Selective hearing is a term that frequently gets tossed about as a pejorative, an insult. Perhaps you heard your mother suggest that your father had “selective hearing” when she believed he might be ignoring her.
But in reality it takes an amazing act of cooperation between your ears and your brain to have selective hearing.
The Stress Of Trying to Hear in a Crowd
This scenario potentially seems familiar: you’ve been through a long day at work, but your buddies all insist on going out to dinner. They choose the loudest restaurant (because they have incredible food and live entertainment). And you spend an hour and a half straining your ears, trying to follow the conversation.
But it’s very difficult and exhausting. This indicates that you might have hearing loss.
Maybe, you rationalize, the restaurant was simply too noisy. But no one else appeared to be struggling. You seemed like the only one experiencing trouble. Which makes you think: what is it about the crowded room, the cacophony of voices all battling to be heard, that throws hearing-impaired ears for a loop? It seems as if hearing well in a crowd is the first thing to go, but why? Scientists have begun to reveal the solution, and it all begins with selective hearing.
Selective Hearing – How Does it Work?
The phrase “selective hearing” is a task that doesn’t even occur in the ears and is technically called “hierarchical encoding”. This process nearly completely occurs in your brain. At least, that’s as reported by a new study carried out by a team from Columbia University.
Ears work like a funnel which scientists have understood for quite a while: they deliver all of the unprocessed data that they collect to your brain. That’s where the heavy lifting happens, particularly the auditory cortex. That’s the part of your brain that processes all those impulses, translating sensations of moving air into recognizable sounds.
Because of substantial research with CT and MRI scans, scientists have understood for years that the auditory cortex plays a substantial role in hearing, but they were clueless when it came to what those processes actually look like. Scientists were able, by using novel research techniques on individuals with epilepsy, to get a better understanding of how the auditory cortex discerns voices in a crowd.
The Hearing Hierarchy
And here is what these intrepid scientists found out: there are two regions of the auditory cortex that perform most of the work in helping you identify specific voices. They’re what enables you to separate and intensify specific voices in noisy situations.
- Superior temporal gyrus (STG): Sooner or later your brain needs to make some value based decisions and this occurs in the STG once it receives the voices that were previously separated by the HG. The superior temporal gyrus figures out which voices you want to pay attention to and which can be confidently moved to the background.
- Heschl’s gyrus (HG): This is the region of the auditory cortex that takes care of the first phase of the sorting process. Scientists discovered that the Heschl’s gyrus (we’re just going to call it HG from here on out) was breaking down each individual voice, classifying them via individual identities.
When you begin to suffer with hearing problems, it’s more difficult for your brain to identify voices because your ears are missing specific wavelengths of sound (low or high, depending on your hearing loss). Your brain isn’t supplied with enough information to assign individual identities to each voice. It all blurs together as a result (meaning interactions will harder to understand).
A New Algorithm From New Science
It’s standard for hearing aids to come with features that make it easier to hear in a crowded situation. But hearing aid manufacturers can now incorporate more of those natural functions into their algorithms because they have a better idea of what the process looks like. As an example, hearing aids that do more to identify voices can assist the Heschl’s gyrus a little bit, bringing about a greater capacity for you to understand what your coworkers are saying in that noisy restaurant.
The more we find out about how the brain works, specifically in combination with the ears, the better new technology will be able to mimic what happens in nature. And that can result in improved hearing success. Then you can concentrate a little more on enjoying yourself and a little less on straining to hear.