Man can't hear in a crowded restaurant.

Sometimes when a person has a difficult time hearing, somebody close to them insultingly says they have “selective hearing”. Perhaps you heard your mother accuse your father of having “selective hearing” when she believed he might be ignoring her.

But in reality it takes an incredible act of cooperation between your brain and your ears to have selective hearing.

Hearing in a Crowd

Perhaps you’ve experienced this scenario before: you’re feeling tired from a long workday but your friends all really want to go out for dinner and drinks. They decide on the noisiest restaurant (because they have amazing food and live entertainment). And you spend an hour and a half straining your ears, working hard to follow the conversation.

But it’s difficult, and it’s taxing. This indicates that you could have hearing loss.

You think, maybe the restaurant was just too noisy. But no one else appeared to be struggling. The only person who appeared to be having trouble was you. Which gets you thinking: Why do ears that have hearing impairment have such a difficult time with the noise of a packed room? It seems as if hearing well in a crowded place is the first thing to go, but why? Scientists have started to discover the solution, and it all starts with selective hearing.

Selective Hearing – How Does it Work?

The phrase “selective hearing” is a process that doesn’t even occur in the ears and is formally known as “hierarchical encoding”. This process almost exclusively happens in your brain. At least, that’s in accordance with a new study carried out by a team from Columbia University.

Ears work like a funnel as scientists have known for quite a while: they forward all of the unprocessed data that they gather to your brain. That’s where the real work takes place, specifically the auditory cortex. Vibrations triggered by moving air are translated by this portion of the brain into perceptible sound information.

Because of substantial research with CT and MRI scans, scientists have recognized for years that the auditory cortex plays a considerable role in hearing, but they were stumped regarding what those processes really look like. Thanks to some novel research methods including participants with epilepsy, scientists at Columbia were able to discover more about how the auditory cortex functions in terms of picking out voices in a crowd.

The Hearing Hierarchy

And the insight they found are as follows: the majority of the work performed by the auditory cortex to isolate distinct voices is done by two different regions. And in noisy conditions, they allow you to separate and amplify specific voices.

  • Heschl’s gyrus (HG): The first sorting stage is taken care of by this part of the auditory cortex. Heschl’s gyrus or HG breaks down each unique voice and separates them into distinguishable identities.
  • Superior temporal gyrus (STG): The separated voices move from the HG to the STG, and it’s at this point that your brain starts to make some value distinctions. Which voices can be freely moved to the background and which ones you want to pay attention to is figured out by the STG..

When you start to suffer from hearing impairment, it’s harder for your brain to distinguish voices because your ears are lacking certain wavelengths of sound (low or high, based upon your hearing loss). Your brain can’t assign separate identities to each voice because it doesn’t have enough data. It all blends together as a consequence (which makes interactions difficult to follow).

A New Algorithm From New Science

It’s typical for hearing aids to come with features that make it easier to hear in a crowded situation. But hearing aid makers can now integrate more of those natural functions into their algorithms because they have a greater idea of what the process looks like. For example, hearing aids that do more to identify voices can assist the Heschl’s gyrus a little, leading to a better ability for you to understand what your coworkers are talking about in that noisy restaurant.

The more we learn about how the brain works, especially in conjunction with the ears, the better new technology will be capable of mimicking what happens in nature. And that can lead to better hearing outcomes. Then you can focus a little more on enjoying yourself and a little less on straining to hear.

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