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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 meant that you listened to the part about going to the fair and (maybe purposely) disregarded the bit about cleaning your room.

But actually it takes an incredible act of teamwork between your ears and your brain to have selective hearing.

The Stress Of Trying to Hear in a Crowd

This situation potentially seems familiar: you’re feeling tired from a long day at work but your friends all really want to go out for dinner and drinks. They decide on the loudest restaurant (because it’s popular and the deep-fried cauliflower is the best in town). And you spend an hour and a half straining your ears, attempting to follow the conversation.

But it’s difficult, and it’s taxing. And it’s a sign of hearing loss.

Perhaps, you rationalize, the restaurant was just too noisy. But no one else appeared to be having difficulties. It seemed like you were the only one experiencing trouble. Which gets you thinking: Why do ears that have hearing impairment have such a difficult time with the noise of a crowded room? Why is it that being able to hear in a crowd is so challenging? Scientists have started to discover the answer, and it all starts with selective hearing.

How Does Selective Hearing Operate?

The term “selective hearing” is a process that doesn’t even take place in the ears and is technically called “hierarchical encoding”. The majority of this process occurs in the brain. At least, that’s according to a new study done by a team at Columbia University.

Ears work just like a funnel as scientists have recognized for some time: they forward all of the raw data that they gather to your brain. In the auditory cortex the real work is then accomplished. That’s the part of your gray matter that handles all those signals, interpreting impressions of moving air into identifiable sounds.

Precisely what these processes look like was still unknown 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 works in terms of picking out voices in a crowd.

The Hierarchy of Hearing

And the facts they found are as follows: the majority of the work accomplished by the auditory cortex to isolate distinct voices is done by two separate parts. They’re what allows you to separate and amplify distinct voices in loud environments.

  • 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 individual voice and separates them into distinguishable identities.
  • Superior temporal gyrus (STG): At some point your brain will need to make some value based decisions and this is done in the STG after it receives the voices which were previously separated by the HG. The superior temporal gyrus figures out which voices you want to focus on and which can be securely moved to the background.

When you have hearing problems, your ears are lacking specific wavelengths so it’s more difficult for your brain to differentiate voices (high or low, based upon your hearing loss). Your brain can’t assign individual identities to each voice because it doesn’t have enough data. As a result, it all blends together (which makes conversations hard to follow).

New Science = New Algorithm

Hearing aids already have features that make it less difficult to hear in loud situations. But now that we know what the fundamental process looks like, hearing aid manufacturers can integrate more of those natural functions into their instrument algorithms. For instance, you will have a greater ability to hear and understand what your coworkers are talking about with hearing aids that assist the Heshl’s gyrus and do a little more to differentiate voices.

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