Hearing Health Blog

Man can't hear in a crowded restaurant.

Selective hearing is a phrase that commonly gets tossed about 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 in reality it takes an amazing act of cooperation between your ears and your brain to have selective hearing.

The Stress Of Trying to Hear in a Crowd

Perhaps you’ve experienced this situation before: you’re feeling burnt out from a long day at work but your friends all really would like to go out for dinner and drinks. They decide on the loudest restaurant (because it’s popular and the deep-fried cauliflower is delicious). And you spend an hour and a half straining your ears, trying to follow the conversation.

But it’s very difficult and exhausting. And it’s an indication of hearing loss.

Perhaps, you rationalize, the restaurant was just too noisy. But… everyone else appeared to be having a great time. It seemed like you were the only one experiencing difficulty. Which makes you think: Why do ears that have hearing impairment have such a difficult time with the noise of a crowded room? It seems like 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.

Selective Hearing – How Does it Work?

The scientific name for what we’re broadly calling selective hearing is “hierarchical encoding,” and it doesn’t happen inside of your ears at all. The majority of this process occurs in the brain. At least, that’s in accordance with a new study done by a team from Columbia University.

Scientists have known for some time that human ears essentially work as a funnel: they forward all of the raw data that they gather to your brain. That’s where the heavy lifting occurs, specifically the auditory cortex. That’s the part of your brain that processes all those impulses, interpreting sensations of moving air into perceptible sounds.

Because of comprehensive research with CT and MRI scans, scientists have understood for years that the auditory cortex plays a crucial role in hearing, but they were clueless with regards to what those processes actually 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 when it comes to discerning voices in a crowd.

The Hearing Hierarchy

And the insight they discovered are as follows: there are two components of the auditory cortex that manage most of the work in allowing you to identify particular voices. And in loud settings, they allow you to isolate and amplify particular voices.

  • Heschl’s gyrus (HG): The first sorting phase is handled by this part of the auditory cortex. Heschl’s gyrus or HG breaks down each unique voice and separates them into distinct identities.
  • Superior temporal gyrus (STG): At some point your brain needs to make some value based decisions and this is done in the STG after it receives the voices which were previously differentiated by the HG. The superior temporal gyrus figures out which voices you want to give attention to and which can be safely moved to the background.

When you have hearing problems, your ears are lacking particular wavelengths so it’s harder for your brain to differentiate voices (depending on your hearing loss it might be low or high frequencies). Your brain isn’t provided with enough data to assign individual identities to each voice. Consequently, it all blurs together (which makes discussions tough to follow).

New Science = New Algorithm

It’s standard for hearing aids to come with functions that make it easier to hear in a crowded situation. But now that we know what the basic process looks like, hearing aid companies can incorporate more of those natural operations into their device algorithms. For instance, you will have a better ability to hear and understand what your coworkers are talking about 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 uncover more about how the brain functions in combination with the ears. And that can lead to improved hearing success. That way, you can concentrate a little less on straining to hear and a little more on enjoying yourself.

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