Maybe you’ve heard that dogs with floppy ears can’t hear as well as those with pointed ones. You’re likely not surprised that cats, dogs, and hamsters can change the direction that their ears face to better pick up sound from the front, sides or back.
Our fuzzy pets aren’t the only ones whose ears impact the way they hear. The human ear has similar features are it can vary among humans.
Let’s explore how your ear’s shape may impact your hearing and look at how this new finding may impact hearing loss treatments over the next decade.
Outer Ear Shape Science
The outer ear is composed of the part that you see and call your ear. This is called the “auricle” or “pinna.” The outer ear also includes the ear canal that leads into the middle ear.
We’ve learned since elementary science class that the inner ear is where hearing takes place. Your auricle could be damaged in an accident. As long as the canal stays intact and the middle and inner continue working you would still hear.
You might choose to have a cosmetic procedure to reduce ear prominence. Common knowledge was that this didn’t change hearing in the least.
Does this make the auricle the most useless part of our anatomy? Is its only job just to funnel sound into the ear canal? Or is its purpose more subtle and incredibly important?
Researchers got curious. They started asking questions. In science, this is when new discoveries take place. Such is the case with auricle part of your outer ear.
The study’s findings were published this month in the Journal of Neuroscience.
What Researchers Found
Science already knows that our brains can tell where a sound is coming from based on which ear the sound wave hits first. A person with two fully functioning ears can usually quickly determine if a sound came from the left or right. But what is the purpose of the interesting shape of your auricle?
To find out, the scientists temporarily changed the shape of study participants’ outer ears. To do this, they inserted flexible silicone into the grooves of the auricle — not in the ear canal. That would be dangerous.
When they did so, they found that people could still tell the direction the sound came from, but they couldn’t tell if the sound came from above their head or under the furniture.
They had just lost a previously unknown piece of the human ear’s geo-location system.
How the Study Was Conducted
Scientists use an fMRI machine to measure brain activity. Participants were asked to listen to sounds before modification to determine how their brains reacted as they located the sound.
Scientists noted the neurons fired more quickly when the sound was below them and slowly when it was above.
Once the participants had the molds in, they were asked to locate where the sound was coming from again. Overwhelmingly, the participants could no longer say. They thought sounds from up high were below them and vice versa. The neurons in their brains were firing in seemingly random ways — as if confused.
They asked the participants to wear the ear molds for a week and then follow up for further tests. Interestingly, their geo-location system had adapted and could again tell where sounds were coming from.
When the molds were removed their brains returned to normal.
This demonstrates that hearing is much more than just sound hitting your eardrum on its way to the cochlea. How it interacts with the outer ear allows the brain to understand more about that sound than we previously realized.
Why Audiologists Are So Interested in This Study
Audiologists are doctors who diagnose and treat hearing loss and balance problems. For both of these senses, the inner ear is vital. This new study further explains how the parts of our ears work together to understand what we’re hearing.
Through research like this, Audiologists hope to find new and better ways to treat hearing loss. Hearing aid technology has advanced significantly over just the past 10-20 years. As we continue to learn more, we’ll be able to make the hearing aid experience even better.
We look forward to seeing how this new finding impacts hearing loss treatments and hearing aid technology.