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?

 

Reference:

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.

 

Feeling the Beat

It’s a Thursday morning, and I’m leading a Music Circle Time at the local drop-in playcentre.  The kids are enthusiastic and adorable: mostly one- and two-year-olds, some infants, and a handful of older preschoolers, all eager to sing, dance, jump, twirl, tap and shake.  I run through a repertoire of fun songs that all involve some kind of movement.  Even for sit-down songs with no obvious actions (like “Old MacDonald had a Farm”, for example), we clap or tap to the beat.  This keeps the kids engaged, but more importantly, it activates their sense of rhythm.  Literally, they “feel” the beat of the music.

If you stop to think about this phrase, “feeling the beat”, you might find it a bit odd.  Listening to music is something we do with our hearing, not our sense of touch, right?  Surely we don’t actually feel the beat any more than we can smell the colour in a painting.  In fact, that’s not entirely true.  A recent study (Huang et al., 2012) published in PLoS ONE looked at how we use different senses to “feel” the beat in music, and found that we can perceive musical beat and meter with both hearing and touch, and not only that, but the two types of sensory information are integrated together in the brain. 

Before we get into this, let me explain what I mean by meter.  Music almost always has a regular beat to it, and when we listen to these beats, we hear them grouped into patterns of strong beats and weak beats.  A slow waltz, for example, will have a pattern of strong - weak - weak, strong - weak - weak, etc.  This is known as triple meter.  A march would have a pattern of strong - weak - strong - weak; this is duple meter.  Studies have shown that even if the music is generated such that it doesn’t actually contain strong and weak beats, people will impose a meter upon the music and think of it as either duple or triple meter.

In the Huang study, the subjects had to identify whether they thought the meter of a rhythm was duple or triple.  This identification was based either on the pattern of accents put into the rhythm (i.e. some beats were made to be louder and sound or feel like strong beats), or based simply on whether there was generally a note or a rest where we would expect the strong beat to be.  The subjects were able to tell easily whether the rhythm was duple or triple when the rhythm was presented as an audible series of notes (i.e. using hearing) or when the rhythm was presented as a series of taps on the subject’s hand (i.e. using touch).  This is not a new result – previous studies have shown that we are quite good a recognizing rhythm using touch (although, interestingly, not with vision).  

Where this new study showed something really interesting was when the subjects had to recognize the meter using both hearing and touch.  In this part of the experiment, some of the beats were presented as audible notes, and some of the beats were presented as taps on the hand.  The subjects had to integrate both modalities in order to identify whether the meter was triple or duple.  And the study showed that they could, although it was easiest to identify the meter if all the strong beats were presented in a single modality, e.g. all the strong beats were taps on the hand and the weak beats were audible notes.  If the two different modalities of sensing rhythm were given information that interfered with each other (i.e. the notes going to touch felt like duple meter, and the notes going to hearing sounded like triple meter), the subjects had a much harder time figuring out what meter the combined rhythm was in, showing that the two types of inputs interact to a great extent.  The auditory information tends to be dominant, having a greater influence on meter perception than touch.

This study reminds me of a classic paper published in the journal Science in 2005, from Laurel Trainor’s lab.  This classic study used metrically ambiguous music (i.e. could be interpreted as duple or triple), and had infants bounced to the beat in either two or three.  Then the music was played back to the infants with accents added so that it was clearly either in duple or triple meter, and the infants preferred the meter in which they had been bounced.  The researchers concluded that this effect was probably due to vestibular (balance) input interacting with auditory input.  The main point was that body movement plays an important role in rhythm perception.

All of this suggests that in order to help students with their rhythm and meter, we should take advantage of the integration of auditory musical information with movement and touch sensation.  This works just as well with older students as it does with my little ones at the playcentre.  The more senses we can enlist to help students feel the beat, the better.

For instance, the teacher could play the piece while the student marches, bounces, dances or moves in some way to the beat.  With younger children, the parents can bounce them on the strong beats.  This leaves the movement to someone who presumably can feel the meter.  Having the children move on their own may be useful but if they are not feeling the beat already, asking them to move may not improve it.  There are other options, rather than having the students get up and move:  the student could sway to the beat while playing, or nod their head.  Movement of the head strongly activates the vestibular system, so this is probably a better reinforcer of meter than having the student just tap their foot.  That being said, clapping and tapping are also useful, although having the student move their whole leg (“walking” their feet while sitting down) is more effective than just tapping, since the bigger the movement, the better.  The teacher or parent could also tap the beat on the student’s shoulder while they are playing, remembering to accent the strong beats.  In this way, they are receiving both touch and auditory information about the meter.

I’m sure there are many other ways to incorporate touch and balance into our daily interactions with music.  I’d be interested in other ideas – please share what works for you!

References:

Huang, J., Gamble, D., Sarnlertsophon, K., Wang, X., and Hsiao, S. (2012). Feeling Music: Integration of Auditory and Tactile Inputs in Musical Meter Perception. PLoS ONE 7, e48496.

Phillips-Silver, J., and Trainor, L.J. (2005). Feeling the Beat: Movement Influences Infant Rhythm Perception. Science 308, 1430–1430.

Learning in Your Sleep

Imagine climbing into bed, turning off the light, and shutting your eyes.  As you drift off to sleep, a small machine monitors your brainwaves, and when it indicates that you have entered a stage of deep rest known as slow-wave sleep, a Mozart sonata begins to play softly.  You’ve spent a solid hour practicing this sonata during the day, and while it plays repeatedly during your slumber, the memory trace laid down in your brain during that practice session becomes reactivated in both the auditory and motor parts of the brain.  In the morning, unaware of your nighttime “practice session”, your performance of the sonata is significantly improved.

I would normally be highly skeptical of this type of claim.  It reminds me of that scene in Huxley’s Brave New World where children listen to history lessons in their sleep, instead of having to go to school.  It sounds like new age mumbo-jumbo to me.

Except that this exact type of learning effect has been shown by researchers at Northwestern University and published in this month’s issue of Nature Neuroscience.  The experiment was straightforward:  Sixteen people learned to play two short melodies on the piano, and then had a 90 minute nap.  When they entered slow-wave sleep, one of the melodies was quietly played twenty times.  After the nap, performance on the melody that had been played during the nap was significantly improved compared to the melody that wasn’t played.

This study brings together two interesting aspects of music learning.  The first is the role of sleep in aiding learning.  Previous studies have shown that memory consolidation during sleep is an important source of improvement between practice sessions. The second aspect is the importance of sensorimotor integration in learning to play an instrument.  During practicing, our brains learn to associate the sounds we produce (the auditory feedback) with the movements that lead to those sounds. The auditory and motor parts of our brains become more highly linked, so that just hearing a song that we know how to play activates motor parts of the brain, and just making the movements associated with playing a song (like pressing the keys of an unplugged keyboard) causes auditory parts of the brain to light up.  This is why hearing the music in our sleep can cause improvements in our motor performance:  the replaying of the song reactivates the auditory memory, which simultaneously reactivates the motor memory, strengthening both these memories and their association with each other.

So, am I going to start listening to piano music in my sleep?  I’m certainly considering giving it a try.  There are a few possible caveats to the potential gains here.  First, music might interfere with sleep.  In the research study, there were a couple of subjects who did wake up while the music was playing, so this could definitely be a downside.  Another issue to consider is that the music should probably be played during slow-wave sleep, as it was in the research study, to have maximum effect (although the effects of playing music during other stages of sleep have yet to be examined).  Most people (myself included) don’t keep track of when they are in deep sleep.  However, there are iphone apps that claim to monitor stages of sleep (usually these aim to waken you during light sleep) and these could potentially be adapted to trigger music during deep sleep.  A third issue is that the effect on music motor learning might simply be a bias instead of an absolute gain in learning.  What this means is that listening to one song might improve performance on that song at the expense of other songs being learned.  In the research study, the melody that was played during sleep improved 7.9%, while the other melody only improved 2.6%.  Meanwhile, for people who didn’t have either melody played during their sleep, both melodies improved about 4.4%.  Perhaps there is a limit to how much improvement can happen during sleep: listening to the one melody caused it to be improved but maybe also caused the other melody to improve less.

In any case, it sounds like a fun summer project and I do have a couple of piano pieces I’m trying to learn, so why not?  Sweet dreams!

Reference:

Antony, J.W., Gobel, E.W., O’Hare, J.K., Reber, P.J., and Paller, K.A. (2012). Cued memory reactivation during sleep influences skill learning. Nature Neuroscience 15, 1114–1116.

Effort

Whew!  May and June are crazy months for me.  As the end of the school approaches, it’s time to focus on finishing up my piano classes for the summer.  Last weekend saw my year-end piano recital, and this week I teach my last classes and lessons, except for those students who have exams at the end of June.  In addition, these months are the time when I have to look after my least favourite part of music teaching:  the shameless self-promotion, trying to fill my new classes for the fall.  My musical theatre group’s summer show opens in two weeks (unbelievably soon!), and I am scrambling to memorize lines and master dance steps.  And on top of all that, it’s time for me to start preparing for the summer university course that I teach, “Elements of Neuroanatomy and Neurophysiology”.  I’ve been lining up guest lecturers, comparing textbooks, and starting to review my notes and presentations. 

All of this is by way of explanation for the recent dearth of posts here on my blog.  I have a post that’s been two-thirds finished for weeks now, and I really will get around to those last few paragraphs soon.  And since I’m in the process of reviewing all of neuroanatomy, you can expect posts this summer discussing specific areas of the brain, how they work, and their role in music-making.

In the meantime, I wanted to point out this excellent blog post by Jonah Lehrer (whose fascinating new book “Imagine” is one of several that I am halfway through reading).  His post describes a new research paper looking at what parts of the brain are active when we are deciding whether or not a task is worth the effort we are expending.  I won’t describe the research in any detail, because Lehrer does such a good job, but it turns out that there are specific parts of the brain (left striatum and ventromedial prefrontal cortex) that receive more dopamine in people who are more willing to persist with a difficult job, and different parts of the brain (the insula) that receive more dopamine in people who give up easily.

This observation struck a chord with me because I’ve been busy researching about the topic of “Motivation and the Brain” for a talk I will be giving to the B.C. Music for Young Children teachers in the fall.  The question of how to motivate students and encourage them to practice well and regularly is a never-ending one for most music teachers.  My experience as a teacher and a parent has been that the hardest challenge that students need to overcome is their own desire to just go and do something easier.  Practicing music is hard work, and the immediate rewards may be small, so it’s hard for students to stick with it, every practice session.  But it’s harder for some than for others.  Even between my own two children, the difference in “stick-to-it-iveness” is astonishing, and directly related to their different levels of success at playing the piano.  What I find remarkable is that we can now relate this aspect of personality to levels of neurotransmitters in specific parts of the brain.

The more important issue, to my mind, is whether there’s anything we can do to encourage the growth of persistence as a personality trait.  Can we learn to have higher levels of dopamine in the appropriate structures in the brain?  Perhaps if we can wheedle kids into practicing enough, they will learn to see the connection between the work and the reward; the neurons in the reward pathway will become rewired to reinforce those parts of the brain making the decision about whether practicing is worth the effort.  Certainly children can become more willing to work hard over time, but it’s difficult to know how much of that is learned and how much is simply brain development with age.  My nine-year-old is much more focused and hard-working about her piano practice than she was several years ago, but I’m pretty sure it’s not because of anything I’ve done to encourage her; she’s simply older than she was.

It’s something to ponder, and I’ll definitely have more to say here about motivation before I’m ready to give my talk in the fall.

Music for the Little Ones

Am I ready for piano lessons?

I’ve been asked before, many times, at what age I think children should start musical training.  And I know that what people are really asking is “When should we start piano lessons?”  But really, musical training starts as soon as a child is able to hear: in utero, before the child is even born.  Because the initial part of musical training is all about listening to music.  A baby’s brain is learning how to make sense of sounds.  This is true for speech, environmental sounds, and, of course, music.  It’s unclear how much babies can hear in the womb, or what sense they make of sounds, but babies are certainly born able to understand pitch and rhythm.  And as they listen to music over the first few years of their lives, they become “enculturated”, meaning they learn to recognize and enjoy the basic norms of the music of their culture.  For example, children enculturated to Western music prefer tonal music over atonal, and can recognize when out-of-key chords are inserted into songs.

Baby Music Classes?
But what about taking actual music classes – at what age is that really worthwhile?  Should parents just listen to music at home with their infants and toddlers, or is there extra benefit from taking a music class?  A recent paper from Laurel Trainor and colleagues at MacMaster University in Ontario describes research showing that babies gain a lot from participating in music classes.  The 6-month study looked at infants who were 6 months old at the beginning of the experiment, and 12 months old at the end.  The babies were split into two groups:  one group participated, along with their parents, in a music class (including movement, singing, and playing rhythm instruments), while the second group participated (again with their parents) in a play-based class where music was playing in the background.

This study showed three main results:

1) The babies who had attended the music class for six months more strongly preferred tonal music over atonal music compared to babies in the play class.  This indicates that music classes had helped the babies become more enculturated; they had a better understanding and preference for Western tonal music than the other babies.

2) Musical tones were processed differently by the brains of babies who had attended music class.  This was shown by EEG recordings, which use electrodes pasted on the babies' heads to measure brainwave activity.  Actively participating in a music class led to the babies being better able to process musical sounds.

3) Parents of babies who had attended the music class reported that their children had more positive social interaction with them, were easier to soothe, and showed more smiling and laughter, compared to reports from parents whose babies participated in the play classes.

 Definitely ready for rhythm instruments

Wednesday mornings are one of my favourite times of the week.  I teach a class called Music Pups, in which I get to sing, dance, twirl, jump, play rhythm instruments and just be generally silly, with a group of adorable little ones and their happy parents.  I’ve been teaching this class for years, ever since my son was a baby, and I love it.  So I didn’t need to read a research paper to convince me that music classes for infants are worthwhile.  Even the littlest ones babble along with the music, and shake instruments, and laugh and coo when their mothers dance with them.  The class is designed for a mixed age: babies to four-year-olds.  I’ve had children who have taken the classes over a number of years and so I’ve been able to watch their musical development.  It’s amazing to see these toddlers begin to sing along easily with their favourite songs, to echo back (on pitch!) little musical phrases, and to beat their drums in time to the music.  Some of these kids are now my piano students and it’s obvious that the early music classes give them an edge.  But more than that, this type of music class helps reinforce a love for music and give the children an early taste of what music teachers really want to impart to their students:  the joy of music-making.

Reference

Trainor, L.J., Marie, C., Gerry, D., Whiskin, E., and Unrau, A. (2012). Becoming musically enculturated: effects of music classes for infants on brain and behavior. Annals of the New York Academy of Sciences 1252, 129–138.

Linking movement and sound

Lately my 6-year-old has been difficult about his piano practice.  His new trick goes like this:  I say something along the lines of, “Okay, why don’t you start with The Wild Horseman today?”

He shoots me a rebellious look and replies. “Fine, I’ll play The Wild Horseman”.  He puts his hands in the correct starting position, and proceeds to sing the entire song, note perfect, while moving his fingers over the correct keys, but not pressing them down.  He then grins saucily at me.

I put on my “mom” voice.  “Very funny.  Now play it properly, with your fingers, not your voice.”  What I don’t tell him is that this is actually not a half-bad way of practicing. 

Practice forms mental representations of the music

When we practice music what we’re actually doing is forming a mental representation of the song.  When we play it for the first time, we read it note-by-note (or maybe chord-by-chord, if we’re more experienced), but as we practice, we stop having to focus on the individual notes, and instead they become encoded in our brain as a whole sequence of notes. Once we have practiced the song enough, we just have to start it, and the notes  follow one another, like beads on a string. This is true for both the movements we make while playing and the sounds that are produced, because we form both a motor representation of the song AND an auditory representation of the song.  That is, we learn the movements we need to make, and we learn what the song sounds like.  These two representations are closely tied together in our brains and they support each other.  Scientists have a special name (don’t they always?) for this connection between the movements we make and the sensations that are produced: “sensorimotor integration”.

Imagine playing your favourite piece of music on an electronic keyboard.  Now imagine playing it with the keyboard turned off, so there is no sound.  It would be much harder, wouldn’t it?  We need that auditory feedback to help keep our motor program running properly.  In fact, the best way to hit all the right notes on the soundless keyboard is to play a mental soundtrack of the song while performing the movements.  This works because the parts of our brain that store and produce the motor pattern are intricately linked to the parts of our brain that listen to the sounds we produce by playing.  And these auditory parts of the brain are activated during mental imagery of music.

The connection between movement and sound works the other way around too.  It’s been shown that if you are listening to a piece of music that you know how to play, motor parts of your brain are activated, as if you were playing along.

Sensorimotor integration aids musical memory

A recent paper from McGill University explores the role of sensorimotor integration in musical memory.  The researchers, Rachel Brown and Caroline Palmer, had pianists learn short melodies in one of four different ways:  1) by simply listening to them, 2) by practicing the songs on a soundless keyboard  3) by practicing them on a keyboard with sound or 4) by practicing them along with recorded version of the songs, but unable to hear their own playing.  The pianists were then tested to see whether they recognized the melodies from among a pool of other melodies they had to listen to.  Pianists were also tested to see how good their auditory and motor imagery was. 

The researchers found that practicing without any auditory feedback (i.e. on a soundless keyboard) made it quite hard to recognize the melodies after.  It was much worse than normal practicing (which was the best), practicing with a recording (2^nd best), or just listening to the tunes (3^rd best).  However, pianists with good auditory imagery were the most successful at recognizing melodies they had practiced without sound.  In other words, if the pianists were better at mentally “singing along” with their soundless practice, they were better able to recognize those tunes later.

Direct auditory feedback makes for the strongest sensorimotor associations

Another interesting result from this paper came from comparing practice where the movements and sounds were either “strongly coupled” or “weakly coupled”.  Strongly coupled meant that the pianists could hear their own playing, so there was a complete and direct connection between the movements the pianists made and the sounds they heard.  In weakly coupled practice, the pianists could not hear their own playing, but they heard a recorded version of the melody.  What this meant was that as long as they played exactly correctly (in terms of both pitch and rhythm), the sounds they heard were connected to the movements they made.  But if they hit the wrong key on the keyboard or were a little slow in their rhythms, this was not reflected in the sounds they heard.  What the researchers found was that strongly coupled practice made for stronger memories of the melodies than weakly coupled practice.  The conclusion was that direct feedback of the effects of the movements seemed to be required for the strongest auditory-motor associations. 

Practicing the mental representation 

My son, while intending to be silly, is practicing his mental representation of the melody by singing it.  And moving his fingers at the same time practices his representation of the motor task of playing the song.  What’s lacking is the direct feedback: if he makes a mistake with his fingers, it won’t result in a wrong note in his singing.  So if he makes a lot of mistakes, this isn’t going to help his motor representation.  But since in this case he’s playing a song that he actually knows quite well, it’s not a terrible way to practice (and certainly better than not practicing at all!)

Another way to think about this type of “practicing” is that it’s a good way to warm up the brain for the physical practicing of this song.  In fact, a really good warm-up might just be to sit and look over the music and imagine playing it, thinking about how the hands would move and what the song would sound like.  This is mental practicing… but I think that’s a topic for another post.

Reference:

Brown RM, Palmer C. Auditory–motor learning influences auditory memory for music. Memory & Cognition. 2012. Available at: http://www.springerlink.com/index/10.3758/s13421-011-0177-x. Accessed April 23, 2012.

Cellular Mechanisms of Learning

In a comment on a recent post, BusyB asked if I had read the book The Talent Code by Daniel Coyle.  I had not at the time, but quickly requested it from the good ol’ Vancouver Public Library.  The author has a pretty straightforward premise:  to get good at something, you have to engage in what he calls “deep practice”, and this increases your talent by causing the growth of myelin in your brain.

What do I think about this?  I’ll talk about talent and practice (and the inevitable nature-vs-nurture question) at a later date, but today I want to talk about what happens in our brain when we learn something.  Let me say right off that I find Coyle’s claim that skill-building equals myelin growth such a gross oversimplification that I literally cringed every time myelin was mentioned.  The book was peppered with repeated sentences such as “Skill is myelin insulation that wraps neural circuits”.  And, really?  It’s just not that simple.  Sorry.

Let me back up and tell you a little bit about neurons and synapses and myelin and what we think happens to them during learning.

Neurons in a nutshell

You probably know that neurons are brain cells, and you have billions of them in your head and spinal cord.  Neurons “talk” to one another electrically through specialized connections called synapses.  Here’s a schematic view of two neurons (one blue, the other green) connected by a couple of synapses.

The axon is the part of the neuron that carries electrical impulses away from the cell body.  At the end of the axon, there are specialized endings where the electrical signal gets transferred onto the dendrites of another neuron.  These are the synapses.  In most neurons, the axon is wrapped up in an electrical insulator made of a substance called myelin.  Electrical impulses travel faster down axons that are insulated, and so the presence and amount of myelin on an axon alters the neuron's ability to transmit electrical signals.

Learning makes stronger connections between neurons

That’s, in a very small nutshell, how neurons work.  And although I’ve only shown two neurons in my diagram, every neuron is connected to many, many other neurons, forming a complex spider’s web of neuronal circuits.  Almost everything that happens in our brains comes down to circuits of neurons transmitting electrical signals.  So when we learn something new, or get better at doing something, what happens in our brains is that the neuronal circuits responsible for that fact or skill become stronger, better able to communicate with one another. 

There are several main ways in which this can happen:

1)  The synapses themselves become stronger and so transmit the signals more reliably

2)  New synapses form, so the neurons are more strongly connected

3)  Myelin growth leads to faster transmission of the electrical signals down the axon, and better timing of neuronal signals.

The synaptic mechanisms (numbers 1 and 2 above) have been studied in excruciating detail (or at least that's how it feels to people like me who have spent years in nitty-gritty synaptic research) and scientists as a group are slowly getting a handle on how changes in synapses happen and how this helps us learn things. 

Neurons that fire together wire together

Here’s how scientists think that learning works:  The basic idea is that every thought is encoded by the firing of a specific group of neurons, all connected in a circuit.  So a particular circuit fires when we think of the note middle C, for example.  And there’s another circuit that fires when we picture a note on the first ledger line below the treble clef staff.  When we learn that this position on the staff corresponds to middle C, both of these circuits fire at the same time.  And when neurons fire at the same time, the connections between the neurons get stronger.  The synapses get stronger, and/or new synapses form.  This means that the next time we fire the circuit that means “note on the first ledger line below the staff”, the circuit that corresponds to “middle C” is more likely to fire.  Neuroscientists have a saying for this:  "Neurons that fire together wire together”.  From a learning standpoint, it means that we have learned to connect those two ideas by physically altering the way the neurons in our brain are connected.

These changes in synaptic strength very clearly happen when we learn something, whether new facts or new skills.  Synaptic changes are an important part of learning during development, and relearning following brain injury.  There is a ton of research showing this.  The fact that Coyle doesn’t even mention these types of mechanisms as taking place during learning is kind of ridiculous.

Myelin and Learning
So what about myelin?  Does myelin growth aid in skill learning, as Coyle purports?  The answer, based on scientific research, is “probably”.  There are correlational studies showing that people who are more skilled at certain tasks (like reading, or playing music) have greater myelination in areas of the brain related to those tasks.  In particular, musicians have a larger and more myelinated corpus callosum, the axon bundle that connects the two halves of the brains.  This is especially true for musicians who began their musical training before the age of 7, which makes sense, because the myelination of the nervous system is something that occurs throughout childhood and is not complete until a person is in their mid-twenties.  Myelination of neurons during learning in adults is still a controversial idea, and research in this area is on-going.  I’m interested in this line of research, especially the thought that the amount of myelin helps to co-ordinate the arrival of signals from different neurons.  Perhaps myelination plays a greater role in learning of skills compared to learning of facts (implicit vs. explicit learning), but I was not able to find any evidence for this in the scientific literature.

What do I think about The Talent Code?  I agree with the (rather obvious) idea that hard works leads to the acquisition of skills, but I think there are better and more interesting books that address this topic (this one, for example).  However, I think the scientific side of his book is weak, oversimplified and kind of misleading.

References

Bengtsson SL, Nagy Z, Skare S, Forsman L, Forssberg H, Ullen F. (2005) Extensive piano practicing has regionally specific effects on white matter development. Nat. Neurosci. 8(9):1148-1150.

Fields RD. (2008) White matter in learning, cognition and psychiatric disorders. Trends Neurosci. 31(7):361-370.

Schlaug G, Jäncke L, Huang Y, Staiger JF, Steinmetz H. (1995) Increased corpus callosum size in musicians. Neuropsychologia. 33(8):1047-1055.

Ullén F. (2009) Is activity regulation of late myelination a plastic mechanism in the human nervous system? Neuron Glia Biol. 5(1-2):29-34.