Selective hearing is a term that usually is used as a pejorative, an insult. When your mother used to accuse you of having “selective hearing,” she meant that you paid attention to the part about chocolate cake for dessert and (perhaps intentionally) disregarded the part about cleaning your room.
But actually selective hearing is quite the skill, an impressive linguistic accomplishment executed by teamwork between your ears and brain.
The Difficulty Of Trying to Hear in a Crowd
This situation probably feels familiar: you’ve been through a long day at work, but your buddies all insist on meeting up for dinner. And naturally, they want to go to the loudest restaurant (because they have amazing food and live entertainment). And you strain and struggle to understand the conversation for over an hour and a half.
But it’s very difficult and exhausting. And it’s an indication of hearing loss.
You think, perhaps the restaurant was just too noisy. But no one else appeared to be struggling. The only person who appeared to be having difficulty was you. Which makes you think: Why do ears that have hearing impairment have such a hard time with the noise of a packed room? Just why is it that being able to hear in a crowd is so challenging? The answer, according to scientists, is selective hearing.
Selective Hearing – How Does it Work?
The term “selective hearing” is a task that doesn’t even occur in the ears and is technically known as “hierarchical encoding”. The majority of this process occurs in the brain. At least, that’s in accordance with a new study carried out by a team at Columbia University.
Ears work just like a funnel which scientists have understood for quite a while: they collect all the signals and then send the raw data to your brain. In the auditory cortex the real work is then accomplished. Vibrations caused by moving air are translated by this portion of the brain into recognizable sound information.
Exactly what these processes look like was still unknown despite the established knowledge of the role played by the auditory cortex in the process of hearing. Scientists were able, by utilizing novel research techniques on people with epilepsy, to get a better picture of how the auditory cortex picks out voices in a crowd.
The Hierarchy of Hearing
And the facts they found are as follows: the majority of the work accomplished by the auditory cortex to pick out distinct voices is accomplished by two separate regions. And in loud conditions, they allow you to separate and boost certain voices.
- Superior temporal gyrus (STG): The separated voices go from the HG to the STG, and it’s at this point that your brain starts to make some value distinctions. The superior temporal gyrus determines which voices you want to pay attention to and which can be confidently moved to the background.
- Heschl’s gyrus (HG): This is the region of the auditory cortex that deals with the first phase of the sorting process. Heschl’s gyrus or HG processes each unique voice and separates them into discrete identities.
When you have hearing loss, your ears are lacking particular wavelengths so it’s harder for your brain to differentiate voices (depending on your hearing loss it might be low or high frequencies). Your brain can’t assign individual identities to each voice because it doesn’t have enough information. It all blurs together as a consequence (which makes conversations difficult to follow).
New Science = New Algorithm
Hearing aids currently have features that make it less difficult to hear in noisy settings. But hearing aid manufacturers can now integrate more of those natural functions into their algorithms because they have a better idea of what the process looks like. As an example, hearing aids that do more to differentiate voices can assist the Heschl’s gyrus a little bit, resulting in a greater capacity for you to understand what your coworkers are saying in that noisy restaurant.
The more we discover about how the brain works, particularly in conjunction with the ears, the better new technology will be able to mimic what takes place in nature. And that can lead to better hearing outcomes. That way, you can concentrate a little less on struggling to hear and a little more on enjoying yourself.