Selective hearing is a term that commonly gets tossed about as a pejorative, an insult. Maybe you heard your mother suggest that your father had “selective hearing” when she thought he might be ignoring her.
But it turns out that selective hearing is quite the ability, an impressive linguistic accomplishment executed by teamwork between your ears and brain.
The Difficulty Of Trying to Hear in a Crowd
This situation potentially seems familiar: you’re feeling tired from a long day at work but your friends all really want to go out for dinner and drinks. They decide on the noisiest restaurant (because they have amazing food and live entertainment). And you spend an hour and a half straining your ears, attempting to follow the conversation.
But it’s very difficult and exhausting. And it’s a sign of hearing loss.
You think, perhaps the restaurant was simply too loud. But no one else seemed to be having difficulties. The only one who appeared to be having difficulty was you. Which makes you think: Why do ears that have hearing impairment have such a hard time with the noise of a packed room? Just why is it that being able to hear in a crowd is so quick to go? The answer, as reported by scientists, is selective hearing.
How Does Selective Hearing Function?
The phrase “selective hearing” is a process that doesn’t even happen in the ears and is scientifically known as “hierarchical encoding”. Most of this process happens in the brain. At least, that’s in line with a new study carried out by a team from Columbia University.
Ears work like a funnel as scientists have recognized for some time: they gather all the signals and then deliver the raw information to your brain. In the auditory cortex the real work is then done. That’s the part of your brain that handles all those signals, translating sensations of moving air into perceptible sounds.
Because of extensive research with CT and MRI scans, scientists have understood for years that the auditory cortex plays a substantial role in hearing, but they were stumped when it came to what those processes really look like. Thanks to some innovative research methods concerning participants with epilepsy, scientists at Columbia were able to learn more about how the auditory cortex works in relation to picking out voices in a crowd.
The Hierarchy of Hearing
And here’s what these intrepid scientists learned: most of the work done by the auditory cortex to pick out specific voices is done by two separate regions. And in noisy settings, they enable you to isolate and enhance specific voices.
- Heschl’s gyrus (HG): The first sorting stage is handled by this region of the auditory cortex. Scientists discovered that the Heschl’s gyrus (we’re just going to call it HG from now on) was processing each individual voice, classifying them via individual identities.
- Superior temporal gyrus (STG): The separated voices go from the HG to the STG, and it’s here that your brain begins to make some value distinctions. Which voices can be comfortably moved to the background and which ones you want to pay attention to is figured out by the STG..
When you have hearing problems, your ears are lacking particular wavelengths so it’s harder for your brain to distinguish voices (high or low, 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 makes conversations difficult to follow).
New Science = New Algorithm
It’s common for hearing aids to come with features that make it less difficult to hear in a crowded situation. But now that we understand what the fundamental process looks like, hearing aid companies can incorporate more of those natural operations into their device algorithms. For instance, hearing aids that do more to identify voices can assist the Heschl’s gyrus a little, bringing about a better ability for you to comprehend what your coworkers are saying in that noisy restaurant.
The more we find out 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 better hearing success. Then you can focus a little more on enjoying yourself and a little less on straining to hear.