From a neurological and evolutionary perspective, music is fascinating. There seems to be a deeply rooted biological appreciation for tonality, rhythm, and melody. Not only can people find certain sequences of sounds to be pleasurable, they can powerfully evoke emotions. Music can be happy, sad, peaceful, foreboding, energetic or comical. Why is this? Music is also deeply cultural, with different cultures independently developing forms of music that are very different from each other. All human cultures have music, so the question is – to what extent are the details of musical appreciation universal vs culturally specific?

In Western music, for example, there are minor and major scales, chords, and keys. This refers to the combinations of notes or intervals between them. Music in a minor key tends to evoke emotions of sadness or foreboding, while those in a major key tend to evoke happiness or brightness. Would anyone from any culture interpret major and minor key music the same way? Research suggests that major and minor emotional effects are universal, but a recent study casts a little doubt on this conclusion.

The researchers looked at different subpopulations of people in Papua New Guinea, and both musicians and non-musicians in Australia. They chose Papua New Guinea because the people there share a common musical tradition, but vary in their exposure to Western music and culture. The experiment was simple – subjects were exposed to major and minor music and were asked to indicate if it made them feel happy or sad (the so-called emotional “valence”). Every group had the same emotional valence in response to major and  minor music – that is, except one. The one group that had essentially no exposure to Western culture and music did not have the same emotional reaction to music.

The authors conclude from this that, at leas to some extent, the emotional valence of different kinds of music is a culturally learned language. They also point out, however, that this one study does not rule out that musical appreciation is universal. But it does call that conclusion into question, at least to some extent. How does this fit into our current theories about the evolution of music?

That is really the deeper and more interesting question here – why does music exist at all? Why did such a deep and extensive appreciation for music, with clear emotional effects, evolve? Was it purely an epiphenomenon or was there some evolutionary advantage? Also, how does the evolution of music relate to the evolution of language?

From a neuroscience point of view (a good place to start), music and language are distinct but connected. Language processing for words, meaning, and grammar are located in the dominant hemisphere (by definition), which for most people is the left hemisphere. Musical appreciation resides in the mirror structures in the non-dominant (usually right) hemisphere. This includes the prosody of speech – the ability to interpret the inflections and tones of speech in order to infer emotion and meaning. How do you know when someone is being sarcastic? Largely because of the prosody of speech. For those with a stroke or lesion in this part of the brain, they have a difficult time inferring people’s meaning because they lack an entire dimension of language communication.

This neuroscience is perhaps an important clue as to the evolution of music. Perhaps it is part of the evolution of language, which includes prosody. But we also have to ask (and not just assume) – did music evolve out of language, or did language evolve out of music? While clearly they evolved together, there is good reason to think that music evolutionarily predated language. Our ancestors, partly as evidence by extant primates, likely communicated with howls and hoots, to augment gestures and facial expression, even before they had anything resembling words or language. Being able to read the emotion of a tribe member was critical to survival. Were they excited because they just found a tree full of fruit, or because they just spotted a predator hunting them? And so emotions became tightly encoding in tone and pitch. It is likely that only later were words added to enhance this communication.

It is also likely that the first musical instrument was the human voice. Singing is both music and language, and is essentially an enhanced form of communication where the prosody is emphasized and intensified. Singing and music likely became an important mechanism of group cohesion, of shared culture, and part of a shared language and story. This perhaps is similar to poetry, which is a creatively enhanced version of speech.

Music, of course, incorporates other elements, such as rhythm, which neurologically relates to our cerebellar function, the ability to discern timing and pacing. Music can also “hack in” to this programming in the brain, feeding our penchant for regular timing and pattern recognition, while also hacking into the connection between prosody and emotion.

But of course music is also cultural, just as language is both hard-wired and cultural. The ability to have language, and certain elements of grammar, appear to be universal, but the specific manifestation of language is cultural and can vary tremendously. Music is its own type of shared cultural language, but based in universal predispositions and neurological functioning. Composers and their audiences have learned this shared language over the years, reinforcing emotional reactions and understanding what music is supposed to convey. We know when something scary is going to happen in a horror movie, because the music tells us.

Music is a complex interplay of being both cultural and universal, in the same way language is. Music is also closely tied to communication, and in fact may have predated language itself. In this context it makes sense that it can be so emotionally powerful.