How your brain turns frequencies into music

How is music actually created? The most likely response is to answer that it comes from an instrument. Or several. But in fact music is first created in our brains.

When the air carries sound waves to your ear, they mill through your auditory canals at around 1000 km/h and finally collide with your eardrum at the end of the cul-de-sac, this impact sets off a fabulous chain reaction on the other side of your eardrum. In the end, you hear a sound (our vocal coach Lea Lu even sees colors in the process, she's a so-called synesthesiologist). If you look at a sheet of music, there are notes that are the alphabet for tones. Play the notes in the given order, and out comes a piece of music. So tones would have to be music, right? While this assertion isn't wrong at all, it's also not entirely complete. What has to happen for tones to become music has to do with physics, mathematics, biochemistry, neurology and on top of that, a good dash of psychology.

TL;DR: Music as an emotional experience is more than tones strung together. It is not created on the music sheet, but first in your head, as your brain tries to find patterns in the tsunami of frequencies and rhythms.

Let's go back to the moment when sound just arrived in your eardrum. Just before, you pressed a key on the piano, bowed the string of your violin, hit a tom of your drum set - whatever. Now begins the physical part of hearing, because that movement in turn caused air to vibrate, and that vibration was carried to your pinna and through the coils of your ear canal to your eardrum, a thin membrane.

This is where the anatomical part of hearing begins: the eardrum passes the vibration on to the tiniest bones of your skeleton, which are connected to a curled-up tube in which the finest hairs are surrounded by a viscous fluid. As soon as the fluid begins to move, certain hairs are bent.

At this point, the neurological part of hearing begins: if a hairs is bent hard enough, an electrical voltage is discharged at its root, which shoots up into the brain and is picked up by the auditory center. There, the impulse is passed from cell to cell until it is the turn of the one responsible for that very signal. At that moment, our consciousness flares and we register the sound.

The sound wave that forms the origin of the sound in your head can be mapped as a so-called sine wave and has a frequency. Frequencies are expressed in hertz (Hz), and the tones that shoot through space and time as sinusoids are called sinoidal tones. Sinodial tones have a fundamental frequency and overtones that are multiples of the fundamental frequency. Certain hairs respond to certain frequencies, and knowing this helps to understand what harmonics are - the next mystery about music.

To get a harmony, one tone alone is not enough. It takes several of them, and they must first have the right frequencies. The tones in combination sound consonant (another word for "harmonic") in your ear, if the their respective frequencies are in a favorable relationship to each other. Multiple tones with the same fundamental frequency or divided harmonics sound pleasant, harmonic even.

An excellent example to understand this thing about frequencies and harmony is tuning a guitar: as you turn the action and screw the note higher or lower, you can easily hear how the waveforms of the two tones slowly nestle together or begin to tangle. Where the vibration of the strings creates a pattern within the same frequency range, there is harmony, otherwise there is not. Harmony, then, is a bone-dry mathematical matter.

Now imagine you've struck a heartwarming triad. The harmony couldn't be sweeter, a comforting shiver runs down your spine and goosebumps creep down to your palms. And yet: After a few seconds the intoxication is through, and with every time you let your killer triad sound, the pleasant feeling lasts less long. Until the end you go bored to the cleaning closet and start sorting light bulbs.

What you're still missing is a story, a theme with an arc of suspense, lots of little subplots, a twist or two and finally a successful resolution. In other words, you're missing the melody. While tones are a physical, anatomical and neurological phenomenon, and harmonies follow mathematical laws, melody is where psychology kicks in. It's the rhythmic sequence of frequencies that turns harmony into a story. We humans may like sunbathing, greasy food and comfortable places to sleep - but we LOVE stories. Our brains are crazy about stories because they put everything in a logical sequence and provide order (spoiler alert: This is also the hinge between sounds and music). However, they are quite demanding when it comes to stories - if the plot is too easy to see through, too simple, we get bored abruptly. And if it's too twisted and convoluted, too complicated, we dismiss it outright as noise.

Critical readers will rightly ask themselves here: who or what decides that the tune is too simple or too detached? The answer is: it is our individual associations, the inner images and moods that are triggered by the harmonies and their progression. It's a question of personal taste, but also of the social environment, from which we have copied a certain aesthetic sensibility while growing up. And with this template for what is beautiful and exciting in life, we now approach this melody with a certain expectation; we imagine what will happen next. The fact that we do not simply let the melody sprinkle us and have completely switched off the head, has to do with our brain and its literally neurotic relationship to patterns. The brain is a specialist in recognizing patterns. This is necessary so that we can move quickly through everyday life, without having to deal with every detail for an eternity: Being able to recognize regularities in our environment in a flash helps us to separate danger from pleasantness. In fact, the brain is so keen on patterns that even where there are none at all, it stubbornly wants to make us believe that there are some (for example, when we look at the moon and see a face in it, or clouds look like animals to us).

This hyperpotent pattern recognition machine in our heads is now also the one that finally makes music out of tones: When a whole orchestra with 50 instruments thunders away, even the human brain is overwhelmed with translating the individual frequencies into tones, putting each one into a relationship with all the others as harmonies and simultaneously following the melody. What the brain ingeniously does instead is this: in this tsunami of tones, it looks for higher-level patterns and simply follows those. Thanks to this drastic reduction of complexity, the brain doesn't have to declare fortfait already with Christmas songs, but can give itself the most epic pieces and give us fullest pleasure in the process. To be precise: The pleasure is not a priori in the notes and sounds, but arises when cascades of neuronal fireworks of reward hormones go off in the brain, with which evolution rewards us for our ability to recognize patterns (i.e., in this case, harmonies). On the one hand, this ability is shaped by our origins - free jazz is not immediately obvious to everyone - and on the other hand, it is also shaped by our genes: because we pack not only eye color and stature into our genetic material, but also individual abilities to recognize pattern, it suddenly becomes understandable why music functions as a universal language. And the endorphins (the happiness hormones) bubble up really high when the piece hits exactly the sweet spot, where the beautiful order of sweet harmonies in the right places by spicy disharmonies swirled. Only harmony and no disharmony understrains the brain, while the opposite overstrains it. We experience music as an emotional sensation therefore most satisfying in the tension between complete predictability and total unpredictability.

In music lessons, not only finger skills are practiced, but also trained the senses that help us in dealing with other people. And it looks like this social component of frequencies and harmonies is to thank in good part for the privilege we have of experiencing sounds as music.

Video on the topic: http://youtu.be/i_0DXxNeaQ0

More resources:

http://www.quora.com/Why-do-certain-musical-notes-sound-good-together

http://www.ethanhein.com/wp/2013/can-science-make-a-better-music-theory-2/

http://www.quora.com/Can-Earworms-be-created-artificially

http://www.openculture.com/2014/09/why-we-love-repetition-in-music-explained-in-a-new-ted-ed-animation.html

Lehrer, Jonah (2008): Igor Stravinski. The Source of Musikc. In Proust Was a Neuroscientist, chapter 6. First Mariner Books. Boston, New York. Pp. 120-143.

Image: Gerardo Lazzari via http://www.imcreator.com/