Hearing & The Brain
Once your ears have received incoming sounds and they’ve been converted into electrical impulses in the cochlea, the real work of hearing begins. Your brain then has to quickly unravel the complex nerve impulses, analyse them, and correctly interpret them.
Firstly, the auditory centre needs to break down the complex waveforms that arrive as neurological signals into pitch and volume. It then needs to compare the analysed waveforms with your stored patterns. This allows your brain to recognise the origin of a sound and the meaning behind it, for example, it works out whether a sound is speech or a potential danger signal. Background noise like the hum of a restaurant or the wind might be suppressed in your consciousness, while the voice of the person you’re talking to is filtered and amplified, allowing you to understand it better. This permanent and automatic assessment is essential, since you’re unable to focus on all the sounds around you.
The left hemisphere of the brain has the ability to choose between relevant and irrelevant noises, and although the brain usually decides automatically which sounds you should focus on. It’s also possible for you to influence it, by consciously focusing on a specific sound. So, for example you can listen to an individual voice in a room full of people, or to a single instrument in an orchestra.