Selective hearing is a phrase that commonly gets tossed about as a pejorative, an insult. Perhaps you heard your mother accuse your father of having “selective hearing” when she believed he might be ignoring her.
But actually selective hearing is quite the skill, an impressive linguistic feat conducted by teamwork between your brain and ears.
Hearing in a Crowd
Maybe you’ve dealt with this scenario before: you’re feeling burnt out from a long workday but your friends all really would like to go out for dinner and drinks. And of course, they want to go to the loudest restaurant (because it’s trendy and the deep-fried cauliflower is the best in town). And you strain and struggle to understand the conversation for over an hour and a half.
But it’s challenging, and it’s taxing. And it’s an indication of hearing loss.
You think, maybe the restaurant was just too loud. But no one else seemed to be struggling. The only one who appeared to be having difficulty was you. So you begin to wonder: what is it about the crowded room, the cacophony of voices all struggling to be heard, that causes hearing impaired ears to struggle? It seems like hearing well in a crowd is the first thing to go, but why? The answer, as reported by scientists, is selective hearing.
How Does Selective Hearing Function?
The phrase “selective hearing” is a task that doesn’t even occur in the ears and is technically called “hierarchical encoding”. This process almost completely occurs in your brain. At least, that’s in accordance with a new study performed by a team at Columbia University.
Scientists have known for quite a while that human ears essentially work like a funnel: they compile all the impulses and then send the raw data to your brain. That’s where the real work occurs, particularly the auditory cortex. Vibrations triggered by moving air are interpreted by this part of the brain into recognizable sound information.
Just what these processes look like had remained a mystery in spite of the existing knowledge of the role played by the auditory cortex in the hearing process. Scientists were able, by making use of unique research techniques on individuals with epilepsy, to get a better picture of how the auditory cortex discerns voices in a crowd.
The Hearing Hierarchy
And the facts they found are as follows: there are two parts of the auditory cortex that manage most of the work in helping you key in on particular voices. They’re what allows you to separate and amplify specific voices in loud settings.
- Superior temporal gyrus (STG): The separated voices move from the HG to the STG, and it’s here that your brain begins to make some value distinctions. The superior temporal gyrus determines which voices you want to give attention to and which can be confidently moved to the background.
- Heschl’s gyrus (HG): The first sorting stage is handled by this part of the auditory cortex. Heschl’s gyrus or HG processes each individual voice and separates them into distinguishable identities.
When you have hearing loss, your ears are lacking specific wavelengths so it’s harder for your brain to recognize voices (depending on your hearing loss it could be low or high frequencies). Your brain isn’t provided with enough information to assign separate identities to each voice. It all blurs together as a result (which means conversations will harder to follow).
New Science = New Algorithm
Hearing aids already have functions that make it less difficult to hear in noisy situations. But now that we know what the fundamental process looks like, hearing aid companies can integrate more of those natural operations into their instrument algorithms. For instance, you will have a better ability to hear and understand what your coworkers are talking about with hearing aids that help the Heshl’s gyrus and do a little more to distinguish voices.
Technology will get better at mimicking what occurs in nature as we discover more about how the brain functions in conjunction with the ears. And that can result in improved hearing success. That way, you can focus a little less on struggling to hear and a little more on enjoying yourself.