Why Can’t I Hear in a Crowd?
Selective hearing is a term that usually gets tossed about as a pejorative, an insult. Maybe you heard your mother suggest that your father had “selective hearing” when she thought he was ignoring her.
But actually it takes an amazing act of teamwork between your brain and your ears to have selective hearing.
The Difficulty Of Trying to Hear in a Crowd
This scenario potentially feels familiar: you’re feeling tired from a long day at work but your friends all really would like to go out for dinner and drinks. They decide on the loudest restaurant (because it’s trendy and the food is delicious). 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.
Perhaps, you rationalize, the restaurant was simply too noisy. But… everyone else appeared to be having a great time. The only person who appeared to be having difficulty was you. So you begin to ask yourself: 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, according to scientists, is selective hearing.
Selective Hearing – How Does it Work?
The term “selective hearing” is a task that doesn’t even happen in the ears and is technically called “hierarchical encoding”. This process almost completely occurs in your brain. At least, that’s in line with a new study done by a team at Columbia University.
Scientists have recognized for quite some time that human ears essentially work like a funnel: they forward 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 gray matter that handles all those impulses, interpreting impressions of moving air into perceptible sounds.
Precisely what these processes look like was still unknown in spite of the established understanding of the role played by the auditory cortex in the process of hearing. Scientists were able, by making use of novel research techniques on people with epilepsy, to get a better picture of how the auditory cortex picks out voices in a crowd.
The Hierarchy of Hearing
And the facts they found follows: the majority of the work performed by the auditory cortex to pick out particular voices is performed by two separate parts. And in noisy conditions, they enable you to separate and amplify certain voices.
- Heschl’s gyrus (HG): This is the part of the auditory cortex that handles the first stage of the sorting process. Scientists observed that the Heschl’s gyrus (we’re simply going to call it HG from here on out) was processing each unique voice, classifying them into individual identities.
- Superior temporal gyrus (STG): The separated voices go from the HG to the STG, and it’s at this point 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.
When you start to suffer from hearing problems, it’s more difficult for your brain to distinguish voices because your ears are lacking particular wavelengths of sound (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. It all blends together as a result (which makes conversations tough to follow).
New Science = New Algorithm
It’s common for hearing aids to have functions that make it less difficult to hear in a crowd. But hearing aid makers can now incorporate 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 comprehend what your coworkers are talking about with hearing aids that help the Heshl’s gyrus and do a little more to distinguish voices.
The more we discover about how the brain works, especially in conjunction with the ears, the better new technology will be capable of mimicking what takes place in nature. And that can result in improved hearing success. Then you can concentrate a little more on enjoying yourself and a little less on straining to hear.