Selective hearing is a phrase that frequently is used as a pejorative, an insult. Maybe you heard your mother accuse your father of having “selective hearing” when she believed he was ignoring her.
But in reality it takes an amazing act of teamwork between your ears and your brain to have selective hearing.
Hearing in a Crowd
This situation potentially feels familiar: you’ve had a long day at work, but your buddies all insist on going out to dinner. They choose the noisiest restaurant (because it’s trendy and the food is delicious). And you spend the entire evening straining your ears, working hard to follow the conversation.
But it’s tough, and it’s taxing. And it’s a sign of hearing loss.
You think, maybe the restaurant was simply too noisy. But… everyone else appeared to be having a great time. The only one 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? Just why is it that being able to hear in a crowd is so quick to go? The answer, according to scientists, is selective hearing.
Selective Hearing – How Does it Work?
The term “selective hearing” is a process that doesn’t even happen in the ears and is formally called “hierarchical encoding”. The majority of this process occurs in the brain. At least, that’s in accordance with a new study performed by a team from Columbia University.
Ears work just like a funnel which scientists have understood for quite a while: they compile all the signals and then send the raw information to your brain. In the auditory cortex the real work is then done. That’s the part of your gray matter that processes all those signals, interpreting sensations of moving air into identifiable sounds.
Because of significant research with MRI and CT scans, scientists have known for years that the auditory cortex plays a substantial role in hearing, but they were clueless with regards to what those processes actually look like. Scientists were able, by making use of unique research techniques on individuals with epilepsy, to get a better understanding of how the auditory cortex discerns voices in a crowd.
The Hearing Hierarchy
And here is what these intrepid scientists found out: the majority of the work performed by the auditory cortex to pick out specific voices is done by two different parts. And in noisy environments, they enable you to isolate and amplify specific voices.
- Superior temporal gyrus (STG): Eventually your brain will need to make some value based decisions and this is done in the STG once it receives the voices that were previously differentiated by the HG. The superior temporal gyrus determines which voices you want to focus on and which can be safely moved to the background.
- Heschl’s gyrus (HG): This is the region of the auditory cortex that deals with the first stage of the sorting process. Heschl’s gyrus or HG processes each unique voice and separates them into distinguishable identities.
When you start to suffer with hearing impairment, it’s more difficult for your brain to differentiate voices because your ears are missing particular 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. As a result, it all blurs together (which means discussions will harder to follow).
A New Algorithm From New Science
Hearing aids currently have features that make it less difficult to hear in loud situations. But hearing aid manufacturers can now integrate more of those natural functions into their algorithms because they have a better idea of what the process looks like. For example, you will have a greater capacity to hear and understand what your coworkers are talking about with hearing aids that assist the Heshl’s gyrus and do a little more to separate voices.
The more we find out about how the brain works, particularly in connection with the ears, the better new technology will be able to mimic what happens in nature. And that can result in better hearing success. That way, you can focus a little less on straining to hear and a little more on enjoying yourself.