Sometimes when an individual has a hard time hearing, someone close to them insultingly suggests they have “selective hearing”. Maybe you heard your mother suggest that your father had “selective hearing” when she thought he might be ignoring her.
But actually selective hearing is quite the talent, an impressive linguistic accomplishment executed by cooperation between your brain and ears.
Hearing in a Crowd
Maybe you’ve dealt with this situation 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 loudest restaurant (because they have amazing food and live entertainment). And you spend an hour and a half straining your ears, trying to follow the conversation.
But it’s very difficult and exhausting. This indicates that you might have hearing loss.
Maybe, you rationalize, the restaurant was simply too loud. But no one else appeared to be having difficulties. The only person who appeared to be having difficulty was you. So you begin to wonder: Why do ears with hearing impairment have such a difficult time with the noise of a packed room? It seems like hearing well in a crowd is the first thing to go, but why? Scientists have started to reveal the solution, and it all starts with selective hearing.
Selective Hearing – How Does it Work?
The term “selective hearing” is a process that doesn’t even occur in the ears and is technically called “hierarchical encoding”. This process almost exclusively takes place in your brain. At least, that’s in line with a new study performed by a team at Columbia University.
Ears work like a funnel which scientists have recognized for quite a while: they gather all the signals and then deliver the raw information to your brain. In the auditory cortex the real work is then accomplished. That’s the part of your gray matter that processes all those signals, translating impressions of moving air into perceptible sounds.
Exactly what these processes look like had remained a mystery despite the established knowledge of the role played by the auditory cortex in the process of hearing. Scientists were able, by making use of unique research techniques on people with epilepsy, to get a better understanding of how the auditory cortex discerns voices in a crowd.
The Hierarchy of Hearing
And the facts they found out follows: the majority of the work accomplished by the auditory cortex to pick out specific voices is accomplished by two separate regions. And in loud environments, they allow you to separate and enhance certain voices.
- Superior temporal gyrus (STG): Eventually your brain needs to make some value based decisions and this happens in the STG after it receives the voices which were previously differentiated by the HG. The superior temporal gyrus figures out which voices you want to pay attention to and which can be safely moved to the background.
- Heschl’s gyrus (HG): The first sorting phase is taken care of by this part of the auditory cortex. Scientists discovered that the Heschl’s gyrus (we’re simply going to call it HG from now on) was breaking down each individual voice, separating them via unique identities.
When you begin to suffer with hearing impairment, it’s more difficult for your brain to differentiate voices because your ears are missing particular wavelengths of sound (high or low, depending on your hearing loss). Your brain isn’t furnished with enough data to assign separate identities to each voice. As a result, it all blends together (which makes conversations tough to follow).
New Science = New Algorithm
Hearing aids currently have functions that make it less difficult to hear in noisy circumstances. But hearing aid manufacturers can now integrate more of those natural functions into their algorithms because they have a better concept of what the process looks like. As an example, you will have a better ability 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 occurs in nature as we uncover more about how the brain works in combination with the ears. And that can lead to improved hearing success. Then you can concentrate a little more on enjoying yourself and a little less on straining to hear.