Selective hearing is a phrase that commonly gets tossed about as a pejorative, an insult. When your mother used to accuse you of having “selective hearing,” she meant that you paid attention to the part about going to the fair and (maybe intentionally) disregarded the bit about doing your chores.
But in reality it takes an incredible act of cooperation between your brain and your ears to have selective hearing.
The Difficulty Of Trying to Hear in a Crowd
Perhaps you’ve dealt with this situation before: you’re feeling burnt out from a long day at work but your friends all really would like to go out for dinner and drinks. They choose the loudest restaurant (because it’s trendy and the food is delicious). And you strain and struggle to understand the conversation for the entire evening.
But it’s challenging, and it’s taxing. This indicates that you could have hearing loss.
Perhaps, you rationalize, the restaurant was just too noisy. But no one else appeared to be struggling. The only person who appeared to be having difficulty was you. Which makes you think: what is it about the crowded room, the cacophony of voices all struggling to be heard, that throws hearing-impaired ears for a loop? Why is it that being able to hear in a crowd is so quick to go? Scientists have started to reveal the solution, and it all starts with selective hearing.
Selective Hearing – How Does it Work?
The phrase “selective hearing” is a task that doesn’t even happen in the ears and is technically called “hierarchical encoding”. This process almost exclusively takes place in your brain. At least, that’s as reported by a new study done by a team from Columbia University.
Scientists have known for quite some time that human ears essentially work as a funnel: they deliver all of the unprocessed data that they gather to your brain. That’s where the real work occurs, specifically the auditory cortex. That’s the part of your gray matter that processes all those impulses, interpreting sensations of moving air into recognizable 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 clueless regarding what those processes really look like. Thanks to some unique research techniques concerning participants with epilepsy, scientists at Columbia were able to find out more about how the auditory cortex functions in relation to discerning voices in a crowd.
The Hierarchy of Hearing
And here’s what these intrepid scientists discovered: the majority of the work performed by the auditory cortex to isolate particular voices is performed by two separate regions. They’re what allows you to separate and enhance distinct voices in loud environments.
- Heschl’s gyrus (HG): The first sorting stage is managed by this part of the auditory cortex. Heschl’s gyrus or HG breaks down each unique voice and separates them into discrete identities.
- Superior temporal gyrus (STG): Eventually your brain will need to make some value based decisions and this is done in the STG once it receives the voices that were previously differentiated by the HG. The superior temporal gyrus figures out which voices you want to give attention to and which can be safely moved to the background.
When you start to suffer with hearing impairment, it’s harder for your brain to distinguish voices because your ears are lacking particular wavelengths of sound (depending on your hearing loss it might be low or high frequencies). Your brain can’t assign individual identities to each voice because it doesn’t have enough data. It all blends together as a result (which makes discussions tough to follow).
A New Algorithm From New Science
Hearing aids already have features that make it easier to hear in loud situations. But now that we understand what the fundamental process looks like, hearing aid manufacturers can incorporate more of those natural operations into their device algorithms. As an example, hearing aids that do more to identify voices can help out the Heschl’s gyrus a little, resulting in a greater ability for you to comprehend what your coworkers are talking about in that loud restaurant.
Technology will get better at mimicking what takes place in nature as we discover more about how the brain functions in conjunction with the ears. And that can result in better hearing outcomes. Then you can focus a little more on enjoying yourself and a little less on straining to hear.