If you’re reading these words, it’s thanks to the brain’s impressive sound-processing abilities. Scientists have long known that the brain can pick out individual sounds from a noisy environment, an ability known as the “cocktail party effect”.
Now, research suggests that the brain actively timestamps the sounds it hears, creating a virtual recording of the auditory environment.
The findings, published in the journal Nature Neuroscience, could have implications for how we process and remember speech.
Previous research has shown that the brain can filter out irrelevant sounds, and that this ability improves with practice.
For the new study, researchers from the University of California, Berkeley, set out to see if the brain does more than just filter out noise.
To test this, the team used a technique known as auditory steady-state response (ASSR). This involves playing a tone at a frequency that the ear can hear, but the brain cannot consciously process.
At the same time, the researchers also played a series of spoken words.
The team found that when the words and tones were in sync, the brain was more likely to process the words.
However, when the tones and words were out of sync, the brain was less likely to process the words.
The findings suggest that the brain actively timestamps the sounds it hears, in order to create a virtual recording of the auditory environment.
This ability to timestamp sounds could help us to process and remember speech, the researchers say.
“Our findings suggest that the brain keeps track of the timing of sounds in order to create a virtual recording of the auditory environment,” says study author Robert Wilson.
“This could be important for speech perception and memory, because the brain may use the timing of sounds to help reconstruct the sequence of words that were spoken.”
The findings could also have implications for how we process music, the researchers say.
“The ability to timestamp sounds could also be important for rhythm perception in music,” says Wilson.
“The brain might use the timing of sounds to help track the beat, and this could be important for the way we enjoy music.”
Our brains automatically process the words we hear in order to understand them. This process is known as “time-stamping”. Time-stamping is when the brain associates certain sounds with certain meanings. For example, when we hear the sound “ba”, our brain automatically associates it with the concept of a ball. This allows us to understand the word “ball” without having to consciously think about it.
