Underlying Overtones

The heartbeat theory suffered cardiac arrest, but it was never intended as a serious contender. It was just a prop for illustrating the four hurdles. Speech, on the other hand, is a much more plausible starting point as a foundation for music. But haven’t we already discussed speech? Wasn’t that what the previous chapter was about? We concluded then that speech sounds like solid‑object physical events: the structural regularities found among solid‑object events are reflected in the phonological patterns of human speech. Speech is all about the phonemes, and how closely they mimic nature’s pattern of hits, slides, and ring sounds. Music, on the other hand, cares not a whit for phonemes. Although music can often have words to be sung, music usually gets its identity not from the words, but from the rhythm and tune. Two songs with different words, but with the same rhythm and pitch sequence, are deemed by us to be the same tune, just with different words. That’s why we use the phrase “put words to the music”–because the words (and the phonemes) are not properly part of the meat of the music. The most central auditory feature of speech–its phonological characteristics–is mostly irrelevant to music, making speech an unlikely place to look for the origins of music.

Music is not only missing the phonological core of speech, but it is also missing another fundamental aspect of speech, its most evocative aspect: the meaning, or semantics. If music has its source in speech, and is evocative because of the evocative nature of speech, then why wouldn’t music require words with meaning, whether metaphorical or direct? Yet, as mentioned above, neither phonology nor words is an essential ingredient of music. (Although phonology and words are key ingredients in poetry.)

If music comes from speech, then it doesn’t come from the phonological patterns of speech, or from the semantics of speech. Although these core functions of speech are dead ends for a theory of music, there is another aspect of speech I have purposely glossed over. People overlay the sterile solid‑object event sounds of speech with emotional overtones. We add intonation, a pitchlike property. We vary the emphasis of the words in a sentence, reminiscent of the way rhythm bestows emphasis in music (for instance, the first beat in a measure usually has enhanced emphasis). We vary the timing of the word utterances, akin to the temporal patterns of rhythm in music. And we sometimes modulate the overall loudness of our voices, like a musical crescendo or diminuendo. These prosody‑related emotional overtones turn Stephen Hawking computer‑voice speech into regular human speech. And these emotional overtones can be understood even in foreign speech, where our ears can often recognize the glib, the mournful, the proud, and the angry. We’re just not sure what they are glib, mournful, proud, or angry about .

So it is not quite true that speech sounds are sterile. Rather, it is the phonological solid‑object event sounds that are sterile. The overtones of speech, on the other hand, are dripping with human emotion. Might these overtones underlie music? In an effort to answer, let’s discuss the four questions at the heart of any theory of music, the ones I referred to earlier as “brain,” “emotion,” “dance,” and “structure.”

Do we have a brain for the overtones of speech? An overtone theory of music would like to say that music “works” on our brains because it taps into speech overtone recognition mechanisms. Are we likely to have neural mechanisms for recognizing overtones of speech? Although I am suggesting in this book that we did not evolve to possess speech recognition mechanisms, we primates have been making nonspeech vocalizations (cries, laughs, shrieks, growls, moans, sighs, and so on) for tens of millions of years, and surely we have evolved neural mechanisms to recognize them. Perhaps the overtones of speech come from our ancient nonspeech vocalizations, and they get laid on top of the solid‑object physical event sounds of speech like a whipped cream of evocativeness, a whipped cream our auditory system knows how to taste. An overtone‑based theory of music, then, does have a plausible story to tell about why our brain would be highly efficient at recognizing overtones.

Can overtones potentially explain the evocativeness of music, the second hurdle we had discussed for any theory of music? Of course! Overtones are emotional , used in vocalization to be evocative. If music mimics emotional overtones, then it is easy to grasp how music can be evocative.

Can an overtone theory of music explain dance, the third hurdle I mentioned earlier? One can see how the emotional nonspeech vocalization of other people around us might provoke us into action of some kind–that’s probably why people are vocalizing in the first place. That’s a start. But we would like to know why hearing overtones would not just tend to provoke us to do stuff, but more specifically, make us move in a time‑locked fashion to the emotional vocalizations. I have not been able to fathom any overtone‑related story that could explain this, and the absence of any potential connection to dance is a hurdle that an overtone theory stumbles over.

Finally, can overtones explain the structure of music? Do the overtones of speech possess the patterns of pitch, loudness, and rhythm found in music? There is, at least, enough structure floating around in the prosody of speech that one can imagine it might be rich enough to help explain the structure found in music. But despite the nice confluence between ingredients in the overtones of speech and certain similar ingredients in music, overtones appear to be a very different beast from music. First and foremost, what’s missing in the overtones of speech is a beat , and a rhythm time‑locked to a beat. That’s the one thing the lub‑dub theory of music captured, but it is one of the most glaring shortcomings of overtone‑based approaches, and it ultimately takes overtones of speech out of the running as a basis for a theory of music.

Before leaving speech for more fertile grounds–in fact, the next section is about sex–consider the two hurdles where overtones appeared promising: “brain” and “emotion.” I suggested earlier in this section that overtones could rely on ancient human nonlinguistic vocalizations, but there is another potential foundation for overtones’ evocative nature: the sounds of people moving. Rather than music coming from the overtones of speech, perhaps both music and overtones have their foundation in the more fundamentally meaningful sound patterns of humans’ expressive movements. (And perhaps this is the source of the intersections between music and speech in the brain discerned by Aniruddh D. Patel of the Neurosciences Institute in La Jolla, and other researchers.)