A pair of studies by Duke University neuroscientists shows powerful new evidence of a deep biological link between human music and speech.

The two new studies found that the musical scales most commonly used over the centuries are those that come closest to mimicking the physics of the human voice, and that we understand emotions expressed through music because the music mimics the way emotions are expressed in speech.

In a paper appearing in the Journal of the Acoustical Society of America (JASA), the Duke team, led by Dale Purves, a professor of neurobiology, found that sad or happy speech can be categorized in major and minor intervals, just as music can. So your mother was right: It's not only the words you say, but how you say them.

In a second paper appearing Dec. 3 in the online journal PLOS One, Kamraan Gill, another member of the team, found the most commonly used musical scales are also based on the physics of the vocal tones humans produce.

"There is a strong biological basis to the aesthetics of sound," Purves said. "Humans prefer tone combinations that are similar to those found in speech."

This evidence suggests the main biological reason we appreciate music is because it mimics speech, which has been critical to our evolutionary success, said Purves, who is also director of Duke's Neuroscience and Behavioral Disorders Program and executive director of the A*STaR Neuroscience Research Partnership at the Duke-NUS Graduate Medical School in Singapore.

To study the emotional content of music, the Duke team collected a database of major and minor melodies from about 1,000 classical music compositions and more that 6,000 folk songs and then analyzed their tonal qualities.

They also had 10 people speak a series of single words with 10 different vowel sounds in either excited or subdued voices, as well as short monologues.

Source: Duke University