Selective hearing is a term that normally gets tossed about as a pejorative, an insult. When your mother used to accuse you of having “selective hearing,” she was suggesting that you listened to the part about going to the fair and (perhaps purposely) ignored the part about doing your chores.
But in reality it takes an incredible act of teamwork between your brain and your ears to have selective hearing.
Hearing in a Crowd
Perhaps you’ve encountered this situation before: you’ve had a long day at work, but your buddies all insist on meeting up for dinner. They pick the loudest restaurant (because it’s trendy and the food is delicious). And you strain and struggle to follow the conversation for over an hour and a half.
But it’s tough, and it’s taxing. And it’s a sign of hearing loss.
You think, perhaps the restaurant was simply too noisy. But no one else appeared to be struggling. The only one who appeared to be having trouble was you. Which gets you thinking: Why do ears with hearing impairment have such a hard time with the noise of a crowded room? It seems like hearing well in a crowded place is the first thing to go, but what’s the reason? Scientists have started to discover the solution, and it all begins with selective hearing.
How Does Selective Hearing Work?
The scientific term for what we’re loosely calling selective hearing is “hierarchical encoding,” and it doesn’t happen in your ears at all. This process almost completely takes place in your brain. At least, that’s in line with a new study done by a team at Columbia University.
Ears work just like a funnel as scientists have known for some time: they forward all of the unprocessed data that they collect to your brain. That’s where the real work occurs, particularly the auditory cortex. Vibrations triggered by moving air are interpreted by this part of the brain into recognizable sound information.
Precisely what these processes look like had remained a mystery despite the established understanding of the role played by the auditory cortex in the process of hearing. Scientists were able, by making use of unique research techniques on individuals with epilepsy, to get a better understanding of how the auditory cortex picks out voices in a crowd.
The Hearing Hierarchy
And here’s what these intrepid scientists found: most of the work done by the auditory cortex to pick out distinct voices is done by two separate parts. And in loud settings, they enable you to separate and boost particular voices.
- Superior temporal gyrus (STG): The differentiated voices go from the HG to the STG, and it’s at this point 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 determined by the STG..
- Heschl’s gyrus (HG): The first sorting stage is managed by this part of the auditory cortex. Heschl’s gyrus or HG breaks down each unique voice and separates them into discrete identities.
When you have hearing loss, your ears are lacking particular wavelengths so it’s more difficult for your brain to recognize voices (depending on your hearing loss it could be low or high frequencies). Your brain isn’t provided with enough information to assign separate identities to each voice. As a result, it all blends together (meaning interactions will harder to understand).
A New Algorithm From New Science
Hearing aids currently have features that make it easier to hear in loud environments. But now that we know what the fundamental process looks like, hearing aid makers can incorporate more of those natural functions into their device algorithms. For example, you will have a better ability to hear and understand what your coworkers are talking about with hearing aids that assist the Heshl’s gyrus and do a little more to identify voices.
Technology will get better at mimicking what takes place in nature as we discover more about how the brain really works in combination with the ears. And better hearing outcomes will be the outcome. That way, you can concentrate a little less on straining to hear and a little more on enjoying yourself.