Man can't hear in a crowded restaurant.

Selective hearing is a term that commonly gets tossed about as a pejorative, an insult. Perhaps you heard your mother suggest that your father had “selective hearing” when she thought he might be ignoring her.

But actually selective hearing is quite the skill, an amazing linguistic accomplishment carried out by cooperation between your ears and brain.

Hearing in a Crowd

This situation potentially seems familiar: you’ve had a long day at work, but your buddies all insist on going out to dinner. And naturally, they want to go to the noisiest restaurant (because it’s trendy and the food is delicious). And you spend the entire evening straining your ears, attempting to follow the conversation.

But it’s very difficult and exhausting. This indicates that you could have hearing loss.

You think, perhaps the restaurant was simply too noisy. But no one else appeared to be struggling. The only person who appeared to be having difficulty was you. Which makes you think: Why do ears with hearing impairment have such a hard time with the noise of a crowded room? Just why is it that being able to hear in a crowd is so quick to go? The answer, according to scientists, is selective hearing.

How Does Selective Hearing Function?

The scientific name for what we’re broadly 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 performed by a team from Columbia University.

Ears work like a funnel as scientists have recognized for some time: they deliver all of the raw data that they collect to your brain. That’s where the heavy lifting occurs, specifically the auditory cortex. That’s the part of your gray matter that handles all those signals, interpreting impressions of moving air into recognizable sounds.

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

The Hierarchy of Hearing

And the information they found out are as follows: there are two regions of the auditory cortex that perform most of the work in allowing you to key in on particular voices. They’re what enables you to separate and enhance particular voices in loud environments.

  • 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 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 process. Heschl’s gyrus or HG processes each individual voice and separates them into discrete identities.

When you have hearing impairment, your ears are missing particular wavelengths so it’s more difficult for your brain to differentiate voices (depending on your hearing loss it could be high or low frequencies). Your brain can’t assign separate identities to each voice because it doesn’t have enough information. It all blurs together as a consequence (which makes discussions tough to follow).

New Science = New Algorithm

It’s typical for hearing aids to come with functions that make it easier to hear in a crowded situation. But now that we understand what the fundamental process looks like, hearing aid manufacturers can incorporate more of those natural functions into their device algorithms. For example, you will have a better capacity to hear and comprehend what your coworkers are talking about with hearing aids that help the Heshl’s gyrus and do a little more to differentiate voices.

Technology will get better at mimicking what occurs in nature as we discover more about how the brain really works in combination with the ears. And that can result in improved hearing outcomes. That way, you can concentrate a little less on struggling to hear and a little more on enjoying yourself.

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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