Brain Fact: Your Brain Fills in What You Don't Actually Hear

Fagjun | Published 2017-03-11 06:26

Your brain helps you "hear" noise-obscured words in noisy environments.

Here's an interesting brain fact: your brain can help you understand what another person is saying even when it's too noisy to hear words clearly.

Imagine that you're in a crowded street, a noisy bar, or somewhere close to a very busy road. You're talking to someone, and the ambient noise is blocking out some of the words the other person is saying. Your brain is able to “predict” what the person is actually saying without you having to hear all the words. It inserts the missing pieces of a sentence and allows you to understand what is being said to you. The best part of all this is that you don't even realize that it's happening.

This phenomenon is called phonemic restoration effect. Another thing that's interesting about it is that is doesn't affect all humans in the same way. It affects adult males and females differently, but this distinction is not present in children. It also affects children aged five and older in the same way it affects adults. Scientists have wondered how this happens, but it seems that they have found an answer.

A study has found an explanation for the phonemic restoration effect. Researchers studied how human brains reacted to inaudible or near-inaudible words. They gathered a group of five participants and hooked their brains up to electrodes to monitor brain activity.

The next step was to play recordings of partially inaudible words. The participants heard recordings of words like “faster” and “factor”. They then heard recordings of the same words, but with the “s” and “c” sounds obscured by noise.

Brain Fact: The Brain Works in Surprising Ways

The electrodes were able to record how the brains of the participants reacted to the missing sounds. Researchers found that the brain is able to fill in the missing pieces in real time, as it was “hearing” the words. There was no need to fill in the blanks after the fact, which was surprising to the researchers. The brain behaved as if it clearly heard the missing sound.

Here's another brain fact: the regions of the brain involved with language are the frontal lobes. During their experiment, the researchers found that the inferior and superior frontal cortices are responsible for the phonemic restoration effect. When you're listening to someone or something, the interior frontal cortex predicts what you're about to hear. Right on its heels comes the superior frontal cortex, which processes the sounds you hear. Predicting what you're about to hear and processing the sounds in real time happen just a fraction of a second apart.

With these two cortices working together, the phonemic restoration effect is able to happen in real time. It's like you're actually hearing missing sounds, because your brain already has information on what the sounds may be.

The study shows how hard the brain works to enable us to adapt to certain situations. It also provides more evidence that the phonemic restoration effect does actually exist. We now have another piece of excellent insight into how the human brain processes information.

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