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 was suggesting that you paid attention to the part about going to the fair and (maybe intentionally) ignored the bit 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
Maybe you’ve encountered this scenario before: you’re feeling tired from a long workday but your friends all really want to go out for dinner and drinks. And naturally, they want to go to the noisiest restaurant (because they have amazing food and live entertainment). And you spend an hour and a half straining your ears, working hard to follow the conversation.
But it’s very difficult and exhausting. This suggests that you might have hearing loss.
Maybe, you rationalize, the restaurant was simply too noisy. But no one else appeared to be having difficulties. It seemed like you were the only one having trouble. Which makes you think: Why do ears with hearing impairment have such a difficult time with the noise of a crowded room? Why is it that being able to hear in a crowd is so challenging? The solution, as reported by scientists, is selective hearing.
How Does Selective Hearing Work?
The scientific term for what we’re broadly calling selective hearing is “hierarchical encoding,” and it doesn’t happen in your ears at all. This process nearly completely happens in your brain. At least, that’s according to a new study carried out by a team from Columbia University.
Scientists have recognized for quite a while that human ears effectively work as a funnel: they forward all of the raw data that they gather to your brain. That’s where the real work happens, specifically the auditory cortex. That’s the part of your brain that processes all those signals, interpreting sensations of moving air into perceptible sounds.
Exactly what these processes look like was still unknown in spite of the established knowledge of the role played by the auditory cortex in the hearing process. Thanks to some unique research methods including participants with epilepsy, scientists at Columbia were able to discover more about how the auditory cortex functions in relation to picking out voices in a crowd.
The Hearing Hierarchy
And the information they found out follows: there are two components of the auditory cortex that perform most of the work in helping you identify particular voices. And in loud environments, they allow you to separate and intensify particular voices.
- Heschl’s gyrus (HG): The first sorting phase is handled by this region of the auditory cortex. Heschl’s gyrus or HG processes each individual voice and separates them into distinguishable identities.
- Superior temporal gyrus (STG): Eventually your brain needs to make some value based choices and this occurs in the STG once it receives the voices that were previously differentiated by the HG. Which voices can be safely moved to the background and which ones you want to focused on is determined by the STG..
When you have hearing problems, your ears are lacking specific wavelengths so it’s more difficult for your brain to recognize voices (depending on your hearing loss it might be high or low frequencies). Your brain isn’t given enough data to assign separate identities to each voice. It all blends together as a result (which makes conversations tough to follow).
A New Algorithm From New Science
It’s common for hearing aids to come with features that make it less difficult to hear in a crowded situation. But now that we know what the basic process looks like, hearing aid companies can incorporate more of those natural operations into their device algorithms. For instance, you will have a better 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 identify voices.
Technology will get better at mimicking what happens in nature as we uncover more about how the brain really works in combination with the ears. And that can lead to improved hearing success. That way, you can focus a little less on straining to hear and a little more on enjoying yourself.