MUSIC is not tangible. You can’t eat it, drink it
or mate with it. It doesn’t protect against the rain, wind or cold. It doesn’t
vanquish predators or mend broken bones. And yet humans have always prized
music — or well beyond prized, loved it.
In the modern age we spend
great sums of money to attend concerts, download music files, play instruments
and listen to our favorite artists whether we’re in a subway or salon. But even
in Paleolithic times, people invested significant time and effort to create
music, as the
discovery of
flutes carved from animal bones would suggest.
So why does this thingless
“thing” — at its core, a mere sequence of sounds — hold such potentially
enormous intrinsic value?
The quick and easy
explanation is that music brings a unique pleasure to humans. Of course, that
still leaves the question of why. But for that, neuroscience is starting to
provide some answers.
More than a decade ago, our
research team used brain imaging to
show that music that
people described as highly emotional engaged the reward system deep in their
brains — activating subcortical nuclei known to be important in reward,
motivation and emotion.
Subsequently
we found that listening to what might be called “peak emotional moments” in
music — that moment when you feel a “chill” of pleasure to a musical passage —
causes the release of the neurotransmitter
dopamine,
an essential signaling molecule in the brain.
When pleasurable music is
heard, dopamine is released in the striatum — an ancient part of the brain
found in other vertebrates as well — which is known to respond to naturally
rewarding stimuli like food and sex and which is artificially targeted by drugs
like cocaine and amphetamine.
But what may be most
interesting here is when this neurotransmitter is released: not only
when the music rises to a peak emotional moment, but also several seconds
before, during what we might call the anticipation phase.
The idea that reward is
partly related to anticipation (or the prediction of a desired outcome) has a
long history in neuroscience. Making good predictions about the outcome of
one’s actions would seem to be essential in the context of survival, after all.
And dopamine neurons, both in humans and other animals, play a role in
recording which of our predictions turn out to be correct.
To dig deeper into how music
engages the brain’s reward system, we designed a
study
to mimic online music purchasing. Our goal was to determine what goes on in the
brain when someone hears a new piece of music and decides he likes it enough to
buy it.
We used music-recommendation
programs to customize the selections to our listeners’ preferences, which
turned out to be indie and electronic music, matching Montreal’s hip music
scene. And we found that neural activity within the striatum — the
reward-related structure — was directly proportional to the amount of money
people were willing to spend.
But more interesting still
was the cross talk between this structure and the auditory cortex, which also
increased for songs that were ultimately purchased compared with those that
were not.
Why the auditory cortex?
Some 50 years ago, Wilder Penfield, the famed neurosurgeon and the
founder of the Montreal
Neurological Institute, reported that when neurosurgical patients received
electrical stimulation to the auditory cortex while they were awake, they would
sometimes report hearing music. Dr. Penfield’s observations, along with those
of many others, suggest that musical information is likely to be represented in
these brain regions.
The auditory cortex is also
active when we imagine a tune: think of the first four notes of Beethoven’s
Fifth Symphony — your cortex is abuzz! This ability allows us not only to
experience music even when it’s physically absent, but also to invent new
compositions and to reimagine how a piece might sound with a different tempo or
instrumentation.
We also know that these
areas of the brain encode the abstract relationships between sounds — for
instance, the particular sound pattern that makes a major chord major,
regardless of the key or instrument. Other studies show distinctive neural
responses from similar regions when there is an unexpected break in a
repetitive pattern of sounds, or in a chord progression. This is akin to what
happens if you hear someone play a wrong note — easily noticeable even in an
unfamiliar piece of music.
These cortical circuits
allow us to make predictions about coming events on the basis of past events.
They are thought to accumulate musical information over our lifetime, creating
templates of the statistical regularities that are present in the music of our
culture and enabling us to understand the music we hear in relation to our
stored mental representations of the music we’ve heard.
So each act of listening to
music may be thought of as both recapitulating the past and predicting the
future. When we listen to music, these brain networks actively create
expectations based on our stored knowledge.
Composers and performers
intuitively understand this: they manipulate these prediction mechanisms to
give us what we want — or to surprise us, perhaps even with something better.
In the cross talk between
our cortical systems, which analyze patterns and yield expectations, and our
ancient reward and motivational systems, may lie the answer to the question:
does a particular piece of music move us?
When that answer is yes,
there is little — in those moments of listening, at least — that we value more.
