In Western styles of music, from classical to pop, some combinations of notes are generally considered more pleasant than others. To most of our ears, a two-note chord of C and G, for example, sounds much more agreeable than the grating combination of C and F# (which has historically been known as the “devil in music”).
For decades, neuroscientists have pondered whether this preference is somehow hardwired into our brains. A new study from MIT and Brandeis University suggests that the answer is no.
In a study of more than 100 people belonging to a remote Amazonian tribe with little or no exposure to Western music, the researchers found that dissonant chords such as the combination of C and F# were deemed just as likeable as the “consonant” chords that most Western listeners prefer.
“This study suggests that preferences for consonance over dissonance depend on exposure to Western musical culture, and that the preference is not innate,” says assistant professor of neuroscience Josh McDermott, who led the study with Ricardo Godoy, a professor at Brandeis University.
For centuries, some scientists have hypothesized that the brain is wired to respond favorably to consonant chords such as the perfect fifth (so called because one of the notes is five steps of the scale higher than the other). Musicians in societies dating at least as far back as the ancient Greeks noticed that in the fifth and other consonant chords, the ratio of the two notes’ frequencies is usually based on integers—in the case of the fifth, a ratio of 3:2.
Others believe that these preferences are culturally determined, as a result of exposure to music characterized by consonant chords. This debate has been difficult to resolve, in large part because very few people in the world today are not familiar with Western music.
“Most people hear a lot of Western music, and Western music has a lot of consonant chords in it,” McDermott says. “It’s thus been hard to rule out the possibility that we like consonance because that’s what we’re used to, but also hard to provide a definitive test.”
In 2010, Godoy, an anthropologist who has been studying an Amazonian tribe known as the Tsimane for many years, asked McDermott to collaborate on a study of how the Tsimane respond to music. Most of the Tsimane, a farming and foraging society of about 12,000 people, have very limited exposure to Western music.
“They vary a lot in how close they live to towns and urban centers,” Godoy says. “Among the folks who live very far, several days away, they don’t have too much contact with Western music.”
The Tsimane’s own music features both singing and instrumental performance, but usually by only one person at a time.
In two sets of studies, conducted in 2011 and 2015, the researchers asked participants to rate how much they liked dissonant and consonant chords. They also performed experiments to make sure that the participants could tell the difference between dissonant and consonant sounds, and found that they could.
The team performed the same tests with a group of Spanish-speaking Bolivians who live in a small town near the Tsimane and with residents of the Bolivian capital, La Paz. They also tested groups of American musicians and nonmusicians.
“What we found is the preference for consonance over dissonance varies dramatically across those five groups,” McDermott says. “In the Tsimane it’s undetectable, and in the two groups in Bolivia, there’s a statistically significant but small preference. In the American groups it’s quite a bit larger, and it’s bigger in the musicians than in the nonmusicians.”
When asked to rate nonmusical sounds such as laughter and gasps, the Tsimane and the other groups showed similar responses. They also showed the same dislike for a musical quality known as acoustic roughness.
The findings suggest that maybe there’s nothing so perfect about a perfect fifth—it’s just one of the sounds we’re accustomed to.