Sometimes when an individual has a difficult time hearing, someone close to them insultingly says they have “selective hearing”. Perhaps you heard your mother suggest that your father had “selective hearing” when she suspected he might be ignoring her.
But actually 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 feels familiar: you’ve been through a long day at work, but your friends all insist on meeting up for dinner. 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, trying to follow the conversation.
But it’s very difficult and exhausting. And it’s an indication of hearing loss.
Maybe, you rationalize, the restaurant was just too loud. But no one else appeared to be having difficulties. It seemed like you were the only one having difficulty. Which gets you thinking: what is it about the crowded room, the cacophony of voices all battling to be heard, that throws hearing-impaired ears for a loop? Just why is it that being able to hear in a crowd is so quick to go? The solution, as reported by scientists, is selective hearing.
How Does Selective Hearing Function?
The term “selective hearing” is a process that doesn’t even take place in the ears and is scientifically known as “hierarchical encoding”. This process nearly entirely happens in your brain. At least, that’s in line with a new study performed by a team from Columbia University.
Ears work just like a funnel as scientists have known for quite a while: they deliver all of the raw data that they gather to your brain. That’s where the heavy lifting takes place, specifically the auditory cortex. Vibrations triggered by moving air are interpreted by this part of the brain into recognizable sound information.
Exactly what these processes look like had remained a mystery in spite of the existing 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 learn more about how the auditory cortex functions in relation to picking out voices in a crowd.
The Hearing Hierarchy
And the insight they found out are as follows: there are two parts of the auditory cortex that accomplish most of the work in allowing you to key in on distinct voices. They’re what allows you to sort and amplify specific voices in loud situations.
- Superior temporal gyrus (STG): The separated voices go from the HG to the STG, and it’s here that your brain begins to make some value determinations. The superior temporal gyrus determines which voices you want to give attention to and which can be safely moved to the background.
- Heschl’s gyrus (HG): The first sorting phase is managed by this region of the auditory cortex. Heschl’s gyrus or HG breaks down each unique voice and separates them into distinct identities.
When you have hearing problems, your ears are lacking particular wavelengths so it’s harder for your brain to differentiate voices (high or low, based upon your hearing loss). Your brain isn’t furnished with enough information to assign individual identities to each voice. As a result, it all blurs together (meaning interactions will more difficult to follow).
New Science = New Algorithm
Hearing aids already have features that make it less difficult to hear in noisy circumstances. But now that we understand what the basic process looks like, hearing aid makers can incorporate more of those natural operations into their instrument algorithms. As an 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 takes place in nature as we uncover more about how the brain works in conjunction with the ears. 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.