Audio illusion: the accelerating metronome

Here’s an experience I had a few years ago while practising to play in Smetana’s Bartered Bride overture. As I remember, I was playing in the second violins at the time.

The music

The main feature of the overture’s opening is that each violin section has to play a long, continuous stream of very fast semiquavers for the first page or so. (Probably this applies to the other string sections too.) Since  players of other parts have to fit their semiquavers to them when they join in, the music can hold together only if they’re played accurately in time. Accuracy is essential.

This is a dangerous situation: the natural tendency of a stream of equal notes is to rush, and they’ll rush even more if the player is feeling a bit panicky about playing them. In an amateur orchestra it’s likely that at least some players will be tempted to experience such panic. And once any rushing starts, it won’t be unaimous: everyone will accelerate differently so they’re no longer playing the same notes at the same time.

This kind of rushing is contagious, too. So all a passage like this really needs in order to risk disaster is for one player to start rushing and a few others nearby to lose their nerve. It’s a very short step from that to total chaos.

The practice

So this was one of those rare cases where it was a good idea to practise with a metronome. (Normally this is a bad idea; it leads to a mechanically rigid tempo, which in most circumstances is unmusical.) There were two main aspects I had to practise: (i) learning the notes and fingerings well enough not to stumble over anything; (ii) keeping the tempo absolutely constant.

So I practised with a metronome, considerably below tempo at first, and increasing the speed very gradually. (The aim in this sort of practice is to repeat the experience of getting the notes right until you can do so at full tempo—not to repeat the experience of getting them wrong and of being forced to play too fast. Otherwise you’re training yourself to get them wrong, not to get them right.) Eventually I could play the entire passage, up to speed (with a little extra left over for comfort) and in time.

Practising like this involves quite intense concentration on very short timescales: listening to hear whether each note is coming out correctly, paying attention to the feeling in the fingers as they either automatically go to the correct note or try to play the wrong one, keeping the bow stroke metronomic, watching out for any hint of stumbling, and so on.

The illusion

But what was really interesting about these practice sessions was what happened once I stopped playing. Within a few seconds, I had the impression that I could hear the metronome speeding up. In fact it seemed to be accelerating quite dramatically. So much so that if it had been a fellow player in the orchestra I’d have thought they were rushing quite badly. I estimate that the apparent increase in speed was around 15%–20%.

But of course the metronome wasn’t suddenly speeding up; it’s a highly accurate electronic one, and all that had happened was that I’d stopped playing notes on the violin. Yet it was almost impossible to believe that the metronome wasn’t accelerating. I could hear it going faster and faster.

I interpreted this as my perception slowing down, now that I was no longer concerned with what happened from one tenth of a second to the next. It seemed as though my mind had sped up in order to play the fast music, and was now returning to its normal pace.

I wonder whether this is one of the reasons musicians have to train themselves not to rush when playing fast music. If your time perception changes so the music feels much slower than it actually is, you’ll have no idea that you’ve sped up. It’ll feel as though you’re playing at just the same speed you were all along. As musicians we have to learn what kinds of passages are prone to rushing, and how it feels not to rush. Often this involves playing at a speed which feels as though it’s definitely too slow, or making a conscious effort to slow down—while in fact playing at exactly the same speed.

I was reminded of all this today when a friend tweeted a link to this article about an experiment on mindfulness meditation. This form of meditation emphasises awareness of the present moment. The research found that the meditation made time appear to pass more slowly for the participants, in a way that sounds very similar to what happened while I was practising. And maybe for similar reasons: focusing on the current moment as a meditation exercise, and focusing on the current note being played as a practice exercise, seem to me to involve exactly the same focus of attention, even if the mental state involved isn’t identical.

In any case it was fascinating to be able to witness my own sense of the passage of time changing over the course of a minute or so as I came out of intense practice mode.

One response to “Audio illusion: the accelerating metronome

  1. Tim,
    What an interesting reflection on an illusion that I am quite familiar with. Perhaps it’s why I often avoid metronome. It can so easily play with my mind.

    You mention that you “wonder whether this is one of the reasons musicians have to train themselves not to rush when playing fast music” in regards to this illusion. I definitely think it it one of the reasons. One thing that I would add is that instead of looking at the solution as “I need to learn not to rush” I strive to say instead, “I want to get into the piece’s groove and to love the feeling of that groove so much that rushing will feel wrong.” It’s a small difference but prevents me from slipping into my growing up years when my teacher and mother regularly shouted at me, “Stop rushing!” That phrase haunts me to this day, causes tension, and usually causes me to rush.

    Thank you for this thought-provoking post, Tim!

    Erica

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s