Sunday, February 07, 2010

Science Sunday: Your Brain On Music

It is a testament to the complexity of the brain that despite decades of research we still have relatively little understanding of why so many of us enjoy music so deeply and revel in its ability to alter our moods, trigger memories and even change our lives.

That is just fine with me as someone who has never heard a kind of music that he didn't like. (Okay, I admit that I can get by on about a half hour of polkas a year.)

Music is pretty much my full-time companion. It wakes me up in the morning and relaxes me in the evening. It helps me celebrate good times and weather bad times. It makes me move my body in fun and interesting ways when the Dear Friend & Conscience and I are at a concert or roll up the living room rug on a Saturday night and boogie. And I can say without equivocation that it does strange and wondrous things to my mind.

Yet for all of the music that I have absorbed since I first heard "Pop Goes the Weasel" played on a jack in the box, I don't have a clue as to how and why it does those things to my mind.

But now scientists are finding the first promising clues, among them that the act of listening is really an act of neural prediction.

This discovery was based on a computational model used in an experiment. The model, as Johan Lehrer so ably explains, demonstrated that statistical predictions based on our personal listening experience -- "because I listen to Bruce Springsteen, I'm able to predict the melodies of John Mellencamp," as he put it -- was much better at simulating the mind than a rule-based model, in which our expectations are fixed and inflexible.

It took me about thislong to understand what the model proved, and serendipitously so because just the other evening I was webstreaming a jazz radio station and remarked to the DF&C that as I slide into my dotage my understanding of jazz composition and the relationship between the sub-genres in jazz -- say bop to bebop to hard bop -- has become pretty deep. In other words, my affection for bebop has opened wide my ears (which is to say my mind) for its brother sub-genres in ways it once was incapable of doing.

The scientists conducting the experiment measured the brain waves of 20 subjects while they listened to various hymns and found that unexpected notes -- pitches that violated the previous melodic pattern -- triggered an interesting sequence of neural events and a spike in brain activity.

As Lehrer further explains, it is apparent that music "hijacks" some very fundamental neural mechanisms:

"The brain is designed to learn by association: if this, then that. Music works by subtly toying with our expected associations, enticing us to make predictions about what note will come next, and then confronting us with our prediction errors. In other words, every melody manipulates the same essential mechanisms we use to make sense of reality."

Music also requires surprise such as the dissonance of what Lehrer terms "low-probability notes":

"While most people think about music in terms of aesthetic beauty -- we like pretty consonant pitches arranged in pretty patterns -- that's exactly backwards. The point of the prettiness is to set up the surprise, to frame the deviance. (That's why the unexpected pitches triggered the most brain activity, synchronizing the activity of brain regions involved in motor movement and emotion.)"

All of this highlights, at least for me, why some music and musical instruments provoke such an emotional response.

Music with passages in minor keys can do that, while certain organ, accordion and violin playing (yes, in minor keys but not necessary so) can bring tears to my eyes.

IMAGES OF MUSIC (From top): By Lena Emmertz, Stephanie Cox, Ann Kavanagh, Marilyn Banner, Yuko Adachi and George Pali.

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