Selective hearing is a term that commonly gets tossed about as a pejorative, an insult. When your mother used to accuse you of having “selective hearing,” she meant that you listened to the part about going to the fair and (perhaps purposely) ignored the bit about doing your chores.
But it turns out that selective hearing is quite the ability, an impressive linguistic accomplishment executed by cooperation between your brain and ears.
Hearing in a Crowd
Maybe you’ve dealt with this situation before: 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 of course, they want to go to the noisiest restaurant (because they have great food and live entertainment). And you spend an hour and a half straining your ears, trying to follow the conversation.
But it’s very difficult and exhausting. And it’s a sign of hearing loss.
You think, perhaps the restaurant was just too noisy. But… everyone else appeared to be having a fine go of it. It seemed like you were the only one having difficulty. So you start to ask yourself: Why do ears with hearing impairment have such a hard time with the noise of a packed room? Why is it that being able to hear in a crowd is so challenging? The answer, according to scientists, is selective hearing.
How Does Selective Hearing Work?
The term “selective hearing” is a process that doesn’t even occur in the ears and is formally known as “hierarchical encoding”. This process nearly exclusively occurs in your brain. At least, that’s in line with a new study carried out by a team at Columbia University.
Ears work just like a funnel which scientists have recognized for some time: they compile all the signals and then send the raw data to your brain. That’s where the real work occurs, particularly the auditory cortex. Vibrations caused 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 existing understanding of the role played by the auditory cortex in the hearing process. Thanks to some innovative research methods concerning participants with epilepsy, scientists at Columbia were able to find out more about how the auditory cortex functions in terms of discerning voices in a crowd.
The Hearing Hierarchy
And here’s what these intrepid scientists discovered: there are two components of the auditory cortex that accomplish most of the work in allowing you to identify individual voices. And in loud situations, they enable you to isolate and amplify specific voices.
- Heschl’s gyrus (HG): The first sorting phase is managed by this region of the auditory cortex. Scientists discovered that the Heschl’s gyrus (we’re just going to call it HG from now on) was processing each unique voice, separating them into unique identities.
- 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 determinations. The superior temporal gyrus figures out which voices you want to focus on and which can be safely moved to the background.
When you have hearing loss, your ears are missing specific wavelengths so it’s harder for your brain to distinguish voices (low or high, based upon your hearing loss). Your brain can’t assign separate identities to each voice because it doesn’t have enough data. As a result, it all blurs together (which means conversations will harder to understand).
A New Algorithm From New Science
It’s standard for hearing aids to have functions that make it easier to hear in a crowded situation. But hearing aid makers can now incorporate more of those natural functions into their algorithms because they have a better idea of what the process looks like. For instance, hearing aids that do more to differentiate voices can assist the Heschl’s gyrus a little, resulting in a greater ability for you to understand 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 functions in combination with the ears. And that can lead to better hearing success. That way, you can concentrate a little less on struggling to hear and a little more on enjoying yourself.