Selective hearing is a term that normally is used as a pejorative, an insult. When your mother used to accuse you of having “selective hearing,” she was suggesting that you listened to the part about going to the fair and (maybe deliberately) disregarded the part about doing your chores.
But actually selective hearing is quite the talent, an amazing linguistic accomplishment carried out by teamwork between your ears and brain.
The Difficulty Of Trying to Hear in a Crowd
Perhaps you’ve dealt with this situation before: you’ve had a long day at work, but your buddies all insist on going out to dinner. They decide on the loudest restaurant (because they have incredible food and live entertainment). And you strain and struggle to understand the conversation for the entire evening.
But it’s very difficult and exhausting. This suggests that you could have hearing loss.
Maybe, you rationalize, the restaurant was just too loud. But… everyone else appeared to be having a fine go of it. The only one who appeared to be having difficulty was you. Which makes you think: what is it about the packed room, the cacophony of voices all trying to be heard, that causes hearing impaired ears to struggle? Just why is it that being able to hear in a crowd is so challenging? The answer, as reported by scientists, is 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 inside of your ears at all. The majority of this process occurs in the brain. At least, that’s in line with a new study done by a team from Columbia University.
Scientists have recognized for some time that human ears basically work as a funnel: they forward all of the raw data that they gather 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 comprehensive research with CT and MRI scans, scientists have recognized 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. Thanks to some novel research techniques concerning participants with epilepsy, scientists at Columbia were able to find out more about how the auditory cortex functions when it comes to picking out voices in a crowd.
The Hierarchy of Hearing
And here is what these intrepid scientists learned: there are two components of the auditory cortex that accomplish most of the work in helping you key in on specific voices. And in loud situations, they allow you to isolate and boost specific voices.
- Superior temporal gyrus (STG): The separated voices go from the HG to the STG, and it’s here that your brain starts to make some value distinctions. The superior temporal gyrus figures out which voices you want to pay attention to and which can be securely moved to the background.
- Heschl’s gyrus (HG): This is the region of the auditory cortex that manages the first stage of the sorting routine. Scientists discovered that the Heschl’s gyrus (we’re just going to call it HG from here on out) was processing each unique voice, separating them into individual identities.
When you have hearing problems, your ears are missing particular wavelengths so it’s more difficult for your brain to recognize voices (high or low, based upon your hearing loss). Your brain isn’t given enough information to assign separate identities to each voice. It all blends together as a result (which makes interactions hard to follow).
New Science = New Algorithm
Hearing aids already have functions that make it easier to hear in loud settings. But now that we know what the fundamental process looks like, hearing aid manufacturers can integrate more of those natural operations into their instrument algorithms. For instance, you will have a better ability to hear and understand what your coworkers are saying with hearing aids that help the Heshl’s gyrus and do a little more to identify voices.
The more we discover about how the brain works, especially in conjunction with the ears, the better new technology will be able to mimic what happens in nature. And better hearing outcomes will be the outcome. Then you can focus a little more on enjoying yourself and a little less on straining to hear.