Music is usually considered as a universal art form. It is found in virtually all human cultures and its use is associated with many different human tasks, from the most sacred to the most profane. Its elusive nature has haunted thinkers for millennia. Aristotle, Plato and Pythagoras, among others, devoted much of their time to trying to understand why we feel such a strong bond to music and where does its power comes from.
Music is also a very interesting crossroad of science and humanities. On one hand, musical language is highly susceptible to formalisation: we can readily dissect some of the elements that compose music, such as rhythm, melody or harmony; we can define notes according to their frequency and create them ‘artificially’; we can compose symphonies using our own computers by simply applying mathematical principles. But on the other hand, despite all this analytical power, the most interesting features of music always seem to remain out of grasp. What makes a melody memorable? Why some people love jazz and others abhor it? Is musical perception hard-wired or is it modifiable? Is it culturally inherited or biologically-determined?
One of the difficulties to study the relative weights of nature and culture in musical perception is the lack of ‘control’ individuals, as virtually everyone is exposed to music from an early age. In addition, comparing individuals from different musical cultures has also become increasingly challenging, as Western music has experienced a great expansion in the last decades, leaving few places in the world pristine.
One of these places is Santa María, a remote village in the Amazon rainforest that can only be accessed by canoe and that lacks, among other commodities, electricity and tap water. The people that live there, known as the Tsimane’, are relatively isolated. They hunt, the fish, they farm and sometimes they sing and play music that has an interesting feature: it lacks harmony.
What is harmony?
Harmony is what makes instruments out of tune stand out and sound so terrible. It is also what allows the members of a band or an orchestra to play together. And within a song, harmony is what makes some parts to feel ‘stable’, while others sound tenser and call for a resolution towards stability.
There are some mathematical principles that can partly explain why certain musical interactions sound better than others. They are based on the fact that music, like every other sound, is composed of waves. They way different waves interact determines if the resulting sound is perceived as “consonant” or “dissonant”. This can be easily explained using the example of two guitars with the same type of strings and tuning:
If the two guitarists play the same string on their guitars, the waves from the two notes are equal and they interact perfectly. If now one of the guitarists presses a fret so that the length of the string is halved, the frequency of the vibration will be doubled. This means that for every time the open string vibrates, the fretted string will vibrate twice. Since the interaction has a certain periodicity, we perceive the combination of the notes as consonant and pleasant. But if instead of halving the string the guitarist presses a fret that shortens its length to, let’s say, 16/15 the original length, the interaction with the open string will be much less periodical, as now for every fifteen times the open string vibrates, the fretted string will vibrate sixteen times and we perceive this interaction as dissonant and unpleasant. As a rule of thumb, notes whose frequencies are in simple integer ratios to one another (such as 1/2, 2/3 or 3/4) are consonant, whereas higher integers are considered dissonant.
This theory of consonance is highly appealing, as it matches objective concepts of physics with subjective perceptions of pleasantness. However, we know that it is not always accurate. Blues, for example, should sound terribly dissonant according to the above-mentioned rules. Since blues has been around for more than a century, a possible explanation is that we have grown so accustomed to its dissonances that we no longer perceive them as such.
But the question remains: do we like certain note interactions because biologically we are able to detect their physical consonance or because we’ve inherited a cultural tradition that usually associates pleasantness and consonance?
And here is where the Tsimane’ come on the scene.
Are the harmonic principles universal?
The music from the Tsimane’ is monophonic. This means that their songs consist only of a tune, played or sang by a musician without any other accompaniment. It also means that they don’t use harmony, which makes them ideal to try to answer the question of whether harmony is determined by biology or by tradition.
Researcher Josh McDermott and his collaborators1 travelled to Santa María to see how the Tsimane’ perceive musical consonance, and compared them to other four human groups with different levels of exposure to Western music: residents in the US with or without experience playing an instrument, residents in La Paz and residents in the rural town of San Borja.
The Tsimane’ were the only group to find equally pleasant consonant and dissonant chords, either when played using an instrument similar to a piano or when listened using a recording from a trained singer. This was not due to a difference in what the Tsimane’ consider “pleasant” or “unpleasant”, as, similar to all other groups, they were able to classify laughs as pleasant and gasps as unpleasant.
The results argue in favour of a cultural, rather than biological, association of pleasantness and consonance. This view is also supported by the fact that, the higher the exposure to Western music, the more accurately the subjects rated consonant chords as pleasant.
Far from settling the subject, the finding leads to new questions: how do harmonic preferences emerge when multiple sounds begin to be used by a culture? Is there any human group that uses harmony but lacks a preference for consonant sounds?
Unfortunately, answering these questions will become increasingly difficult. Because, ironically, while globalisation gives us the possibility to listen to music from all over the world with just one click, it also allows the relentless expansion of Western music to even the most remote corners of the planet. As musicologist David Huron puts it, “as globalisation spreads we are running out of time for the quest to encounter the range of possible musical minds”. Let’s just hope we can learn a lot more before time runs out.