Music is made by combining notes.
And one of the hallmarks of Western music
is that there are certain combinations of notes
that people typically consider to be
pleasant and certain combinations of notes
that people consider to be unpleasant.
And this is true to some extent in other musics as well,
but it's a very important phenomenon in Western music.
And so going back thousands of years,
people have wondered why it is that some combinations sound
good to people and other combinations don't.
So scientists have often hypothesized
that the preference for consonance over dissonance
has a biological basis and that people might be born with it.
Ethnomusicologists and composers in contrast
have typically assumed that consonance
is a cultural invention that would
be unique to Western listeners who grow up in Western culture.
And one of the reasons why this question has remained
unresolved is because there's remarkably little
experimental data in individuals that
don't have massive amounts of exposure
to Western culture and Western music.
So to try to answer this question,
we went to a rural part of Bolivia
and did some experiments on a society called the Chimane.
They're an indigenous society in the Bolivian Amazon rainforest,
and they're pretty out of the way.
The Chimane live in these villages that
are scattered around the Amazon basin,
and the ones that are most remote
are really hard to get to and pretty far removed
from developed Western culture.
So in order to do experiments on them,
we brought laptops and headphones
and a gasoline generator down to Bolivia
and took them with us to these Chimane villages.
And the experiments were very simple.
We would play them sounds and just
ask them to tell us whether they like them or disliked them.
[TWO SIMILAR BUT DIFFERENT SOUNDS]
So we would play them either consonant combinations of notes
or dissonant combinations of notes.
And what we found when we analyzed
the data was that in contrast to Westerners
who will very consistently tell you that the consonant
combinations are pleasant-- they like them--
and that the dissonant combinations are
unpleasant-- they don't like them--
the Chimane rated them as equally pleasant.
So this was a pretty striking difference
from Western culture.
Of course, there's lots of explanations
for why they would give you equal ratings for two things,
perhaps they didn't understand the task or something
And so we did a bunch of control experiments.
And so in contrast what happens with consonant and dissonant
chords, when you ask them to rate recordings of people
either laughing or gasping in fear,
you find that they respond very similarly to Westerners.
So both Westerners and Chimane listeners
will tell you that laughter is pleasant
and that gasps are unpleasant.
And so that gave us some confidence
that they actually understand the task
and that the lack of a difference between consonance
and dissonance was not due to some uninteresting factor.
So the significance of these results, I think,
is that they suggest that the preference for consonance
is not something that we are simply born with,
and they're not something that develops
as a consequence of just any kind of exposure
to natural sounds or to any kind of music.
They require exposure to a particular kind of music,
namely those it feature harmony, we think.
And that's really what we think differentiates the Chimane
and these other groups in Bolivia
from American listeners.