Selective hearing is a phrase 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 (maybe intentionally) ignored the part about doing your chores.
But in reality it takes an amazing act of cooperation between your ears and your brain to have selective hearing.
The Difficulty Of Trying to Hear in a Crowd
This scenario potentially seems familiar: 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. They choose the noisiest restaurant (because they have great food and live entertainment). And you strain and struggle to understand the conversation for the entire evening.
But it’s very difficult and exhausting. This suggests that you could have hearing loss.
You think, perhaps the restaurant was just too noisy. But… everyone else appeared to be having a great time. You seemed like the only one experiencing 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? Just why is it that being able to hear in a crowd is so challenging? The solution, according to scientists, is selective hearing.
How Does Selective Hearing Work?
The phrase “selective hearing” is a task that doesn’t even happen in the ears and is formally known as “hierarchical encoding”. The majority of this process occurs in the brain. At least, that’s in accordance with a new study done by a team at Columbia University.
Ears work like a funnel which scientists have known for quite a while: they gather all the signals and then deliver the raw data to your brain. In the auditory cortex the real work is then done. That’s the part of your gray matter that handles all those impulses, interpreting sensations of moving air into identifiable sounds.
Precisely what these processes look like was still unknown despite the existing knowledge of the role played by the auditory cortex in the hearing process. Thanks to some unique research methods involving participants with epilepsy, scientists at Columbia were able to discover more about how the auditory cortex functions in relation to discerning voices in a crowd.
The Hearing Hierarchy
And here is what these intrepid scientists found: 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 situations, they allow you to isolate and enhance specific voices.
- Superior temporal gyrus (STG): Sooner or later your brain will need to make some value based decisions and this occurs in the STG once it receives the voices which were previously differentiated by the HG. Which voices can be freely moved to the background and which ones you want to focused on is figured out by the STG..
- Heschl’s gyrus (HG): This is the part of the auditory cortex that handles the first phase of the sorting routine. Researchers observed that the Heschl’s gyrus (we’re just going to call it HG from now on) was processing each distinct voice, separating them via individual identities.
When you have hearing impairment, your ears are lacking certain wavelengths so it’s more difficult for your brain to recognize voices (high or low, depending on your hearing loss). Your brain isn’t furnished with enough data to assign individual identities to each voice. As a result, it all blends together (which means interactions will more difficult to follow).
New Science = New Algorithm
Hearing aids already have features that make it easier to hear in loud environments. But hearing aid makers can now integrate more of those natural functions into their algorithms because they have a better idea of what the process looks like. For instance, you will have a better capacity to hear and comprehend what your coworkers are talking about with hearing aids that assist the Heshl’s gyrus and do a little more to differentiate voices.
The more we understand about how the brain works, specifically in connection with the ears, the better new technology will be capable of mimicking what happens in nature. And that can lead to improved hearing success. That way, you can concentrate a little less on straining to hear and a little more on enjoying yourself.