Man can't hear in a crowded restaurant.

Selective hearing is a phrase that normally is used 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 it turns out that selective hearing is quite the ability, an amazing linguistic task executed by cooperation between your brain and ears.

The Stress Of Trying to Hear in a Crowd

Perhaps you’ve dealt with this situation before: you’re feeling tired from a long day at work but your friends all really want to go out for dinner and drinks. And of course, they want to go to the loudest restaurant (because it’s popular and the food 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. And it’s a sign of hearing loss.

Perhaps, you rationalize, the restaurant was simply too loud. But… everyone else seemed to be having a fine go of it. The only person who appeared to be having difficulty was you. Which gets you thinking: what is it about the crowded room, the cacophony of voices all struggling to be heard, that throws hearing-impaired ears for a loop? Just why is it that being able to hear in a crowd is so challenging? Scientists have begun to reveal the solution, and it all begins with selective hearing.

Selective Hearing – How Does it Work?

The scientific name for what we’re loosely calling selective hearing is “hierarchical encoding,” and it doesn’t take place in your ears at all. This process almost entirely occurs in your brain. At least, that’s in line with a new study carried out by a team at Columbia University.

Ears work just like a funnel as scientists have known for some time: they deliver all of the raw data that they collect to your brain. That’s where the heavy lifting occurs, particularly the auditory cortex. Vibrations triggered by moving air are translated by this part of the brain into recognizable sound information.

Exactly what these processes look like had remained a mystery in spite of the established understanding of the role played by the auditory cortex in the process of hearing. Scientists were able, by using novel 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 follows: most of the work done by the auditory cortex to isolate particular voices is accomplished by two different regions. And in loud settings, they allow you to separate and intensify particular voices.

  • Superior temporal gyrus (STG): The separated voices go from the HG to the STG, and it’s at this point that your brain begins to make some value determinations. Which voices can be freely moved to the background and which ones you want to pay attention to is figured out by the STG..
  • Heschl’s gyrus (HG): This is the region of the auditory cortex that deals with the first phase of the sorting routine. Researchers discovered that the Heschl’s gyrus (we’re just going to call it HG from here on out) was breaking down each distinct voice, separating them via unique identities.

When you begin to suffer from hearing damage, it’s more difficult for your brain to distinguish voices because your ears are lacking particular wavelengths of sound (high or low, based upon your hearing loss). Your brain can’t assign individual identities to each voice because it doesn’t have enough information. It all blurs together as a result (which makes discussions difficult to follow).

A New Algorithm From New Science

It’s common for hearing aids to come with functions that make it less difficult to hear in a crowd. But hearing aid manufacturers can now integrate more of those natural functions into their algorithms because they have a better concept of what the process looks like. For instance, you will have a greater ability to hear and understand what your coworkers are saying with hearing aids that assist the Heshl’s gyrus and do a little more to separate voices.

Technology will get better at mimicking what takes place in nature as we learn more about how the brain really works in conjunction with the ears. And that can result in better hearing success. Then you can concentrate a little more on enjoying yourself and a little less on straining to hear.

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