Selective hearing is a term that usually is used 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 chocolate cake for dessert and (maybe deliberately) ignored the part about doing your chores.
But actually selective hearing is quite the skill, an impressive linguistic feat executed by teamwork between your ears and brain.
The Difficulty Of Trying to Hear in a Crowd
Perhaps you’ve encountered this scenario 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. And of course, they want to go to the noisiest restaurant (because they have incredible food and live entertainment). And you strain and struggle to understand the conversation for over an hour and a half.
But it’s difficult, and it’s taxing. And it’s an indication of hearing loss.
You think, maybe the restaurant was just too noisy. But… everyone else appeared to be having a great time. You seemed like the only one experiencing difficulty. So you start to wonder: what is it about the packed room, the cacophony of voices all battling 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 begun to uncover the answer, and it all begins with selective hearing.
Selective Hearing – How Does it Work?
The scientific name for what we’re broadly calling selective hearing is “hierarchical encoding,” and it doesn’t take place in your ears at all. This process almost completely takes place in your brain. At least, that’s as reported by a new study carried out by a team at Columbia University.
Scientists have known for quite some time that human ears effectively work as a funnel: they gather all the signals and then send the raw information to your brain. In the auditory cortex the real work is then done. Vibrations caused by moving air are translated by this portion of the brain into recognizable sound information.
Because of extensive 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 with regards to what those processes actually look like. Thanks to some innovative research methods involving participants with epilepsy, scientists at Columbia were able to learn more about how the auditory cortex functions in terms of picking out voices in a crowd.
The Hierarchy of Hearing
And the information they found follows: there are two components of the auditory cortex that accomplish most of the work in helping you identify particular voices. And in loud situations, they enable you to isolate and enhance particular voices.
- Heschl’s gyrus (HG): This is the part of the auditory cortex that handles the first phase of the sorting process. Heschl’s gyrus or HG processes each individual voice and separates them into distinguishable identities.
- Superior temporal gyrus (STG): The differentiated voices go from the HG to the STG, and it’s at this point that your brain starts to make some value distinctions. Which voices can be freely moved to the background and which ones you want to focused on is determined by the STG..
When you start to suffer from hearing damage, it’s more difficult for your brain to identify voices because your ears are lacking certain wavelengths of sound (high or low, based upon your hearing loss). Your brain isn’t provided with enough data to assign separate identities to each voice. It all blurs together as a consequence (which makes conversations difficult to follow).
A New Algorithm From New Science
Hearing aids currently have features that make it easier to hear in loud environments. But hearing aid manufacturers can now integrate more of those natural functions into their algorithms because they have a better idea of what the process looks like. For instance, 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 separate voices.
The more we learn about how the brain works, specifically in conjunction with the ears, the better new technology will be able to mimic what happens in nature. And that can lead to improved hearing success. That way, you can focus a little less on straining to hear and a little more on enjoying yourself.