How we Hear: Recreating the World through Sound

“Sound is a psychological concept, a product of brains”.

(Daniel Levitan 2024, p.21)

We commonly think of sound as a product of the world ‘out there’, of the external world ‘as it is’. Yet, research shows this is not the case. In fact, we don’t experience an external sound, but the interpretation of information (waves or frequencies in the air) which are interpreted by our ears, converted into electrical impulses, and processed by the brain. It is more correct to say that sound occurs in our brains as a psychological phenomenon.

How we Hear

“Perception of sound begins at our eardrum- before it hits our eardrums, it is nothing more than the disturbance of molecules”.  (Daniel Levitan 2024, p.20)

Sound is a complex mixture of pressure variations that travel as invisible waves, beginning as the disturbance of molecules within a medium such as air, water, steel, or wood. In fact, sound and colour was noted by Isaac Newtown as being soundless or colourless until it reaches the brain of a living organism (Levitan 2024, p.20)

Figure 1.1: Perception of Sound (World Health Organisation)

Sound waves reach the ear, and are funnelled into the ear canal by the Pinna. The waves travel down the eardrum causing the eardrum to oscillate. The vibrations are transmitted by the ossicles (made of three small bones- hammer, anvil and stirrup) and sent to the cochlea. Within the cochlea, the vibrations cause movement of fluid and hair cells. The outer hair cells amplify the waves towards the inner hair cells, which convert the waves into electrical signals to be sent to the brain. The brain interprets these signals as sounds that can be recognised and understood (Krug et.al 2015).

The organ that is responsible for transforming sound waves into neural signals is called the organ of Corti (Cousto 2000, p.14). The Corti organ looks like a harp, made of thousands of hairs of different lengths, known as cilia, which vibrate to differing wave frequencies. This means that waves are distinguished by frequency (pitches) and stimulate hairs accordingly. Thus, a piece of music is recreated by the Corti organ and the oscillations of the cilia are transformed into electrical impulses for the brain. The brain decodes all the properties of sound including pitch, duration, loudness, and features of direction (Levitan 2024, p.23).

In a similar way,  light is interpreted by the eyes and converted into electrical signals sent to the brain to produce vision (Cousto 2000, p.14). Both sound and vision are made of  frequency information coexisting on the same spectrum. Sound is in the range of 20-20,000 Hertz, while vision is in a higher range of 375 trillion hertz – 750 trillion hertz. This means that as we ascend up the frequency spectrum, sound turns into colour, since they comprise the same substance at a different rates of vibration.

“In a physical sense, there is no such thing as color. Instead, there are only combinations of waves perceived as color, depending on the wave lengths and frequencies involved, as well as subjective factors. The same applies to sound.” (Cousto 2000, p.16)

Different species have different hearing ranges. For example, bats can hear frequencies up to 100,000 hertz, way beyond human hearing which maximises at 20,000 hertz (Cousto 2000, p.16). This illustrates how our hearing capabilities provide different species with different experiences of the world.  

“There is no such thing as sound... There are only frequencies. We can "hear" some of them because our ears have the ability to resonate to the range of the frequency involved.”(Cousto 2000, p.17)

A Philosophy of Sound

Knowledge of sound and its biological mechanisms pose an interesting question about the nature of reality: whether the world exists as we perceive it. Based on our knowledge of how the ear and eye interpret the world as information within our brains, we should conclude that the world is a representation created inside our brains. This is a question that Becker (2004, p.109) analyses, starting with the premise that we are commonly taught to think of the world as an objective place ‘outside’ of ourselves that has definable properties. She suggests that musical experience can easily subvert these common understandings, making music critical for the study of philosophy and perception.  

 Our biological and neurological knowledge confirms that we are not experiencing the objective world, but an interpretation of it. But this way of thinking suggests that “all is in our minds” as projection, leading to the view that “I’m the only one that exists”. Becker (2004, p.109) opts for a middle ground position, that the world emerges from a combination of cognitive perception and action. This entails that we are experiencing a combination of information from ‘outside’, but interpreted ‘inside’, and mixed with our prior subjective conditioning and subsequent action in the world.

In my fieldwork with afro-Cuban Santeria rituals, I had to navigate the belief in a supernatural world of deities that could possess human bodies. This conflicted with my own views about the sovereignty of the individual soul, derived primarily from a Christian legacy. It wasn’t until I began participating physically within rituals that the conflict intensified, as my worldview was challenged. Beliefs alone were not enough to stimulate me emotionally, until I ‘made real’ that world through action. After participating in rituals through action, subsequent hearing of the music of Santeria brought back the vivid experience of their supernatural cosmology and the emotions associated with it. This is why ritual participation is critical, because it’s effects depend on beliefs solidified through recreation of the world using the body. It is true that we construct the world with our brains, but we also act within those worlds to create meaning, and sound evokes the whole cosmology, its accompanying emotion, and behaviour (Becker 2004 p.115)

Recreating the World through Sound and Body

In summary, sound is an interpretation of waves recreated within the ear canal, turned into electrical impulses and sent to the brain for processing. We ‘create’ sound in the brain as a psychological process. This may cause us to think that reality is a product of our minds, a projection that has no real-world objectivity and contrary to the commonly held idea of world as external objective place. We can find a middle path between these two views, which considers the ‘external’ impressions and ‘internal’ recreations coloured by our subjective conditioning, and ‘made real’ through action. We take this understanding from our knowledge of how sound and vision work. The ear takes information from an external world and recreates it within. We then ‘act’ in the world based on these impressions which are comixed with our subjective biases and conditioning. In other words, we recreate a version of the world within, and then solidify the world ‘out there’ through active participation.

References

Becker, J., 2004. Deep listeners: Music, emotion, and trancing (Vol. 2). Indiana University Press.

Krug, E., Cieza, M. A., Chadha, S., Sminkey, L., Morata, T., Swanepoel, D., Fuente, A., Williams, W., Cerquone, J., Martinez, R., Stevens, G., Peden, M., Rao, S., Agarwal, P., Zeeck, E., Bladey, A., Arunda, M., & Ncube, A. (2015). How we hear. In Hearing loss: due to recreational exposure to loud sounds (pp. 1–2). World Health Organization. http://www.jstor.org/stable/resrep40742.5

Cousto, H. (2000) The Cosmic Octave, Life rhythm, USA.

Levitin, D. (2024) Music as Medicine. Cornerstone Press, Penguin Books, UK