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 (perhaps deliberately) disregarded the bit about cleaning your room.
But in reality it takes an incredible act of teamwork between your brain and your ears to have selective hearing.
The Difficulty Of Trying to Hear in a Crowd
This scenario potentially feels familiar: you’ve had a long day at work, but your friends all insist on meeting up for dinner. They pick the noisiest restaurant (because they have incredible food and live entertainment). And you strain and struggle to follow the conversation for over an hour and a half.
But it’s difficult, and it’s taxing. And it’s an indication of hearing loss.
Perhaps, you rationalize, the restaurant was simply too loud. But… everyone else appeared to be having a fine go of it. You seemed like the only one having difficulty. So you start to ask yourself: Why do ears with hearing impairment have such a difficult 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 why? The solution, as reported by scientists, is selective hearing.
Selective Hearing – How Does it Work?
The term “selective hearing” is a process that doesn’t even take place in the ears and is technically known as “hierarchical encoding”. The majority of this process happens in the brain. At least, that’s according to a new study carried out by a team from Columbia University.
Scientists have recognized for some time that human ears essentially work like a funnel: they forward all of the unprocessed data that they collect to your brain. In the auditory cortex the real work is then accomplished. That’s the part of your gray matter that processes all those signals, translating impressions of moving air into recognizable sounds.
Just what these processes look like had remained a mystery despite the established knowledge of the role played by the auditory cortex in the process of hearing. Thanks to some novel research techniques involving 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 Hearing Hierarchy
And here’s what these intrepid scientists learned: there are two components of the auditory cortex that accomplish most of the work in helping you key in on specific voices. They’re what enables you to separate and enhance particular voices in noisy situations.
- Superior temporal gyrus (STG): The differentiated voices go from the HG to the STG, and it’s here that your brain begins to make some value distinctions. Which voices can be comfortably moved to the background and which ones you want to focused on is figured out by the STG..
- Heschl’s gyrus (HG): This is the region of the auditory cortex that takes care of the first phase of the sorting process. Heschl’s gyrus or HG processes each unique voice and separates them into discrete identities.
When you begin to suffer from hearing damage, it’s harder for your brain to distinguish voices because your ears are lacking certain wavelengths of sound (low or high, based upon your hearing loss). Your brain isn’t provided with enough data to assign individual identities to each voice. As a result, it all blurs together (which makes discussions tough to follow).
New Science = New Algorithm
Hearing aids already have features that make it less difficult to hear in noisy circumstances. 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 example, hearing aids that do more to differentiate voices can help out the Heschl’s gyrus a little, leading to a greater ability for you to comprehend what your coworkers are talking about in that loud restaurant.
Technology will get better at mimicking what occurs in nature as we learn more about how the brain works in combination with the ears. And that can result in better hearing outcomes. Then you can concentrate a little more on enjoying yourself and a little less on straining to hear.