FORGET what your teachers said, practice doesn't make perfect.
At least it doesn't when you practise over and over again without a break.
Sydney scientists have found learning improves when students take a rest from continuous study or training.
''It seems intuitive that every minute of study should make you better, but, actually, if you do too much it might backfire and you end up wasting time,'' said the study's lead researcher, Joel Pearson.
To measure this effect, Dr Pearson, a cognitive neuroscientist at the University of NSW, had 31 students complete a computer screen test where they had to pick the direction of hundreds of moving dots.
''It looks a bit like a snow storm so it can be hard to see what direction they're moving at first, but it is a skill that can be learnt,'' he said.
On the first day of the experiment, one group of participants watched the moving dots for two hours without a break, while another group had one hour of down time between their study sessions.
When both groups repeated the task for an hour the next day, the researchers found the students who took time out between training improved, while the performance of the non-break participants remained the same.
''If you keep on learning for multiple hours in a row without a break you don't get the [learning] benefit any more,'' said Dr Pearson.
When learning something new the brain must convert a short-term memory into a long term memory for the skill to persist.
While scientists have known this process of memory consolidation occurs during sleep, Dr Pearson and his colleagues are the first to show it can also happen when awake.
Many scientists believe the brain consolidates a new skill by making new connections between neurons, a re-wiring process known as neural plasticity.
Continued practice appeared to disrupt this consolidation process, he said.
While the study reviewed a particular type of learning known as perceptual learning, which occurred when reading or learning to interpret an X-ray, the same processes arose when a person learnt to ride a bike or tried to grasp a new concept, said Dr Pearson, whose findings are published in the journal Proceedings of the Royal Society B.