Why Can’t I Hear in a Crowd?

Man can't hear in a crowded restaurant.

Sometimes when a person has a difficult time hearing, somebody close to them insultingly says they have “selective hearing”. When your mother used to accuse you of having “selective hearing,” she was suggesting that you paid attention to the part about going to the fair and (maybe deliberately) disregarded the part about doing your chores.

But actually selective hearing is quite the skill, an amazing linguistic accomplishment conducted by cooperation between your brain and ears.

The Stress Of Trying to Hear in a Crowd

Perhaps you’ve dealt with this scenario before: you’ve had a long day at work, but your buddies all insist on meeting up for dinner. And naturally, they want to go to the noisiest restaurant (because it’s popular and the food is the best in town). And you strain and struggle to follow the conversation for the entire evening.

But it’s challenging, and it’s taxing. This indicates that you could have hearing loss.

You think, maybe the restaurant was just too loud. 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 wonder: Why do ears with hearing impairment have such a difficult time with the noise of a crowded room? It seems as if hearing well in a crowd is the first thing to go, but what’s the reason? The answer, as reported by scientists, is selective hearing.

How Does Selective Hearing Work?

The phrase “selective hearing” is a process that doesn’t even occur in the ears and is formally called “hierarchical encoding”. This process almost completely takes place in your brain. At least, that’s according to a new study done by a team from Columbia University.

Scientists have recognized for quite some time that human ears basically work as a funnel: they compile all the signals and then forward 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 handles all those impulses, translating sensations of moving air into identifiable sounds.

Exactly what these processes look like had remained a mystery despite the established understanding of the role played by the auditory cortex in the process of hearing. Scientists were able, by utilizing unique research techniques on people with epilepsy, to get a better picture of how the auditory cortex discerns voices in a crowd.

The Hierarchy of Hearing

And the facts they found out are as follows: most of the work accomplished by the auditory cortex to isolate specific voices is accomplished by two different regions. And in loud conditions, they enable you to isolate and boost specific voices.

  • Heschl’s gyrus (HG): This is the part of the auditory cortex that deals with the first stage of the sorting routine. Scientists observed that the Heschl’s gyrus (we’re just going to call it HG from here on out) was breaking down each individual voice, classifying them via individual identities.
  • Superior temporal gyrus (STG): At some point your brain will need to make some value based choices and this happens in the STG once it receives the voices which were previously separated by the HG. Which voices can be safely moved to the background and which ones you want to pay attention to is figured out by the STG..

When you start to suffer from hearing problems, it’s more difficult for your brain to identify voices because your ears are missing particular wavelengths of sound (low or high, depending on your hearing loss). Your brain isn’t supplied with enough data to assign individual identities to each voice. As a result, it all blends together (which makes interactions difficult to follow).

A New Algorithm From New Science

It’s typical for hearing aids to come with functions that make it easier to hear in a crowded situation. But now that we know what the fundamental process looks like, hearing aid makers can integrate more of those natural operations into their device algorithms. For example, you will have a greater ability to hear and understand what your coworkers are saying with hearing aids that help the Heshl’s gyrus and do a little more to distinguish voices.

The more we learn about how the brain works, specifically in conjunction with the ears, the better new technology will be able to mimic what takes place in nature. And that can lead to better hearing success. Then you can focus a little more on enjoying yourself and a little less on straining to hear.

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