Sometimes when a person has a hard time hearing, somebody close to them insultingly suggests they have “selective hearing”. When your mother used to accuse you of having “selective hearing,” she meant that you paid attention to the part about chocolate cake for dessert and (maybe deliberately) ignored the bit about doing your chores.
But it turns out that selective hearing is quite the ability, an impressive linguistic accomplishment performed by cooperation between your ears and brain.
The Stress Of Trying to Hear in a Crowd
This situation probably seems familiar: you’re feeling burnt out from a long workday but your friends all really would like to go out for dinner and drinks. They choose the noisiest restaurant (because it’s popular and the food is the best in town). And you strain and struggle to follow the conversation for over an hour and a half.
But it’s challenging, and it’s taxing. This indicates that you could have hearing loss.
Perhaps, you rationalize, the restaurant was simply too noisy. But no one else appeared to be having difficulties. You seemed like the only one experiencing trouble. So you begin to ask yourself: Why do ears with hearing impairment have such a hard 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? Scientists have started to reveal the solution, 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 take place inside of your ears at all. The majority of this process occurs in the brain. At least, that’s as reported by a new study performed by a team from Columbia University.
Ears work just like a funnel which scientists have recognized for some time: they compile all the impulses and then deliver the raw data 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, interpreting impressions of moving air into perceptible sounds.
Because of significant research with MRI and CT scans, scientists have understood for years that the auditory cortex plays a considerable role in hearing, but they were clueless when it came to what those processes actually look like. Thanks to some unique research techniques concerning participants with epilepsy, scientists at Columbia were able to discover more about how the auditory cortex functions when it comes to picking out voices in a crowd.
The Hierarchy of Hearing
And the insight they found are as follows: there are two regions of the auditory cortex that perform most of the work in helping you key in on particular voices. And in loud settings, they enable you to separate and enhance certain voices.
- 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 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 manages the first stage of the sorting process. Heschl’s gyrus or HG breaks down each unique voice and separates them into distinct identities.
When you have hearing loss, your ears are lacking certain wavelengths so it’s more difficult for your brain to differentiate voices (high or low, based upon your hearing loss). Your brain can’t assign individual identities to each voice because it doesn’t have enough information. It all blurs together as a consequence (meaning interactions will more difficult to follow).
A New Algorithm From New Science
It’s typical for hearing aids to have features that make it less difficult to hear in a crowded situation. But hearing aid makers can now include more of those natural functions into their algorithms because they have a better idea of what the process looks like. As an example, hearing aids that do more to distinguish voices can help out the Heschl’s gyrus a little bit, resulting in a greater capacity for you to understand what your coworkers are saying in that loud restaurant.
Technology will get better at mimicking what happens in nature as we discover more about how the brain works in conjunction with the ears. 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.