Sometimes when a person has a hard time hearing, someone close to them insultingly suggests they have “selective hearing”. Maybe you heard your mother accuse your father of having “selective hearing” when she believed he was ignoring her.
But actually it takes an incredible act of teamwork between your ears and your brain to have selective hearing.
Hearing in a Crowd
Maybe you’ve encountered this scenario before: you’ve had a long day at work, but your buddies all insist on going out to dinner. And of course, they want to go to the noisiest restaurant (because they have great food and live entertainment). And you strain and struggle to understand the conversation for over an hour and a half.
But it’s very difficult and exhausting. This indicates that you may have hearing loss.
Maybe, you rationalize, the restaurant was simply too noisy. But… everyone else appeared to be having a fine go of it. You seemed like the only one having difficulty. Which makes you think: Why do ears that have hearing impairment have such a difficult time with the noise of a crowded room? It seems as if hearing well in a crowded place is the first thing to go, but why? The solution, according to scientists, is selective hearing.
How Does Selective Hearing Function?
The scientific term for what we’re broadly calling selective hearing is “hierarchical encoding,” and it doesn’t happen in your ears at all. This process almost completely happens in your brain. At least, that’s according to a new study performed by a team at Columbia University.
Ears work just like a funnel which scientists have understood for quite a while: they send all of the raw data that they collect to your brain. In the auditory cortex the real work is then accomplished. That’s the part of your brain that handles all those signals, interpreting sensations of moving air into identifiable sounds.
Precisely what these processes look like was still unknown despite the established understanding of the role played by the auditory cortex in the process of hearing. Thanks to some unique research methods involving participants with epilepsy, scientists at Columbia were able to find out more about how the auditory cortex works in relation to discerning voices in a crowd.
The Hierarchy of Hearing
And the information they discovered follows: there are two parts of the auditory cortex that manage most of the work in helping you identify distinct voices. They’re what enables you to separate and amplify particular voices in noisy settings.
- Superior temporal gyrus (STG): The differentiated voices go from the HG to the STG, and it’s here that your brain starts to make some value distinctions. The superior temporal gyrus figures out which voices you want to give attention to and which can be confidently moved to the background.
- Heschl’s gyrus (HG): This is the region of the auditory cortex that handles the first stage of the sorting routine. Heschl’s gyrus or HG breaks down each unique voice and separates them into distinct identities.
When you begin to suffer with hearing impairment, it’s harder for your brain to distinguish voices because your ears are lacking certain wavelengths of sound (depending on your hearing loss it could be low or high frequencies). Your brain can’t assign individual identities to each voice because it doesn’t have enough information. It all blends together as a result (which makes discussions hard to follow).
A New Algorithm From New Science
It’s common for hearing aids to have functions that make it less difficult to hear in a crowd. But hearing aid manufacturers can now include 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 better capacity to hear and comprehend what your coworkers are saying with hearing aids that assist the Heshl’s gyrus and do a little more to identify voices.
The more we learn about how the brain works, especially in connection with the ears, the better new technology will be able to mimic what takes place in nature. And that can result in improved hearing outcomes. Then you can concentrate a little more on enjoying yourself and a little less on straining to hear.