Sometimes when a person 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 was suggesting that you paid attention to the part about chocolate cake for dessert and (maybe purposely) ignored the part about doing your chores.
But actually it takes an incredible act of cooperation between your brain and your ears to have selective hearing.
The Stress Of Trying to Hear in a Crowd
This situation probably feels familiar: 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. And naturally, they want to go to the noisiest restaurant (because they have incredible food and live entertainment). And you spend the entire evening straining your ears, trying to follow the conversation.
But it’s tough, and it’s taxing. This indicates that you might have hearing loss.
You think, perhaps the restaurant was just too noisy. But no one else seemed to be having difficulties. It seemed like you were the only one having difficulty. Which gets you thinking: Why do ears that have 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 what’s the reason? Scientists have started to discover the answer, and it all starts with selective hearing.
Selective Hearing – How Does it Work?
The scientific term for what we’re loosely calling selective hearing is “hierarchical encoding,” and it doesn’t happen inside of your ears at all. Most of this process occurs in the brain. At least, that’s in accordance with a new study carried out by a team at Columbia University.
Scientists have recognized for quite some time that human ears essentially work like a funnel: they send all of the unprocessed data that they collect to your brain. That’s where the real work happens, particularly the auditory cortex. That’s the part of your brain that processes all those impulses, translating sensations of moving air into recognizable sounds.
Just what these processes look like had remained a mystery despite the existing knowledge of the role played by the auditory cortex in the hearing process. Thanks to some novel research techniques concerning participants with epilepsy, scientists at Columbia were able to find out more about how the auditory cortex functions in relation to discerning voices in a crowd.
The Hearing Hierarchy
And the facts they found out follows: there are two parts of the auditory cortex that accomplish most of the work in allowing you to key in on specific voices. They’re what allows you to sort and amplify specific voices in loud environments.
- Heschl’s gyrus (HG): The first sorting phase is managed by this region of the auditory cortex. Heschl’s gyrus or HG processes each unique voice and separates them into distinct identities.
- Superior temporal gyrus (STG): Eventually your brain will need to make some value based decisions and this happens 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 give attention to and which can be confidently moved to the background.
When you start to suffer with hearing impairment, it’s harder for your brain to identify voices because your ears are lacking certain wavelengths of sound (low or high, depending on your hearing loss). Your brain can’t assign separate identities to each voice because it doesn’t have enough information. It all blends together as a consequence (which makes conversations tough to follow).
A New Algorithm From New Science
It’s standard for hearing aids to have features that make it less difficult to hear in a crowd. But now that we know what the fundamental process looks like, hearing aid companies can incorporate more of those natural functions into their device algorithms. As an example, hearing aids that do more to differentiate voices can assist the Heschl’s gyrus a little, leading to a greater ability for you to comprehend what your coworkers are saying in that loud restaurant.
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 lead to improved hearing outcomes. That way, you can concentrate a little less on straining to hear and a little more on enjoying yourself.