Man can't hear in a crowded restaurant.

Sometimes when a person has a hard time hearing, somebody close to them insultingly says they have “selective hearing”. Maybe you heard your mother accuse your father of having “selective hearing” when she suspected he might be ignoring her.

But it turns out that selective hearing is quite the talent, an amazing linguistic task conducted by teamwork between your ears and brain.

Hearing 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. And naturally, they want to go to the noisiest restaurant (because they have amazing food and live entertainment). And you strain and struggle to follow the conversation for the entire evening.

But it’s very difficult and exhausting. This suggests that you may have hearing loss.

Perhaps, you rationalize, the restaurant was simply too loud. But no one else appeared to be struggling. The only person who appeared to be having trouble was you. 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 challenging? The solution, according to scientists, is selective hearing.

Selective Hearing – How Does it Work?

The scientific name for what we’re broadly calling selective hearing is “hierarchical encoding,” and it doesn’t take place in your ears at all. The majority of this process occurs in the brain. At least, that’s according to a new study carried out by a team from Columbia University.

Scientists have recognized for quite a while that human ears basically work as a funnel: they collect all the impulses and then forward the raw data to your brain. That’s where the real work happens, particularly the auditory cortex. Vibrations caused by moving air are interpreted by this portion of the brain into perceptible sound information.

Because of significant research with CT and MRI scans, scientists have recognized for years that the auditory cortex plays a considerable role in hearing, but they were stumped when it came to what those processes actually look like. Thanks to some novel research techniques concerning participants with epilepsy, scientists at Columbia were able to discover more about how the auditory cortex functions in relation to discerning voices in a crowd.

The Hierarchy of Hearing

And here’s what these intrepid scientists learned: the majority of the work performed by the auditory cortex to pick out particular voices is accomplished by two separate parts. They’re what enables you to separate and intensify distinct voices in noisy environments.

  • Heschl’s gyrus (HG): This is the region of the auditory cortex that deals with the first stage of the sorting routine. Heschl’s gyrus or HG processes each unique voice and separates them into distinct identities.
  • Superior temporal gyrus (STG): Sooner or later your brain will need to make some value based choices 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 confidently moved to the background.

When you have hearing problems, your ears are lacking certain wavelengths so it’s more difficult for your brain to differentiate voices (low or high, based upon your hearing loss). Your brain isn’t furnished with enough data to assign separate identities to each voice. It all blends together as a consequence (which makes interactions difficult to follow).

New Science = New Algorithm

It’s common for hearing aids to come with features that make it less difficult to hear in a crowded situation. But hearing aid makers can now integrate more of those natural functions into their algorithms because they have a greater idea of what the process looks like. For instance, hearing aids that do more to differentiate voices can help out the Heschl’s gyrus a little bit, leading to a greater ability for you to comprehend what your coworkers are saying in that loud restaurant.

Technology will get better at mimicking what occurs in nature as we discover more about how the brain works in combination with the ears. 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.