Sometimes when a person has a difficult time hearing, somebody close to them insultingly suggests they have “selective hearing”. 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 (maybe intentionally) ignored the bit about cleaning your room.
But it turns out that selective hearing is quite the skill, an impressive linguistic accomplishment performed by teamwork between your brain and ears.
Hearing 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 decide on the loudest restaurant (because it’s trendy and the deep-fried cauliflower is the best in town). And you strain and struggle to follow the conversation for the entire evening.
But it’s tough, and it’s taxing. This indicates that you may have hearing loss.
Maybe, you rationalize, the restaurant was simply too loud. But no one else seemed to be struggling. The only one who appeared to be having trouble was you. Which makes you think: Why do ears with hearing impairment have such a hard time with the noise of a crowded room? Why is it that being able to hear in a crowd is so challenging? Scientists have started to discover the solution, and it all begins with selective hearing.
Selective Hearing – How Does it 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. This process almost exclusively occurs in your brain. At least, that’s according to a new study carried out by a team from Columbia University.
Ears work just like a funnel which scientists have understood for some time: they deliver all of the unprocessed data that they collect to your brain. In the auditory cortex the real work is then done. That’s the part of your gray matter that handles all those impulses, interpreting sensations of moving air into identifiable sounds.
Because of considerable research with MRI and CT scans, scientists have understood for years that the auditory cortex plays a crucial role in hearing, but they were clueless when it came to what those processes actually look like. Thanks to some novel research methods concerning participants with epilepsy, scientists at Columbia were able to find out more about how the auditory cortex functions in relation to picking out voices in a crowd.
The Hearing Hierarchy
And here’s what these intrepid scientists learned: the majority of the work done by the auditory cortex to isolate specific voices is performed by two different regions. And in loud environments, they enable you to isolate and amplify specific voices.
- Heschl’s gyrus (HG): The first sorting stage is taken care of by this part of the auditory cortex. Heschl’s gyrus or HG breaks down each unique voice and separates them into distinct identities.
- Superior temporal gyrus (STG): The separated voices move from the HG to the STG, and it’s at this point that your brain starts to make some value determinations. Which voices can be safely moved to the background and which ones you want to focused on is figured out by the STG..
When you start to suffer from hearing damage, it’s harder for your brain to identify voices because your ears are lacking certain wavelengths of sound (depending on your hearing loss it could be low or high frequencies). Your brain can’t assign separate identities to each voice because it doesn’t have enough information. It all blurs together as a consequence (which means discussions will more difficult to understand).
A New Algorithm From New Science
It’s typical for hearing aids to have functions that make it less difficult to hear in a crowd. But now that we understand what the basic process looks like, hearing aid makers can integrate more of those natural functions into their instrument algorithms. For example, you will have a better ability to hear and comprehend what your coworkers are saying with hearing aids that assist the Heshl’s gyrus and do a little more to identify voices.
The more we find out about how the brain works, particularly in connection with the ears, the better new technology will be capable of mimicking what takes place in nature. And that can result in improved hearing outcomes. That way, you can concentrate a little less on straining to hear and a little more on enjoying yourself.