Man can't hear in a crowded restaurant.

Sometimes when an individual has a hard time hearing, somebody close to them insultingly says they have “selective hearing”. When your mother used to accuse you of having “selective hearing,” she was suggesting that you listened to the part about going to the fair and (maybe deliberately) ignored the bit about doing your chores.

But actually selective hearing is quite the skill, an impressive linguistic task conducted by teamwork between your ears and brain.

Hearing in a Crowd

Maybe you’ve experienced this situation before: you’ve been through a long day at work, but your friends all insist on meeting up for dinner. They pick the loudest restaurant (because it’s popular and the food is delicious). And you strain and struggle to follow the conversation for the entire evening.

But it’s challenging, and it’s taxing. And it’s an indication of hearing loss.

You think, perhaps the restaurant was simply too loud. But… everyone else appeared to be having a fine go of it. It seemed like you were the only one having trouble. So you begin to wonder: Why do ears with hearing impairment have such a hard 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 what’s the reason? The solution, according to scientists, is selective hearing.

How Does Selective Hearing Work?

The scientific term 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 completely occurs in your brain. At least, that’s as reported by a new study carried out by a team at Columbia University.

Ears work just like a funnel which scientists have recognized for quite a while: they forward all of the unprocessed data that they collect to your brain. That’s where the real work happens, specifically the auditory cortex. Vibrations caused by moving air are translated by this portion of the brain into recognizable sound information.

Precisely 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. Thanks to some innovative research techniques concerning participants with epilepsy, scientists at Columbia were able to discover more about how the auditory cortex functions in relation to picking out voices in a crowd.

The Hearing Hierarchy

And here’s what these intrepid scientists found: most of the work performed by the auditory cortex to pick out particular voices is done by two different parts. They’re what allows you to sort and intensify distinct voices in noisy situations.

  • 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 determinations. Which voices can be comfortably moved to the background and which ones you want to focused on is determined by the STG..
  • Heschl’s gyrus (HG): This is the part of the auditory cortex that takes care of the first stage of the sorting process. Scientists found that the Heschl’s gyrus (we’re simply going to call it HG from here on out) was breaking down each individual voice, classifying them via unique identities.

When you have hearing problems, your ears are missing particular wavelengths so it’s more difficult for your brain to distinguish voices (high or low, based upon your hearing loss). Your brain isn’t furnished with enough data to assign individual identities to each voice. Consequently, it all blurs together (meaning discussions will more difficult to understand).

New Science = New Algorithm

It’s common for hearing aids to have functions that make it less difficult to hear in a crowded situation. But now that we know what the basic process looks like, hearing aid manufacturers can incorporate more of those natural functions into their device algorithms. For example, you will have a greater ability to hear and comprehend what your coworkers are saying with hearing aids that assist the Heshl’s gyrus and do a little more to differentiate voices.

The more we discover about how the brain works, specifically in connection with the ears, the better new technology will be able to mimic what takes place in nature. And better hearing success will be the result. Then you can focus a little more on enjoying yourself and a little less on straining to hear.

The site information is for educational and informational purposes only and does not constitute medical advice. To receive personalized advice or treatment, schedule an appointment.
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