By Richard Black
BBC science correspondent, August 6, 2003
Scientists in the United States believe they have solved one of the oldest puzzles in psychology - why does music take the form it does?
Writing in the Journal of Neuroscience, they say musical structure - chords and scales - is connected with patterns found in human speech.
The chord is the traditional building block of music from Haydn to Hendrix.
Chords and melodies can be broken down into their smallest parts, producing a scale of 12 notes - the chromatic scale.
It is not just a western phenomenon. Many musical traditions - some experts would say most - use the same 12-note scale.
"You have many musical cultures that don't have a 12-note scale, they may have five notes, a pentatonic scale, and yet we could not find any that had notes that were not in the chromatic scale or very close to it," David Schwartz of the Duke University in North Carolina told BBC News Online.
He said: "Not all these other cultures had all the notes we have, but there didn't seem to be any that have notes that we don't have."
But the researchers wondered why music was divided into 12 notes - why not 14, or 20, or three?
According to Dr Schwartz and his colleagues, it is because we are trained to by the sounds of speech.
The human speaking voice produces certain combinations of frequencies - pitches - and we look for those same combinations in music.
He said: "Speech is special because it is the sound that we are most often exposed to...
"We are immersed in it, we are bathed in it, we live in an acoustic environment dominated by speech and therefore speech sounds are going to play a major role in shaping the evolution and development of the auditory system."
One of the most pleasing musical chords is known as a major third and we find it familiar and pleasant, according to the new theory, because sub-consciously we hear the same combination daily in speech.
He said: "The reason why our perception seems to correspond so nicely with the statistical structure of speech sounds is that the brain... has in some way internalised the statistical structure of the sound environment we inhabit...
"There is this nice match between mind and world," said Dr Schwartz. http://news.bbc.co.uk/1/hi/sci/tech/3129145.stm