By Dr. Mercola
It’s easy to take your hearing for granted, but the complex process that occurs when your ears pick up a sound and translate it into information your brain can understand is truly remarkable.
Interestingly, while some of your senses, like your sense of smell, vision, and taste, involve chemical reactions, your ability to hear does not. Instead, physical movements are responsible for your ability to hear.
How Hearing Works
Your ears capture sound traveling through the air as vibrations in air pressure. The outer part of your ear, or pinna, catches the sound waves first. The structure of your outer ear bounce sounds in different patterns depending on whether they come from behind you, above you or below you.
Your brain learns to recognize these distinctive patterns to alert you, first, where a sound is coming from. Your brain can also determine whether the sound is coming from the left or right depending on which ear it arrives at first. As noted by How Stuff Works:1
“Many mammals, such as dogs, have large, movable pinnae that let them focus on sounds from a particular direction. Human pinnae are not so adept at focusing on sound. They lay fairly flat against the head and don’t have the necessary muscles for significant movement.
But you can easily supplement your natural pinnae by cupping your hands behind your ears. By doing this, you create a larger surface area that can capture sound waves better.”
Your Fascinating Eardrum
Once sound waves pass your outer ear, they enter your ear canal and trigger vibrations to your eardrum, a thin piece of skin that sits between the ear canal and your middle ear.
Your eardrum vibrates faster from high-pitch sounds while loud sounds move your eardrum back-and-forth a greater distance. But it’s far from simply a passive part of the hearing process.
When your eardrum detects prolonged exposure to loud noises, for instance, a reflex occurs that makes your eardrum more rigid, meaning it essentially dampens the noise to protect your hearing.
This same reflex kicks in when you’re having a conversation in a noisy room, helping you to hear higher-pitched sounds while making the lower-pitched ones. The reflex also occurs when you speak so that the sound of your own voice doesn’t overtake all the other sounds around you.2
Once sound waves vibrate your eardrum, it moves a group of tiny bones in your middle ear called the malleus, the incus, and the stapes.
Collectively known as the ossicles, these are the smallest bones in your body, but they have a very important job – amplifying the force from your eardrum so the sound information can be passed on to your inner ear.
Sound in Your Inner Ear
The amplified vibrations from your eardrum travel to the cochlea in your inner ear, which conducts sound through fluid (instead of through air, as it done in your outer ear). It’s here that the sounds are translated into nerve impulses that your brain can…