Mummy, how often do I have to practise?

With your child's weekly piano lesson coming round (or violin or oboe or whatever), the inevitable debate rears its ugly head about "how often have you practised this week?". Sadly, classical music demands many hours of practice: even international stars seem to spend a terrifying proportion of their waking hours practising, regardless of how much native talent they have.

The answer to the question "how much practice do I need" depends largely on what standard you want to achieve. If you just want to learn a bit about the instrument and become competent to play a few pieces nicely, you'll get away with an hour or three a week. If you want to play in a band or orchestra without making a fool of yourself, you'll need more. But how much do you need to become a real expert, a world-class performer?

Dan Levitin, author of "This is your brain on music", has an answer: about ten thousand hours. Levitin is a neuro-scientist at the very prestigious McGill University in Canada (and former session musician, sound engineer and record producer) who has been studying the science of musical perception for many years. Ten thousand hours is equivalent to about three hours a day for nine years. If you're Mozart, Levitin reasons, you might well have started at age two and clocked up thirty-two hours a week (under the tutelage of a proverbially rigorous father), in which case you will have got to ten thousand by about age eight - the age at which Mozart wrote his first symphony.

Interestingly, according to Levitin, the ten thousand figure shows up repeatedly in scientific studies of many different walks of like, ranging from basketball players to concert pianists to master criminals. It seems that becoming truly world class at something takes around the same amount of time - which is probably a function of the length of time that the most motivated of your competitors are prepared to put in. Of course, just notching up the hours isn't enough: you have to ensure that you're fully engaged and concentrating.

So now you know what you're up against...

The book isn't exactly a snappy read for a non-scientist - it's fairly heavy on the brain structure and chemistry - but it's well worth the effort: full of fascinating insights into the effect that music has on us, and why different people react so differently to all sorts of musical styles. In spite of what is basically a rock'n'roll background, Levitin is encyclopaedic about many different types of music, from Western classical to rock and jazz and even Indian ragas.

Here's one snippet that particularly took my fancy:

I've always felt that music is terribly, terribly important to me, without ever quite understanding why. Now, at least, I now that I'm in good company...