Friday, July 12, 2013

Music and synchronized heartbeats

I once heard the otherworldly baroque cellist Anner Bylsma in concert.  It was many years ago, but I remember that he played some of the Bach cello suites, some of the most challenging and beautiful pieces of music that a cellist can play.  He commented with bemusement that he found it ironic that soloists were expected to sound like many musicians at once, while the many musicians in an orchestra section are expected to sound as one.

Here he is playing Suite no 1. It is simply majestic.  I know people who want to hear Bach as they lay dying, and this is why. 

Now comes a paper saying that musicians together may do more than sound as one.  Their hearts may beat as one.  Or rather, synchronize.  This is choir members, who apparently control their breathing enough that it affects their heart beat, and when they are singing in unison their hearts accelerate and decelerate together.  The authors of this paper discuss the implications of this for the health and well-being of the singers, but I prefer to think of it less prosaically.

Dictyostelium discoideum, slime mold, are amoeba that live in the soil. Their life cycles are interesting; at some stages they are single celled organisms going it alone, but when conditions are right (or wrong -- when the individuals sense that nutrients are being depleted, generally because there are too many amoeba consuming them), the individuals mass together, eventually becoming a fruiting body that releases spores and starts the cycle again. 

Dicty life cycle; Wikimedia Commons

Each aggregate may be comprised of multiple species.  Once they've come together, some cells will undergo apoptosis (that is, programmed cell death -- kill themselves) for the good of the group, even when it includes cells they aren't as close kin to as others.

But this phenomenon is not just a strange evolutionary quirk of slime mold.  Most if not all bacteria can do this.  They have what's called "quorum sensing" which allows them to detect the population density around them.  They respond to high population density in numerous ways, but one common response is to group together into a biofilm, a group of often diverse bacterial species that has a modicum of structure, and can do things that each cell cannot do alone, such as better resist antibiotics.  They have been doing this since before there were multicellular organisms as we know them.

Hive insects, ants, termites, wasps, bees, and so on, are similar.  Individual insects each contributing to the good of the hive, and each surviving only because of the hive.  Enough so that hives are often considered to be superorganisms.  This behavior probably evolved before vertebrates like us did.

Maybe choirs are superorganisms too.  As singers aggregate into groups, specializing as bass, alto, tenor, soprano, they can reach ethereal heights that those of us who sing in the shower cannot.  Perhaps it is good for the singers' health, but I think more, it is good for our souls. 


James Goetz said...

I appreciate reading this because I recently worked on a theory of organization that is in review. Here is an interesting chapter on self-organization and collective behavior among vertebrates including schools of fish, herds of mammals, primate communities, and human crowds (,%202003.pdf). It also includes references to symbiosis and colonial organization. Now I appreciate seeing this fascinating research of choirs.

Ken Weiss said...

Thanks for your comment (as usual)!

We've just heard a recent BBC program on related subjects and will be doing a post on that, probably next week.