Sometimes when an individual has a hard time hearing, somebody close to them insultingly says they have “selective hearing”. Perhaps you heard your mother accuse your father of having “selective hearing” when she suspected he was ignoring her.
But in reality it takes an incredible act of teamwork between your brain and your ears to have selective hearing.
The Difficulty Of Trying to Hear in a Crowd
Maybe you’ve encountered this situation before: you’ve been through a long day at work, but your buddies all insist on going out to dinner. And naturally, they want to go to 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. And it’s a sign of hearing loss.
You think, maybe the restaurant was just too loud. But… everyone else seemed to be having a fine go of it. You seemed like the only one having trouble. Which gets you thinking: Why do ears that have hearing impairment have such a hard time with the noise of a crowded room? Just why is it that being able to hear in a crowd is so quick to go? The solution, as reported by scientists, is selective hearing.
How Does Selective Hearing Function?
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. This process almost entirely occurs in your brain. At least, that’s in line with a new study carried out by a team from Columbia University.
Scientists have known for quite some time that human ears effectively work as a funnel: they send 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 brain that processes all those signals, translating impressions of moving air into identifiable sounds.
Just what these processes look like was still unknown in spite of the existing understanding of the role played by the auditory cortex in the hearing process. Scientists were able, by utilizing novel research techniques on individuals with epilepsy, to get a better picture of how the auditory cortex discerns voices in a crowd.
The Hierarchy of Hearing
And here is what these intrepid scientists found out: the majority of the work done by the auditory cortex to isolate particular voices is done by two separate parts. And in noisy situations, they enable you to separate and intensify specific voices.
- Heschl’s gyrus (HG): This is the part of the auditory cortex that manages the first phase of the sorting process. Researchers discovered that the Heschl’s gyrus (we’re just going to call it HG from now on) was processing each distinct voice, classifying them via individual identities.
- Superior temporal gyrus (STG): Eventually your brain needs to make some value based decisions and this happens in the STG once it receives the voices that were previously separated by the HG. The superior temporal gyrus determines which voices you want to pay attention to and which can be securely moved to the background.
When you have hearing impairment, your ears are lacking certain wavelengths so it’s more difficult for your brain to recognize voices (high or low, depending on your hearing loss). Your brain can’t assign individual identities to each voice because it doesn’t have enough data. As a result, it all blurs together (which makes discussions difficult to follow).
A New Algorithm From New Science
Hearing aids currently have functions that make it easier to hear in loud situations. But now that we understand what the basic process looks like, hearing aid manufacturers can integrate more of those natural functions into their instrument algorithms. As an example, you will have a better capacity to hear and understand what your coworkers are saying with hearing aids that assist the Heshl’s gyrus and do a little more to identify voices.
Technology will get better at mimicking what happens in nature as we learn more about how the brain functions in conjunction with the ears. And better hearing outcomes will be the outcome. That way, you can concentrate a little less on struggling to hear and a little more on enjoying yourself.