Sometimes when an individual has a difficult time hearing, someone close to them insultingly says they have “selective hearing”. Maybe you heard your mother accuse your father of having “selective hearing” when she believed he might be ignoring her.
But it turns out that selective hearing is quite the skill, an impressive linguistic feat conducted by teamwork between your brain and ears.
The Stress Of Trying to Hear in a Crowd
This scenario probably feels familiar: you’re feeling tired from a long day at work but your friends all really would like to go out for dinner and drinks. They decide on the noisiest restaurant (because they have incredible food and live entertainment). And you strain and struggle to understand the conversation for the entire evening.
But it’s very difficult and exhausting. And it’s a sign of hearing loss.
You think, maybe the restaurant was simply too loud. But… everyone else appeared to be having a fine go of it. The only one who appeared to be having trouble was you. So you start to wonder: Why do ears with hearing impairment have such a hard time with the noise of a packed 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.
How Does Selective Hearing Operate?
The phrase “selective hearing” is a task that doesn’t even occur in the ears and is technically known as “hierarchical encoding”. Most of this process occurs in the brain. At least, that’s in line with a new study carried out by a team from Columbia University.
Ears work just like a funnel which scientists have understood for quite a while: they send all of the raw data that they gather to your brain. That’s where the heavy lifting takes place, particularly the auditory cortex. Vibrations triggered by moving air are interpreted by this part of the brain into recognizable sound information.
Because of comprehensive research with CT and MRI scans, scientists have known for years that the auditory cortex plays a substantial role in hearing, but they were stumped with regards to what those processes actually look like. Thanks to some novel research techniques involving 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: the majority of the work done by the auditory cortex to isolate specific voices is done by two different parts. And in noisy conditions, they enable you to separate and boost specific voices.
- Heschl’s gyrus (HG): This is the part of the auditory cortex that takes care of the first stage of the sorting process. Scientists observed that the Heschl’s gyrus (we’re simply going to call it HG from here on out) was breaking down each distinct voice, classifying them via individual identities.
- Superior temporal gyrus (STG): At some point your brain needs to make some value based choices and this happens in the STG after it receives the voices that were previously differentiated by the HG. The superior temporal gyrus determines which voices you want to focus on and which can be safely moved to the background.
When you have hearing impairment, your ears are missing certain wavelengths so it’s harder for your brain to differentiate voices (high or low, depending on your hearing loss). Your brain can’t assign individual identities to each voice because it doesn’t have enough data. It all blends together as a consequence (which makes interactions difficult to follow).
New Science = New Algorithm
It’s standard for hearing aids to have features that make it easier to hear in a crowded situation. But now that we understand what the fundamental process looks like, hearing aid companies can integrate more of those natural operations into their device algorithms. As an example, you will have a better ability to hear and comprehend what your coworkers are saying with hearing aids that assist the Heshl’s gyrus and do a little more to distinguish voices.
The more we understand about how the brain works, especially in conjunction with the ears, the better new technology will be capable of mimicking what happens in nature. And better hearing outcomes will be the result. Then you can focus a little more on enjoying yourself and a little less on straining to hear.