How Hearing Works
Hearing is one of the more complicated senses to understand in terms of how it works. Hearing sound means that the ear must translate sound waves into mechanical signals in the form of vibrations, which in turn are translated into electrical impulses so that the brain can process the information.
The ear is made out of three parts: the outer ear, the middle ear, and the inner ear.
- Outer Ear: Is the part of the ear that is visible when you look at someone. It works to funnel sound into the auditory canal. The auditory canal, also part of the outer ear, is the part of the ear hole that can be seen when looking at the ear.
- Middle Ear: The middle ear consists of the three middle ear bones, the malleus (hammer), incus (anvil), and stapes (stirrup). These tiny bones are responsible for translating sound waves into vibrations.
- Inner Ear: The inner ear consists of the cochlea, which is a fluid-filled, spiral-shaped structure that has the receptor organ for hearing. Tiny hair cells inside the cochlea translate the vibrations into electrical signals that are brought to the brain through nerves.
Our hearing depends on these parts of the ear to working together. If there is a problem anywhere along this process, you may experience hearing loss.
WHAT IS SOUND?
When something makes a sound — whether it’s someone talking, wind howling, or an item falling onto the floor — it creates an invisible vibration in the air. This vibration is called a sound wave. The force and energy in a sound wave carries through the air in all directions from the source of the noise. The further it travels, the more the vibrations decrease.
Everything that we associate with the nature of sound is carried by these vibrations. Things like pitch, volume, frequency, and so on can be seen when you look at measurements of sound waves. You will see that there are more densely packed vibrations or further apart; they can have taller or shorter sound waves, and so on.
The distinctions in the sound waves is not something that humans can see, but our ears and our brains have biological mechanisms to process them. That is how we can hear the differences in how loud something is, or how we can note the slight differences between different people’s voices.
HOW WE PROCESS SOUND
There are two important parts for how we receive and process these sound waves: the physical element, and the psychological element.
The physical element has to do with when the sound waves reach our ears. The vibrations are funneled from our outer ear into our middle and inner ear, and stimulate the very delicate nerves in our inner ears. These nerves are what is able to process all of the distinctions and differences in the vibrations.
The psychological element starts when the nerves in our ears send signals to our brain about the sounds they hear. There are a few important parts of our brain that contribute to how we process and understand the sound our ears pick up. It is how we are able to understand the difference between talking or singing, male or female voices, and glass or wood breaking.
When we lose the ability to hear clearly, it is because our ears and/or brains have lost some of their normal ability to receive and process sound waves. There are different hearing tests that can tell exactly how much hearing ability you have lost, as well as what part of hearing has been reduced.
Click here to learn more about the different types, causes or symptoms of hearing loss.