Monday 18 February 2013

Sensitive periods in music learning

Perhaps a little too young?

When people call to enquire about piano lessons, they often ask me what age is ideal for starting piano.  And my first answer is invariably:  it depends on the child.  There are a lot of factors that go into determining whether the time is right for beginning music lessons  But in general, I can say that earlier is better (up to a limit – three and a half is usually my cut-off on the early end).  Older children can learn faster than younger children, and so will “catch up” quickly, but there is general agreement among musicians and scientists that something is lost by waiting to begin music lessons.  As for learning languages, there seems to be a window in brain development during which we are more able to take in musical learning.

Windows in development:  sensitive and critical periods
A window in development like this is known to scientists as a sensitive period or a critical period.  A critical period is a time window during which, if the appropriate stimuli are not received, the brain does not develop properly, and will never be able to correctly process that type of stimuli.  The classic example was provided by the pioneering studies of Hubel and Wiesel in the 1960’s.  They showed that if kittens were prevented from seeing during a particular time window in development, the visual cortex did not develop properly.  Allowing the kittens to see later did not reverse this effect: once the window was closed, the visual cortex would never develop properly.  That time window is a critical period.

A sensitive period is a little more forgiving than a critical period.  If the appropriate input to the brain is not received during a sensitive period, input at a later date can have an effect, but to a lesser degree.  Studying language is like this.  There is a sensitive period that closes around the age of six, but you can still learn French as an adult; it’s just going to be a little harder and you might never be as fluent.

A window for musical brain development?
The question with respect to musical training is:  Is there really a sensitive period for musical brain development?  Scientific studies seem to support the idea that starting music lessons earlier is better, but it’s hard to separate out the effects of starting music lessons early from the effects of studying for longer.  After all, if you start music at four, then by the time you’re twenty, you’ve been playing for sixteen years, but if you start at twelve, you’ve only been playing eight years by the time you’re twenty.  So if scientists compare twenty-year-old musicians, are they analyzing the effects of starting early, or the effects of studying longer?

Researchers from Concordia University have tried to level the playing field (so to speak) in a new study that compares two groups of musicians who have been playing on average the same length of time:  one group that began lessons before the age of seven, and one group who began when they were older than seven.  Their results strongly support the idea that there is a sensitive period in the development of the brain that responds to musical training.  People who had begun musical training early in life had a greater connection between the two sides of the brain, particularly the connection between regions of the brain responsible for motor control and sensory input of the hands.  The early-musical-training group had more white matter in their corpus callosum, and (presumably because of this extra white matter) was better able to synchronize their hands, as shown in a behavioural tapping test.  There was also altered connectivity in the left temporal lobe, probably due to stronger ties between the auditory cortex and motor cortex.  These connections are key for sensorimotor integration, which is the way the brain forms links between the movements we make and the sensations that the movements produce.

From a neurological standpoint, beginning lessons before the age of seven is advantageous.  Does that mean that older children don’t really benefit from music lessons?  That idea is clearly ridiculous.  Many musicians (myself included) begin their training after the age of seven.  In fact, it’s possible that people who begin lessons later are more likely to truly enjoy playing music (and therefore are more motivated to practice): they are learning music because they want to, not because their parents have decided they should.  In any case, musical training at all ages has a multitude of benefits.  But, all other things being equal, why not start music lessons before the age of seven to take advantage of that sensitive period?

Steele, C.J., Bailey, J.A., Zatorre, R.J., and Penhune, V.B. (2013). Early musical training and white-matter plasticity in the corpus callosum: evidence for a sensitive period. J. Neurosci. 33, 1282–1290.