Selective hearing is a phrase that frequently gets tossed about 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 chocolate cake for dessert and (maybe deliberately) ignored the part about doing your chores.
But in reality it takes an incredible act of teamwork between your brain and your ears to have selective hearing.
Hearing in a Crowd
This scenario probably feels familiar: you’re feeling burnt out from a long day at work but your friends all really want to go out for dinner and drinks. They pick the loudest restaurant (because they have great food and live entertainment). And you spend the entire evening straining your ears, trying to follow the conversation.
But it’s challenging, and it’s taxing. This suggests that you might have hearing loss.
You think, perhaps the restaurant was simply too noisy. But… everyone else appeared to be having a great time. It seemed like you were the only one experiencing difficulty. 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? Just 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 phrase “selective hearing” is a process that doesn’t even occur in the ears and is formally called “hierarchical encoding”. Most of this process happens in the brain. At least, that’s according to a new study carried out by a team at Columbia University.
Scientists have known for some time that human ears essentially work like a funnel: they gather all the signals and then forward the raw data to your brain. In the auditory cortex the real work is then done. Vibrations triggered by moving air are translated by this part of the brain into recognizable sound information.
Exactly what these processes look like was still unknown despite the existing understanding of the role played by the auditory cortex in the process of hearing. 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 in relation to picking out voices in a crowd.
The Hierarchy of Hearing
And here is what these intrepid scientists found: the majority of the work done by the auditory cortex to pick out particular voices is accomplished by two separate regions. And in loud situations, they allow you to isolate and intensify specific voices.
- Superior temporal gyrus (STG): Eventually your brain needs to make some value based decisions and this is done in the STG once it receives the voices which were previously differentiated by the HG. Which voices can be comfortably moved to the background and which ones you want to pay attention to is determined by the STG..
- Heschl’s gyrus (HG): The first sorting phase is handled by this part of the auditory cortex. Researchers discovered that the Heschl’s gyrus (we’re just going to call it HG from here on out) was breaking down each individual voice, classifying them via unique identities.
When you begin to suffer from hearing problems, it’s harder for your brain to identify voices because your ears are missing specific wavelengths of sound (low or high, depending on your hearing loss). Your brain can’t assign separate identities to each voice because it doesn’t have enough data. It all blends together as a consequence (which means conversations will more difficult to understand).
A New Algorithm From New Science
It’s common for hearing aids to have features that make it less difficult to hear in a crowd. But hearing aid makers can now incorporate more of those natural functions into their algorithms because they have a greater idea of what the process looks like. As an example, hearing aids that do more to identify voices can assist the Heschl’s gyrus a little bit, resulting in a better ability for you to understand what your coworkers are saying in that loud restaurant.
Technology will get better at mimicking what takes place in nature as we discover more about how the brain really works in combination with the ears. And better hearing outcomes will be the result. That way, you can focus a little less on straining to hear and a little more on enjoying yourself.