Have you ever wondered why your hearing can be so astute, why you’re able to distinguish between so many different sounds, or even when (relative to other senses) your sense of hearing develops? This is the sort of thing we’re curious about as well and even though our computers crunch through an extraordinary amount of data at Backtracks, there’s another piece of equipment which is equally impressive at sound processing — the human brain.
Our personal history of hearing
Human beings start listening to the world from a very early age — right before they’re born. Our experiences inside the womb say a lot about how we perceive the world through sound, and how these sounds can train us to act differently depending on our culture. Investigations into human hearing have found that the most important listening organ is not our ears but our brains, and our brains play a central role in our developmental understanding of language. Additionally, the physical structure of our ears is an important contributor to the kinds of sounds we can detect, and goes a long way to explaining why there is an immense range of different sounds that animals can hear.
So when in our lives does the listening process actually start? Physically, it can start as early as 3–4 weeks in the womb when our cells start to arrange themselves into recognizable features such as our ears, brain, and other senses. By the time a baby is around five and a half months in the womb, it can become a lot more sensitive to sounds, being able to differentiate between sound types. Since a baby’s heart rate increases at the sound of its mother’s voice, there’s a strong suggestion that babies become sensitive early on to tone and pitch.
The brain, language, and cultural conditioning
Even though the ear is the organ through which sound enters our bodies, the main work in translation and interpretation is done in the brain. As we age, we often hear it said that our hearing deteriorates and while this is true, it’s not necessarily for the reasons we may think. As our bodies grow older, so do our brains, and the older we get, the less effective they become at interpreting noise. A common example among the elderly is the inability to hear well in a crowded environment: this is because the brain is becoming less capable of distinguishing between the ruckus of different sounds in the vicinity.
The brain plays an immensely important role in language and our cognition of it. For instance, even though the English language has 26 letters, it is made up of 44–46 different types of sounds. Chinese, however, has around 412 different sound combinations. All this comprehension work is done in two distinct areas of the brain called Broca’s Area and Wernicke’s Area. The first deals with how we produce speech and how we form sounds. The latter, Wernicke’s Area, is concerned with how we understand and interpret language. Conversely, if we sustain physical damage to either of these areas of the brain, our ability to speak coherently or to understand language is affected relatively.
Humans can hear a huge range of sounds, picking up vibrations between 20Hz and 20,000Hz. However, this scale does not cover our entire range of cognition and there are arguments to say that there is a difference between hearing sound and perceiving it. If we take the latter into consideration, we can detect sounds down to even 8Hz as long as they are loud enough.
Our environments and our perception of them assist in cultural conditioning. Studies have found that babies born in different countries cry differently. In France, babies tend to raise the pitch of a cry towards the end, in keeping with how French speakers tend to end sentences with a high tone. This is in contrast to German babies who lower the tone of their cry towards the end, in keeping with how German natives intonate their speech. Therefore, even before birth, we absorb multiple sounds from our environments and this explains why we sometimes feel ‘out of place’ among the sounds of unfamiliar locales or communities. Likewise, music which is familiar to us can have a homely, calming effect, whereas music which is unfamiliar or native to different cultures can seem unusual or bizarre.
We never stop listening
Before birth, we take in vibrations all around us, from inside and outside the womb. Sound accompanies us all through our day, from the loudest moments to the quietest. With a sense of hearing, there does not appear to be such a thing as true silence, since we can always hear our heartbeat or the sounds of blood rushing through our bodies.
The science of sound and listening is always close to us, and here at Backtracks, we enjoy discovering more about this science and its corresponding data and hope you enjoyed this article.