Selective hearing is a term that usually is used 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 deliberately) disregarded the part about cleaning your room.
But it turns out that selective hearing is quite the skill, an amazing linguistic feat conducted by cooperation between your brain and ears.
The Stress Of Trying to Hear in a Crowd
This situation potentially feels familiar: you’re feeling tired from a long day at work but your friends all really want to go out for dinner and drinks. And of course, they want to go to the loudest restaurant (because it’s popular and the food is the best in town). And you spend an hour and a half straining your ears, attempting to follow the conversation.
But it’s very difficult and exhausting. This indicates that you might have hearing loss.
You think, maybe the restaurant was just too noisy. But… everyone else appeared to be having a fine go of it. You seemed like the only one experiencing difficulty. So you begin to wonder: Why do ears that have hearing impairment have such a difficult time with the noise of a crowded room? It seems like hearing well in a crowd is the first thing to go, but what’s the reason? Scientists have begun to discover the answer, and it all begins with selective hearing.
How Does Selective Hearing Function?
The scientific term for what we’re loosely calling selective hearing is “hierarchical encoding,” and it doesn’t take place in your ears at all. Most of this process occurs in the brain. At least, that’s as reported by a new study done by a team from Columbia University.
Ears work like a funnel which scientists have recognized for quite a while: they forward all of the unprocessed data that they collect to your brain. In the auditory cortex the real work is then done. Vibrations triggered by moving air are interpreted by this part of the brain into perceptible sound information.
Precisely what these processes look like was still unknown in spite of the existing knowledge of the role played by the auditory cortex in the process of hearing. Thanks to some unique research techniques including participants with epilepsy, scientists at Columbia were able to learn more about how the auditory cortex works in relation to discerning voices in a crowd.
The Hearing Hierarchy
And the information they discovered are as follows: there are two regions of the auditory cortex that manage most of the work in allowing you to identify specific voices. And in noisy situations, they enable you to separate and enhance certain voices.
- Heschl’s gyrus (HG): This is the part of the auditory cortex that handles the first stage of the sorting process. Scientists discovered that the Heschl’s gyrus (we’re simply going to call it HG from here on out) was breaking down each distinct voice, separating them into unique identities.
- Superior temporal gyrus (STG): The separated voices move from the HG to the STG, and it’s here that your brain begins to make some value distinctions. 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 lacking specific wavelengths so it’s more difficult for your brain to distinguish voices (depending on your hearing loss it could be low or high frequencies). Your brain isn’t provided with enough data to assign separate identities to each voice. Consequently, it all blurs together (which makes conversations tough 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 crowd. But now that we know what the basic process looks like, hearing aid companies can integrate more of those natural operations into their instrument algorithms. For example, you will have a better capacity to hear and understand what your coworkers are talking about with hearing aids that help the Heshl’s gyrus and do a little more to distinguish 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 better hearing outcomes will be the outcome. That way, you can concentrate a little less on struggling to hear and a little more on enjoying yourself.