Selective hearing is a phrase that commonly gets tossed about as a pejorative, an insult. Maybe you heard your mother accuse your father of having “selective hearing” when she thought he might be ignoring her.
But actually selective hearing is quite the ability, an amazing linguistic feat executed by cooperation between your brain and ears.
Hearing in a Crowd
Perhaps you’ve experienced this scenario before: you’re feeling tired from a long workday but your friends all really want to go out for dinner and drinks. They choose the loudest restaurant (because they have amazing food and live entertainment). And you strain and struggle to follow the conversation for the entire evening.
But it’s challenging, and it’s taxing. This suggests that you may have hearing loss.
Perhaps, you rationalize, the restaurant was simply too loud. But no one else appeared to be struggling. The only one who appeared to be having difficulty was you. Which makes you think: Why do ears that have hearing impairment have such a difficult time with the noise of a crowded room? Just why is it that being able to hear in a crowd is so challenging? Scientists have begun to reveal the solution, and it all begins with selective hearing.
How Does Selective Hearing Work?
The scientific name for what we’re loosely calling selective hearing is “hierarchical encoding,” and it doesn’t happen inside of your ears at all. The majority of this process happens in the brain. At least, that’s in line with a new study done by a team at Columbia University.
Scientists have recognized for quite some time that human ears basically work like a funnel: they collect all the signals and then forward the raw data to your brain. That’s where the real work happens, particularly the auditory cortex. That’s the part of your gray matter that processes all those signals, interpreting impressions of moving air into identifiable sounds.
Because of comprehensive research with CT and MRI scans, scientists have understood for years that the auditory cortex plays a considerable role in hearing, but they were stumped regarding what those processes actually look like. Scientists were able, by utilizing unique research techniques on people with epilepsy, to get a better understanding of how the auditory cortex discerns voices in a crowd.
The Hierarchy of Hearing
And here’s what these intrepid scientists found: most of the work performed by the auditory cortex to pick out distinct voices is performed by two separate parts. They’re what allows you to separate and intensify particular voices in noisy situations.
- Superior temporal gyrus (STG): At some point your brain needs to make some value based decisions and this occurs in the STG once it receives the voices which were previously differentiated by the HG. The superior temporal gyrus figures out which voices you want to give attention to and which can be securely moved to the background.
- Heschl’s gyrus (HG): This is the region of the auditory cortex that manages the first stage of the sorting process. Researchers discovered that the Heschl’s gyrus (we’re simply going to call it HG from now on) was breaking down each distinct voice, separating them via individual identities.
When you begin to suffer with hearing impairment, it’s more difficult for your brain to identify voices because your ears are missing certain wavelengths of sound (depending on your hearing loss it might be low or high frequencies). Your brain isn’t supplied with enough data to assign individual identities to each voice. It all blurs together as a consequence (meaning interactions will more difficult to understand).
A New Algorithm From New Science
It’s common 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 manufacturers can incorporate more of those natural functions into their device algorithms. For example, hearing aids that do more to identify voices can help out the Heschl’s gyrus a little, bringing about a greater capacity for you to comprehend what your coworkers are talking about in that noisy restaurant.
The more we learn about how the brain works, especially in connection with the ears, the better new technology will be able to mimic what takes place in nature. And better hearing success will be the outcome. That way, you can concentrate a little less on straining to hear and a little more on enjoying yourself.
