Using a deceptively simple set of experiments, researchers at Johns Hopkins have learned why people learn an identical or similar task faster the second, third and subsequent time around. The reason: They are aided not only by memories of how to perform the task, but also by memories of the errors made the first time.
“In learning a new motor task, there appear to be two processes happening at once,” says Reza Shadmehr, Ph.D., a professor in the Department of Biomedical Engineering at the Johns Hopkins University School of Medicine. “One is the learning of the motor commands in the task, and the other is critiquing the learning, much the way a ‘coach’ behaves. Learning the next similar task goes faster, because the coach knows which errors are most worthy of attention. In effect, this second process leaves a memory of the errors that were experienced during the training, so the re-experience of those errors makes the learning go faster.”
Shadmehr says scientists who study motor control — how the brain pilots body movement — have long known that as people perform a task, like opening a door, their brains note small differences between how they expected the door to move and how it actually moved, and they use this information to perform the task more smoothly next time. Those small differences are scientifically termed “prediction errors,” and the process of learning from them is largely unconscious.
The surprise finding in the current study, described in Science Express on Aug. 14, is that not only do such errors train the brain to better perform a specific task, but they also teach it how to learn faster from errors, even when those errors are encountered in a completely different task. In this way, the brain can generalize from one task to another by keeping a memory of the errors.
To study errors and learning, Shadmehr’s team put volunteers in front of a joystick that was under a screen. Volunteers couldn’t see the joystick, but it was represented on the screen as a blue dot. A target was represented by a red dot, and as volunteers moved the joystick toward it, the blue dot could be programmed to move slightly off-kilter from where they pointed it, creating an error. Participants then adjusted their movement to compensate for the off-kilter movement and, after a few more trials, smoothly guided the joystick to its target.
In the study, the movement of the blue dot was rotated to the left or the right by larger or smaller amounts until it was a full 30 degrees off from the joystick’s movement. The research team found that volunteers responded more quickly to smaller errors that pushed them consistently in one direction and less to larger errors and those that went in the opposite direction of other feedback. “They learned to give the frequent errors more weight as learning cues, while discounting those that seemed like flukes,” says David Herzfeld, a graduate student in Shadmehr’s laboratory who led the study.
The results also have given Shadmehr a new perspective on his after-work tennis hobby. “I’m much better in my second five minutes of playing tennis than in my first five minutes, and I always assumed that was because my muscles had warmed up,” he says. “But now I wonder if warming up is really a chance for our brains to re-experience error.”
“This study represents a significant step toward understanding how we learn a motor skill,” says Daofen Chen, Ph.D., a program director at the National Institute of Neurological Disorders and Stroke. “The results may improve movement rehabilitation strategies for the many who have suffered strokes and other neuromotor injuries.”
The next step in the research, Shadmehr says, will be to find out which part of the brain is responsible for the “coaching” job of assigning weight to different types of error.
Other authors on the paper were Pavan A. Vaswani and Mollie K. Marko of the Johns Hopkins University School of Medicine.
This work was supported by the National Institute of Biomedical Imaging and Bioengineering (grant number T32EB003383), the National Institute of General Medical Sciences (grant number T32GM007057) and the National Institute of Neurological Disorders and Stroke (grant numbers R01NS078311 and F31NS079121).
Shawna Williams | newswise
How Humans and Machines Navigate Complex Situations
19.11.2018 | Max-Planck-Institut für Bildungsforschung
A gene activated in infant and young brains determines learning capacity in adulthood
13.11.2018 | Universitätsklinikum Hamburg-Eppendorf
In a joint experimental and theoretical work performed at the Heidelberg Max Planck Institute for Nuclear Physics, an international team of physicists detected for the first time an orbital crossing in the highly charged ion Pr⁹⁺. Optical spectra were recorded employing an electron beam ion trap and analysed with the aid of atomic structure calculations. A proposed nHz-wide transition has been identified and its energy was determined with high precision. Theory predicts a very high sensitivity to new physics and extremely low susceptibility to external perturbations for this “clock line” making it a unique candidate for proposed precision studies.
Laser spectroscopy of neutral atoms and singly charged ions has reached astonishing precision by merit of a chain of technological advances during the past...
The ability to investigate the dynamics of single particle at the nano-scale and femtosecond level remained an unfathomed dream for years. It was not until the dawn of the 21st century that nanotechnology and femtoscience gradually merged together and the first ultrafast microscopy of individual quantum dots (QDs) and molecules was accomplished.
Ultrafast microscopy studies entirely rely on detecting nanoparticles or single molecules with luminescence techniques, which require efficient emitters to...
Graphene, a two-dimensional structure made of carbon, is a material with excellent mechanical, electronic and optical properties. However, it did not seem suitable for magnetic applications. Together with international partners, Empa researchers have now succeeded in synthesizing a unique nanographene predicted in the 1970s, which conclusively demonstrates that carbon in very specific forms has magnetic properties that could permit future spintronic applications. The results have just been published in the renowned journal Nature Nanotechnology.
Depending on the shape and orientation of their edges, graphene nanostructures (also known as nanographenes) can have very different properties – for example,...
Using a clever technique that causes unruly crystals of iron selenide to snap into alignment, Rice University physicists have drawn a detailed map that reveals...
University of Texas and MIT researchers create virtual UAVs that can predict vehicle health, enable autonomous decision-making
In the not too distant future, we can expect to see our skies filled with unmanned aerial vehicles (UAVs) delivering packages, maybe even people, from location...
03.12.2019 | Event News
15.11.2019 | Event News
15.11.2019 | Event News
11.12.2019 | Materials Sciences
11.12.2019 | Information Technology
11.12.2019 | Life Sciences