, researchers at Brown University suggest there is a previously unknown benefit to continuing to train after one’s performance has plateaued: Even just 20 minutes of overlearning locks in a new skill, shielding it from being overwritten by other information.
“If you’d like to learn something very important, then you can protect that from being disrupted by new learning,” says study coauthor Takeo Watanabe, who studies vision and learning at Brown. But be warned, he notes: Because overlearning blocks subsequent learning, it may prevent you from learning a series of similar things in rapid succession.
The work was published online last month in the journal Nature Neuroscience.
Overlearning has been a controversial topic in psychology — some evidence suggests it provides no long-term benefit — yet it continues to be common practice for musicians, athletes, martial artists, and more. Watanabe hypothesized that there must be some benefit for overlearning — why else do so many people keep practicing long after they’ve become masters?
He and colleagues invited a group of volunteers to learn a new visual skill, involving distinguishing between patterned images and random ones. In one experiment, participants learned the skill, waited a set length of time, then learned a new, but related, skill. Another group did the same thing, but learned the first skill twice before moving on to the second skill.
When regular learners were taught the second task shortly after the first one, they didn’t learn the first skill as well, as if the second skill session interfered. But overlearning prevented that interference, the team found: Volunteers who overlearned the first task were able to later recall it well, as if it had been cemented in their minds. But those overlearners did not learn the second skill as successfully as the regular learners.
To see if they could figure out why this was occurring, the researchers used a technique called magnetic resonance spectroscopy (MRS) to monitor areas of the brain involved in vision. MRS is similar to MRI, but MRS detects concentrations of chemicals in the brain rather than brain structures.
During the first bout of learning in all the participants, the researchers detected higher levels of an excitatory brain chemical, called glutamate, than its inhibitory counterpart, GABA. Glutamate promotes brain cells to morph and change, or be “plastic,” which is required to learn and store memories in the brain.
When regular learners moved onto a second skill, their brain regions were still hot with glutamate, ripe for new learning and overwriting previous learning. But when overlearners stuck with the first skill for an extra 20 minutes, their levels of GABA, the inhibitory chemical, climbed and silenced the brain cells. In other words, the brains of the overlearners hunkered down, protecting the original learning from change.
So maybe practice does make perfect — if you spend a little extra time to lock it in.
“Overlearning is very effective, though at the expense of learning something similar,” says Watanabe. He hopes that this type of learning will help skills stick in the brain longer, but additional, long-term studies will need to test that hypothesis.
Megan Scudellari can be reached at firstname.lastname@example.org