Endless hours spent perfecting your golf swing or basketball shot could be a waste of time, according to a new study which shows that practice does not always make perfect.
Mark Churchland and colleagues at Stanford University in California, US, made the discovery after training macaque monkeys to repeat a simple reaching task thousands of times.
“The nervous system was not designed to do the same thing over and over again,” says Churchland, whose team investigated the way the brain plans and calculates motion.
The team showed the monkeys a coloured spot and rewarded them for reaching out to touch it at different speeds. During the exercise, they monitored the promoter cortex of the monkeys’ brains, which is the region responsible for movement planning, and tracked the speed of the resulting motion.
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Over the course of thousands of reaches, the monkeys rarely moved with exactly the same speed. Small variations in reach speed followed small variations in brain activity during movement planning, the researchers say.
Conventional wisdom
Contrary to conventional wisdom that movement variability is caused by muscle activity, Churchland’s team found that neural activity accounts for about half the variations. In other words, training muscles to perform a certain way through practice, such as countless hours teeing off or shooting a basketball, will not produce the same shot every time because the brain’s behaviour is inconsistent.
After an initial training period, the monkeys’ reach accuracy did not improve over time, suggesting that lots of practice can only improve movement control so much, says team member Krishna Shenoy.
The researchers speculate that humans and animals evolved with this “improvisational style” in response to the predator-prey dynamic where predators never catch and kill prey in exactly the same conditions.
“Premium athletes’ quest for consistency is a stark contrast to the way we evolved through history,” Shenoy says.
The team hopes that understanding the way the brain controls movement may lead to treatments for neurological conditions such as Parkinson’s disease, which is characterised by tremors.
Journal reference: Neuron (vol 52, p 1085)
![Astronomers have long known that understanding how star clusters come to be is key to unlocking other secrets of galactic evolution. Stars form in clusters, created when clouds of gas collapse under gravity. As more and more stars are born in a collapsing cloud, strong stellar winds, harsh ultraviolet radiation and the supernova explosions of massive stars eventually disperse the cloud, and their light can bear down on other star-forming regions in the galaxy. This process is called stellar feedback, and it means that most of the gas in a galaxy never gets used for star formation. Researching how star clusters develop can answer questions about star formation at a galactic scale. Now, the state of the art has been further developed with both Hubble and Webb working together to provide a broad-spectrum view of thousands of young star clusters. An international team of astronomers has pored over images of four nearby galaxies from the FEAST observing programme (#1783), trying to solve this mystery. Their results show that it is the most massive star clusters that clear away their gaseous shroud the fastest, and begin lighting their galaxy the earliest. The team identified nearly 9000 star clusters in the four galaxies in different evolutionary stages: young clusters just starting to emerge from their natal clouds of gas, clusters that had partially dispersed the gas (both from Webb images), and fully unobstructed clusters visible in optical light (found in Hubble images). With Webb???s ability to peer inside the gas clouds, they were able to then estimate the mass and age of each cluster from its light spectrum. This image shows a section of one of the spiral arms of Messier 51 (M51), one of the four galaxies studied in this work, as seen by Webb???s Near-Infrared Camera (NIRCam). The thick clumps of star-forming gas are shown here in red and orange, representing infrared light emitted by ionised gas, dust grains, and complex molecules such as polycyclic aromatic hydrocarbons (PAHs). Within these gas complexes, each tens or hundreds of light years across, Webb reveals the dense, extremely bright clusters of massive stars that have just recently formed. The countless stars strewn across the arm of the galaxy, many of which would be invisible to our eyes behind layers of dust, are also laid bare in infrared light. [Image description: A large, long portion of one of the spiral arms in galaxy M51. Red-orange, clumpy filaments of gas and dust that stretch in a chain from left to right comprise the arm. Shining cyan bubbles light up parts of the gas clouds from within, and gaps expose bright star clusters in these bubbles as glowing white dots. The whole image is dotted with small stars. A faint blue glow around the arm colours the otherwise dark background.]](https://images.newscientist.com/wp-content/uploads/2026/05/13114322/SEI_296271016.jpg)
