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Musical roots may lie in human voice
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Lowell Prange
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Aug 14, 2003 18:43 PDT
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I disagree with this but it helped me crystalize some of my own ideas on
the relationship between math and music. I'll post my own remarks later in
a seperate post.
| | http://www.newscientist.com/news/news.jsp?id=ns99994031
13:28 06 August 03
NewScientist.com news service
Key universal features in world music may have their roots in the
ever-present sound of the human voice during the course of evolution,
suggests a new study.
The analysis of thousands of recorded speech samples found peaks in
acoustic energy that precisely mirror the distances between important
notes in the twelve-tone scale, the system that forms the foundation of
almost all music.
"The mysteries of music have a biologically principled explanation," says
Dale Purves, at Duke University, North Carolina, and lead author of the
study. "A reasonable speculation is that we hear these tonal relationships
because they are involved in our interpretation of each other's speech."
As a slide whistle shows, it is possible to change seamlessly the pitch of
a sound from low to high and back again. But for making music, human
cultures have sliced the pitch dimension into twelve distinct tones.
This twelve-tone "chromatic scale" can be heard by starting at any piano
key and then playing the next dozen white and black keys in succession. On
the thirteenth note, the scale begins again, one octave higher.
Pythagoras's theorem
Different musical traditions have characteristic sound because many
cultures have devised scales from a subset of the full chromatic scale,
with different distances, or "intervals," between the tones. Chinese music
is based on five-tone scales, while scales common in Western music have
seven tones.
But all cultures favour certain intervals from the chromatic scale, and
listeners judge these same intervals to create the most harmonious
combinations of two tones. Pythagoras proposed that such preferences could
be predicted from mathematical relationships between tones, but these
approaches have yet to provide a complete explanation.
The Duke researchers randomly extracted over 100,000 speech samples, each
0.1 second long, from recordings of thousands of English sentences.
Acoustic analysis of the combined samples revealed 10 frequency peaks that
match the most significant intervals used in musical scales worldwide.
Mandarin and Farsi
Moreover, the relative heights of the peaks backed numerous studies in
which listeners ranked the harmoniousness of intervals. Speech in other
languages -- Mandarin, Farsi, and Tamil -- also displayed the same
pattern.
The frequency peaks are caused when a sound wave from the vocal cords is
shaped by resonances of the throat and oral cavity. The researchers say
that, aside from animal calls, speech emanating from oscillations of the
human vocal cords is virtually the only natural sound that we hear as
tones.
This fact, combined with the new finding that preferred musical intervals
are better predicted by the acoustic quirks of the human vocal tract than
by mathematics, leads the scientists to argue that the structure of music
is rooted in our long exposure to the human voice over evolutionary time.
Journal reference: Journal of Neuroscience (vol 23, p 7160)
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