Hands Together

Not long after I started writing this blog, I received an email from one of my piano moms asking why it is that we always start by learning new songs “hands-separately”.  That is, I usually tell the kids to learn the right hand part and the left hand part separately before they try to play them both at the same time.  This mom is an occupational therapist and, as such, part of her job is to help people learn or relearn movements.  And she knows that there is a whole field of research showing that when we practice only a part of a movement task, or when we practice a movement out of context, it doesn’t always translate to good performance of that movement in the whole task.  What this means for pianists is that playing the right hand by itself is not really the same as playing the right at the same time as the left hand.  So why do we practice hands-separately?  To be honest, I have my students practice like this because that’s the way I learned to play the piano.  Practicing songs hands-separately is standard procedure for pianists, but is it really the best way?

Splitting our attention

There are two different aspects to playing hands-together that make it particularly difficult.  The first is that when we play piano with both hands, the right hand part and the left hand part are competing for our limited attentional resources.  For each hand, we have to figure out what key(s) on the piano to play and what rhythm to play for each note, in addition to details like dynamics and articulation.  There’s only so much attention to go around, so it’s hard to focus on all of that for both hands.  Attention is a key part of learning, so if we split our attention between the two parts, they will be harder to learn than if we practiced just one part at a time.  That is, it might take longer to learn the piece if we only practice hands-together, because we just can’t focus on all the individual details.  If we are learning only one part at a time, there is still lots to focus on, but it’s more manageable than trying to spread our attention among all those different aspects of the music for two separate piano parts.  Once we’ve learned one part on its own, it becomes more automatic, and we don’t have to use as much attention while we’re playing it.  So from this point of view, it absolutely makes sense to learn each hand’s part separately, and then put them together.  And this is clearly why the hands-separate approach is so popular.

Inhibiting the other hand

The second thing going on when playing hands-together is interhemispheric communication.  In general, the left side of the brain controls the right hand, and the right hemisphere of the brain controls the left hand.  However, the two hemispheres talk to each other, and what usually happens is that one hemisphere inhibits the other.  When we play with our left hand, our right motor cortex is active, and it not only sends motor commands to our left hand, but it also sends commands to the left motor cortex, telling it not to move the right hand.  And vice versa when we play with our right hand.

 This occurs because humans have a natural tendency for mirror movements:  when one hand moves, the other hand automatically mirrors its movements. This is seen in infants and young children, but as we develop motor control, we learn to stop these mirror movements:  the motor cortex of each side of the brain gives off axons that travel through the corpus callosum (the thick fiber band that connects the two sides of our brains) to inhibit the motor cortex of the other side.  This interhemispheric inhibition is particularly pronounced when we’re only using one hand.  In other words, if we are playing the piano with only one hand, our motor cortex is inhibiting the motor cortex of the opposite side.  So, if we’re practicing only the right hand part of a piano piece, we’re probably learning to inhibit the left hand.  And when we learn the left hand part by itself, we’re probably learning to inhibit the right hand.  Is it any wonder then, that when we go to play the song hands-together, it’s still really difficult?  Perhaps all this hands-separate practice is a little bit counterproductive.

So, hands-separately or hands-together?

The question, from a practical standpoint, is how do we balance these two issues?  Do we learn our songs hands-separately first so we can maximize our attention on each part while we’re learning them, or do we learn them hands-together from the beginning so that we can minimize interhemispheric inhibition?

Research that specificially addresses this issue is surprisingly scarce.  There are a couple of old, old music studies that do look at exactly this question:  Is it better to learn piano pieces hands-separately or hands-together? 

Hands-together practice is more efficient

In a self-study published in 1933, Roberta Brown learned 3 pairs of piano pieces.  In each pair, she learned one piece by starting hands-separately, and one by practicing hands-together.  She found that it was more efficient, and also more enjoyable, to practice using the hands-together method.

Rubin-Rabson’s study from 1939 also concluded that practicing hands-together was more efficient, with one hands-together playthrough of a piece equivalent to practicing the right hand part twice, and then the left hand part twice (rather than equivalent to practicing once with each hand, as you might expect).  This implies that hands-separate practice is inefficient.  However, the subjects in this study were trained musicians, able to learn the pieces to a fully memorized level in two practice sessions.  If the pieces were more difficult to learn, I think that would increase the amount of attention required for playing hands-together.  In that case, the hands-together method might lose some of its advantage.  Also, Rubin-Rabson points out that speed of learning is not the most important goal; clarity and precision of playing are also key, and seem to be improved by practicing hands-separately.

There is one other study that I read that points to an answer to the hands-separately or hands-together question.  It’s a paper authored by Robert Duke and colleagues.  In this study, a number of pianists were given an excerpt to practice, and the researchers looked at what sort of practicing behaviours were used and what led to the best performance.  One of the conclusions was that the best performances came from pianists who played hands-together early on in the practice session.  

As far as I can tell, there aren’t any more recent studies on this issue, and the standard method of learning piano pieces is still the hands-separate method.

Here’s my conclusion from all this morass of information:  I suggest that we encourage students to start playing their pieces with both hands as soon as possible.  If a new piece is difficult, it may be beyond the attentional limits of the student to play it hands-together immediately – this will just lead to frustration.  In that case, the student could play through each hand's individual part (or focus on tricky bits in each hand), and then try again hands-together.  Or perhaps practice just the left hand alone, and then try with both hands.  This approach has the advantage of limiting inhibition between the two sides of the brain, and also stretching the attention capacity of the mind.  The more we try to play hands together, the better we get at paying attention to all those notes at once.  This can only help our hands-together sight-reading abilities.

I think the bottom line is that, although there’s certainly value in hands-separate practicing to focus on details, we don’t really improve at playing hands-together by practicing hands-separately.  This is definitely a different approach than the one I was taught with, and it’s not really what I’ve been doing with my own students.  But I’ve also noticed that my own children are always eager to play their pieces hands-together before they know them well hands-separately, because it’s more satisfying to hear both parts at once.  And we could argue that satisfaction in playing is really what it’s all about.

I'd love to hear your thoughts on this topic.

References

Brown RA. (1933). The relation between two methods of learning piano music. Journal of Experimental Psychology. 16:435-441.

Duke RA, Simmons AL, Cash CD. It’s Not How Much; It’s How: Characteristics of Practice Behavior and Retention of Performance Skills. Journal of Research in Music Education. 2009;56(4):310-321.

Hiraga CY, Garry MI, Carson RG, Summers JJ. (2009) Dual-task interference: attentional and neurophysiological influences. Behav. Brain Res. 205(1):10-18.

Rubin-Rabson G. (1939)  Studies in the psychology of memorizing piano music.  I.  A comparison of the unilateral and the coordinated approaches. Journal of Educational Psychology. 30(5):321-345.

Vercauteren K, Pleysier T, Van Belle L, Swinnen SP, Wenderoth N. (2008). Unimanual muscle activation increases interhemispheric inhibition from the active to the resting hemisphere. Neurosci. Lett. 445(3):209-213.