Selective hearing is a phrase that usually is used 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 intentionally) ignored the part about cleaning your room.
But it turns out that selective hearing is quite the ability, an amazing linguistic feat conducted by teamwork between your ears and brain.
The Difficulty Of Trying to Hear in a Crowd
This situation probably feels familiar: you’ve had a long day at work, but your buddies all insist on going out to dinner. They decide on the noisiest restaurant (because it’s popular and the deep-fried cauliflower is delicious). And you spend the entire evening straining your ears, working hard to follow the conversation.
But it’s challenging, and it’s taxing. This indicates that you may have hearing loss.
You think, perhaps the restaurant was just too loud. But… everyone else appeared to be having a fine go of it. The only person who appeared to be having trouble was you. Which gets you thinking: Why do ears with hearing impairment have such a difficult time with the noise of a packed room? It seems as if hearing well in a crowded place is the first thing to go, but why? The answer, as reported by scientists, is selective hearing.
Selective Hearing – How Does it Work?
The term “selective hearing” is a task that doesn’t even occur in the ears and is technically known as “hierarchical encoding”. Most of this process occurs in the brain. At least, that’s in accordance with a new study carried out by a team from Columbia University.
Scientists have recognized for some time that human ears effectively work like a funnel: they gather all the signals and then forward the raw information to your brain. In the auditory cortex the real work is then accomplished. That’s the part of your gray matter that processes all those impulses, translating sensations of moving air into perceptible sounds.
Precisely what these processes look like was still unknown despite the established understanding of the role played by the auditory cortex in the process of hearing. Scientists were able, by using novel research techniques on people with epilepsy, to get a better picture of how the auditory cortex discerns voices in a crowd.
The Hierarchy of Hearing
And the insight they discovered are as follows: there are two regions of the auditory cortex that do most of the work in allowing you to key in on particular voices. They’re what enables you to separate and enhance specific voices in noisy settings.
- Heschl’s gyrus (HG): This is the region of the auditory cortex that manages the first stage of the sorting process. Heschl’s gyrus or HG processes each unique voice and separates them into distinguishable identities.
- Superior temporal gyrus (STG): The differentiated voices go from the HG to the STG, and it’s here that your brain starts to make some value distinctions. The superior temporal gyrus figures out which voices you want to give attention to and which can be confidently moved to the background.
When you have hearing impairment, your ears are lacking particular wavelengths so it’s harder for your brain to distinguish voices (depending on your hearing loss it might be high or low frequencies). Your brain can’t assign separate identities to each voice because it doesn’t have enough data. Consequently, it all blurs together (meaning conversations will harder to understand).
A New Algorithm From New Science
Hearing aids already have functions that make it easier to hear in noisy environments. But hearing aid makers can now incorporate more of those natural functions into their algorithms because they have a greater idea of what the process looks like. For instance, you will have a better ability 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 separate voices.
The more we understand about how the brain works, particularly in conjunction with the ears, the better new technology will be able to mimic what happens in nature. And better hearing outcomes will be the outcome. Then you can focus a little more on enjoying yourself and a little less on straining to hear.