Every human culture, without exception as far as anyone can tell, produces some form of music. And yet it seems as though the music that human cultures produce could hardly be more varied: From Italian opera to Croatian klapa to Tuvan throat singing, the assortment of rhythms, melodies, dynamics, and harmonies found in cultures large and small around the world stands as a testament to human creative diversity.
Like language, music is universal among humans and nonexistent – or at least unintelligible to us – in even our closest nonhuman relatives. But music, unlike language, has no obvious adaptive function, prompting scientists who study music to wonder what forces originally gave rise to it. Is music an evolutionary adaptation, or is it purely a human invention?
It’s an old question, one that Charles Darwin took up in his 1871 book “The Descent of Man,” in which he suggested music might have evolved to help our species’ forebears woo potential mates. Others have argued that music evolved from coordinated territorial defense vocalizations, such as those observed in other social animals, including chimpanzees.
But many scholars, particularly ethnomusicologists, have been wary of this so-called adaptationist approach, which was heavy on thought-provoking explanations but light on hard evidence that links music with reproductive fitness. Musicality, according to one prevailing argument, is not a trait, but a technology, a happy result of pre-existing adaptations that, beautiful and uplifting as it may be, confers no evolutionary advantage.
One approach to resolving the debate has been to search for universals in music, commonalities in the pitch, melody, rhythm, harmony, timbre, texture, in the music of societies with no contact with each other. If music is, as Henry Wadsworth Longfellow said “the universal language of mankind,” the reasoning goes, then humanity’s penchant for music may arise from a biological substrate.
“Any study that’s looking at comparisons of lots and lots of cultures, by its nature, is telling us something about human nature,” says cognitive scientist Sam Mehr, director of the Music Lab at Harvard University’s psychology department. “It’s telling us something about how all humans are alike in some way.”
Psychologists have long argued that human language contains such universals. Beginning in the 1920s, the German-American Gestalt psychologist Wolfgang Köhler conducted experiments in which he showed participants images of two shapes, one jagged and spiky and the other bulbous and rounded. When asked to label the shapes with the nonsense words “takete” and “baluba,” participants overwhelmingly associated the spiky shape with “takete” and the rounded shape with “baluba.” This effect has been shown to work in children as young as two and a half years old.
And perhaps a similar effect exists for music. In a paper co-authored with Harvard evolutionary biologist Manvir Singh and published last Thursday in the journal Current Biology, Dr. Mehr and his colleagues gathered samples of vocal recordings from 86 small-scale societies, from the Highland Scots of the Outer Hebrides to the Chuukese of Pulap, Micronesia, to the Nanai of Russia’s far east. The team played 14-second excerpts to 750 internet users in 60 countries, and they found that listeners could correctly identify whether a sample was from a dance song, a lullaby, a love song, or a healing song.
“It doesn’t seem to matter where the listeners are,” says Mehr. “They all seem to agree with each other quite quite strongly. There’s a very high consistency.”
But why would songs from radically different cultures trigger the same feelings in diverse listeners?
“There are some words that sound like the thing they represent,” says American-Canadian cognitive neuroscientist, musician, and record producer Daniel Levitin, author of two popular science books on music – “This Is Your Brain on Music“ and “The World in Six Songs.” “And there are some aspects of music that sound like the thing they represent. Very slow music sounds more like somebody’s walking slowly.... And fast music sounds more like someone running or celebrating,” he says. “These kinds of mappings have crept their way into this wonderfully diverse collection of different music.”
Mehr, who says that this experiment is just the first of several in his multidisciplinary Natural History of Song project, is particularly interested in researching lullabies. These songs are thought to exist in every culture but have been historically ignored by researchers, who have tended to focus on music associated with courtship or public celebration.
“If there is music happening by women, and it’s usually the case that there is, you often don’t see it, or it doesn’t get reported,” says Sandra Trehub, a psychologist at the University of Toronto Mississauga who specializes in how infants respond to music. “It tends not to be the music of that culture that celebrated or considered important.”
As any parent of young children knows, efficiently getting one’s kids to sleep can free up resources that can be used for completing chores, sleeping, or even producing more children.
“In the western world, we take pride for some reason in having babies who can soothe themselves,” says Dr. Trehub. “But elsewhere, singing babies to sleep is the name of the game, and it works. I’ve seen it work like magic everywhere.”
Of course, lullabies are likely only part of the picture. “Music didn’t evolve for a single reason but for several reasons. I think that new study supports that notion,” says Dr. Levitin. “I don’t know of a primate group where more than 18 males can live together before rivalries and jealousies tear them apart. And yet humans have been living in cities of hundreds of thousands of people for thousands of years. So we came up with some way to get along and communicate our desire to get along.”