Thursday 26 April 2012

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 (2nd best), or just listening to the tunes (3rd 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.

Brown RM, Palmer C. Auditory–motor learning influences auditory memory for music. Memory & Cognition. 2012. Available at: Accessed April 23, 2012.

1 comment:

  1. This is what we're finding with HearFones, that give singers 'strongly coupled' feedback of the sounds they're making at their mouth. The new higher-frequency "details" they hear seem to immediately cause them to correct and eliminate them, and consequently to internalize these new techniques. I really look forward to reading your reference paper.

    We've also heard your 6-year-old effect: put HearFones on the 10 kids in a childrens choir and the "kids singing" sound goes away. We get 10 young voices beautifully singing on pitch and with lovely voices. Amazing!