Selective hearing is a term that commonly is used as a pejorative, an insult. Perhaps you heard your mother accuse your father of having “selective hearing” when she suspected he was ignoring her.
But in reality it takes an incredible act of teamwork between your ears and your brain to have selective hearing.
The Difficulty Of Trying to Hear in a Crowd
Maybe you’ve dealt with this situation before: you’re feeling burnt out from a long workday but your friends all really want to go out for dinner and drinks. They choose the loudest restaurant (because it’s popular and the deep-fried cauliflower is the best in town). And you strain and struggle to follow the conversation for the entire evening.
But it’s challenging, 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 seemed to be having difficulties. The only person who appeared to be having difficulty was you. Which gets you thinking: Why do ears that have hearing impairment have such a hard time with the noise of a crowded room? It seems as if hearing well in a crowd is the first thing to go, but why? The solution, according to scientists, is selective hearing.
Selective Hearing – How Does it Work?
The phrase “selective hearing” is a task that doesn’t even take place in the ears and is formally known as “hierarchical encoding”. This process almost entirely happens in your brain. At least, that’s in accordance with a new study carried out by a team from Columbia University.
Ears work like a funnel which scientists have understood for some time: they gather all the signals and then deliver the raw data to your brain. In the auditory cortex the real work is then done. Vibrations caused by moving air are translated by this portion of the brain into perceptible sound information.
Because of comprehensive research with CT and MRI scans, scientists have known for years that the auditory cortex plays a considerable role in hearing, but they were stumped regarding what those processes actually look like. Thanks to some novel research techniques including participants with epilepsy, scientists at Columbia were able to learn more about how the auditory cortex works in relation to discerning voices in a crowd.
The Hearing Hierarchy
And the facts they found are as follows: there are two components of the auditory cortex that do most of the work in allowing you to identify individual voices. They’re what allows you to sort and amplify distinct voices in noisy environments.
- Superior temporal gyrus (STG): At some point your brain needs to make some value based decisions and this is done in the STG after it receives the voices that were previously separated by the HG. The superior temporal gyrus figures out which voices you want to pay attention to and which can be securely moved to the background.
- Heschl’s gyrus (HG): This is the region of the auditory cortex that takes care of the first phase of the sorting routine. Heschl’s gyrus or HG breaks down each individual voice and separates them into discrete identities.
When you have hearing impairment, your ears are lacking specific wavelengths so it’s harder for your brain to differentiate voices (depending on your hearing loss it could be low or high frequencies). Your brain isn’t supplied with enough data to assign separate identities to each voice. It all blurs together as a result (which makes interactions difficult to follow).
New Science = New Algorithm
It’s typical for hearing aids to come with features that make it easier to hear in a crowd. But hearing aid makers can now incorporate more of those natural functions into their algorithms because they have a better concept of what the process looks like. For instance, you will have a greater ability to hear and understand 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 connection with the ears, the better new technology will be able to mimic 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.