University of Toronto researchers discover how practice makes perfect in brain

November 09, 1999

From recognizing a wrong note on a violin to identifying the vintage of a wine, people learn to make subtle perceptual judgements with practice because the brain becomes more efficient in extracting the relevant information for the task, says a study in the Nov. 11 issue of Nature.

"Whenever you learn something new, your brain changes in a variety of ways. Until now we didn't know exactly how those changes were linked to behaviour," says study co-author Professor Allison Sekuler of U of T's department of psychology. Researchers have long known that people's ability to make perceptual judgements improves with practice, but until now they have never known why.

One theory suggests that learning decreases the variability in the way people's perceptual systems encode sights, smells, and sounds -- perception becomes more consistent and reliable. Another theory proposes that individuals become more efficient at encoding relevant information, and therefore become more sensitive to small differences among objects.

"As an analogy, imagine watching two televisions with poor reception," says co-author Professor Patrick Bennett, also of the department of psychology. "In one case, the programs from two or three stations are mixed up on one channel, so the image is visible but very unstable. In the other case, only one station is shown, but its signal is so faint that you can barely see it. The way to improve the first television is to increase its stability -- which means decreasing its variability. The way to improve the second television is to increase its sensitivity to the station's signal. The question is: Which kind of improvement produces perceptual learning?"

To answer this question, researchers trained people to identify photos of 10 unfamiliar human faces embedded in varying degrees of visual camouflage resembling the black and white static on an untuned TV. After several days, performance improved by up to 400 per cent and people were able to identify faces that were nearly invisible to them at the start of training. To see if this improvement was caused by a reduction in the brain's variability, the researchers presented the same sequence of patterns again and measured response consistency.

"If learning reduces the brain's variability, the response consistency would have increased with practice, but it didn't," Bennett says. The failure to see any change in response consistency demonstrates that learning occurred because the people were becoming more efficient at encoding the visual information relevant to face identification.

The same results were found in a second study that used abstract visual patterns rather than faces. "The fact that we get the same effect with two very different kinds of stimuli suggests that we've tapped into a really basic property of learning," says Jason Gold, co-author and graduate student in the psychology department.

"Now that we have this knowledge, the next step is to determine at what precise levels in the brain these processes occur," says Sekuler. "This fundamental knowledge may help us develop techniques to investigate and improve many other types of learning in people -- from learning to read to playing the violin."

The study was funded by grants from the Natural Sciences and Engineering Research Council of Canada.
-end-


University of Toronto

Related Brain Articles from Brightsurf:

Glioblastoma nanomedicine crosses into brain in mice, eradicates recurring brain cancer
A new synthetic protein nanoparticle capable of slipping past the nearly impermeable blood-brain barrier in mice could deliver cancer-killing drugs directly to malignant brain tumors, new research from the University of Michigan shows.

Children with asymptomatic brain bleeds as newborns show normal brain development at age 2
A study by UNC researchers finds that neurodevelopmental scores and gray matter volumes at age two years did not differ between children who had MRI-confirmed asymptomatic subdural hemorrhages when they were neonates, compared to children with no history of subdural hemorrhage.

New model of human brain 'conversations' could inform research on brain disease, cognition
A team of Indiana University neuroscientists has built a new model of human brain networks that sheds light on how the brain functions.

Human brain size gene triggers bigger brain in monkeys
Dresden and Japanese researchers show that a human-specific gene causes a larger neocortex in the common marmoset, a non-human primate.

Unique insight into development of the human brain: Model of the early embryonic brain
Stem cell researchers from the University of Copenhagen have designed a model of an early embryonic brain.

An optical brain-to-brain interface supports information exchange for locomotion control
Chinese researchers established an optical BtBI that supports rapid information transmission for precise locomotion control, thus providing a proof-of-principle demonstration of fast BtBI for real-time behavioral control.

Transplanting human nerve cells into a mouse brain reveals how they wire into brain circuits
A team of researchers led by Pierre Vanderhaeghen and Vincent Bonin (VIB-KU Leuven, Université libre de Bruxelles and NERF) showed how human nerve cells can develop at their own pace, and form highly precise connections with the surrounding mouse brain cells.

Brain scans reveal how the human brain compensates when one hemisphere is removed
Researchers studying six adults who had one of their brain hemispheres removed during childhood to reduce epileptic seizures found that the remaining half of the brain formed unusually strong connections between different functional brain networks, which potentially help the body to function as if the brain were intact.

Alcohol byproduct contributes to brain chemistry changes in specific brain regions
Study of mouse models provides clear implications for new targets to treat alcohol use disorder and fetal alcohol syndrome.

Scientists predict the areas of the brain to stimulate transitions between different brain states
Using a computer model of the brain, Gustavo Deco, director of the Center for Brain and Cognition, and Josephine Cruzat, a member of his team, together with a group of international collaborators, have developed an innovative method published in Proceedings of the National Academy of Sciences on Sept.

Read More: Brain News and Brain Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.