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Man can't hear in a crowded restaurant.

Selective hearing is a phrase that usually is used as a pejorative, an insult. When your mother used to accuse you of having “selective hearing,” she was suggesting that you listened to the part about chocolate cake for dessert and (perhaps purposely) disregarded the part about cleaning your room.

But it turns out that selective hearing is quite the ability, an amazing linguistic task performed by cooperation between your brain and ears.

The Stress Of Trying to Hear in a Crowd

This scenario potentially feels familiar: you’re feeling tired from a long workday but your friends all really want to go out for dinner and drinks. They pick the loudest restaurant (because it’s popular and the deep-fried cauliflower is the best in town). And you strain and struggle to understand the conversation for the entire evening.

But it’s difficult, and it’s taxing. This suggests that you might have hearing loss.

You think, perhaps the restaurant was simply too noisy. But no one else appeared to be having difficulties. It seemed like you were the only one having trouble. So you start to wonder: what is it about the crowded room, the cacophony of voices all battling to be heard, that causes hearing impaired ears to struggle? It seems as if hearing well in a crowd is the first thing to go, but what’s the reason? The solution, according to scientists, is selective hearing.

How Does Selective Hearing Operate?

The phrase “selective hearing” is a task that doesn’t even take place in the ears and is scientifically called “hierarchical encoding”. This process nearly exclusively occurs in your brain. At least, that’s in line with a new study performed by a team from Columbia University.

Ears work like a funnel which scientists have understood for some time: they send all of the unprocessed data that they collect to your brain. That’s where the real work takes place, specifically the auditory cortex. That’s the part of your gray matter that processes all those impulses, interpreting impressions of moving air into perceptible sounds.

Because of considerable research with CT and MRI scans, scientists have known for years that the auditory cortex plays a considerable role in hearing, but they were stumped regarding what those processes actually look like. Thanks to some unique research methods including participants with epilepsy, scientists at Columbia were able to learn more about how the auditory cortex functions in relation to discerning voices in a crowd.

The Hearing Hierarchy

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 different regions. And in noisy environments, they allow you to separate and amplify specific voices.

  • Superior temporal gyrus (STG): The differentiated 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 figures out which voices you want to give attention to and which can be safely moved to the background.
  • Heschl’s gyrus (HG): The first sorting stage is managed by this region of the auditory cortex. Heschl’s gyrus or HG breaks down each unique voice and separates them into distinguishable identities.

When you begin to suffer with hearing impairment, it’s more difficult for your brain to differentiate voices because your ears are missing particular wavelengths of sound (depending on your hearing loss it could be low or high frequencies). Your brain can’t assign separate identities to each voice because it doesn’t have enough information. As a result, it all blends together (meaning interactions will harder to understand).

A New Algorithm From New Science

It’s typical for hearing aids to have features that make it less difficult to hear in a crowd. But hearing aid manufacturers can now incorporate more of those natural functions into their algorithms because they have a greater idea of what the process looks like. For example, you will have a better capacity to hear and comprehend what your coworkers are saying 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 learn more about how the brain functions in combination with the ears. And that can result in better hearing success. Then you can focus a little more on enjoying yourself and a little less on straining to hear.