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Man can't hear in a crowded restaurant.

Sometimes when an individual has a hard time hearing, someone 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 paid attention to the part about going to the fair and (maybe deliberately) disregarded the part about cleaning your room.

But it turns out that selective hearing is quite the talent, an amazing linguistic task executed by teamwork between your brain and ears.

Hearing in a Crowd

This situation potentially feels familiar: you’re feeling tired from a long workday 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 spend an hour and a half straining your ears, working hard to follow the conversation.

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

You think, maybe the restaurant was just too loud. But no one else seemed to be struggling. It seemed like you were the only one experiencing difficulty. So you begin to wonder: Why do ears with hearing impairment have such a difficult 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 solution, as reported by scientists, is selective hearing.

How Does Selective Hearing Function?

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

Scientists have recognized for some time that human ears basically work as a funnel: they collect all the signals and then send the raw information to your brain. In the auditory cortex the real work is then accomplished. Vibrations triggered by moving air are interpreted by this part of the brain into perceptible sound information.

Because of substantial research with CT and MRI scans, scientists have recognized for years that the auditory cortex plays a substantial role in hearing, but they were clueless with regards to what those processes really look like. 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 here’s what these intrepid scientists discovered: there are two regions of the auditory cortex that perform most of the work in allowing you to key in on specific voices. They’re what enables you to sort and enhance specific voices in loud environments.

  • Superior temporal gyrus (STG): Eventually your brain will need to make some value based choices and this occurs 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 focus on and which can be safely moved to the background.
  • Heschl’s gyrus (HG): This is the part of the auditory cortex that deals with the first stage of the sorting process. Researchers discovered that the Heschl’s gyrus (we’re simply going to call it HG from here on out) was processing each distinct voice, separating them into unique identities.

When you have hearing loss, your ears are missing specific wavelengths so it’s more difficult for your brain to recognize voices (depending on your hearing loss it might be low or high frequencies). Your brain can’t assign individual identities to each voice because it doesn’t have enough data. Consequently, it all blends together (which means conversations will more difficult to follow).

A New Algorithm From New Science

It’s common for hearing aids to have features that make it easier 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 idea of what the process looks like. For instance, you will have a better ability to hear and comprehend what your coworkers are talking about with hearing aids that assist the Heshl’s gyrus and do a little more to identify voices.

The more we find out about how the brain works, specifically in connection with the ears, the better new technology will be capable of mimicking 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.