Why can we listen to one person at a party?

THAT'S THE WHY:Sometimes parties can get a bit noisy, particularly if they are any good. Maybe the speakers are jumping, music is blaring and glasses are clinking. All around, people are chatting and laughing right next to you. Have you ever wondered why you can hold a conversation with just one person in all that din?

This is the so-called “cocktail party effect”, or selective attention, where our brains can focus on one source of sound while seemingly filtering out others.

Researchers have been long looking into the questions of how we segregate sounds from the mixture coming into the ear and focus attention on one source, or switch our attention between sources.

The problem is by no means solved, but a small study published in Nature last month suggests the incoming speech information has been filtered by the time it is represented in the brain’s cortex.

The researchers from the University of California, San Francisco, worked with three people who were undergoing brain surgery for severe epilepsy.

Each patient heard recordings of two people talking at the same time, but were asked to focus on only one person. Meanwhile, the researchers measured the activity of brain cells in a part of the brain involved in hearing, the auditory cortex.

What they found suggests that the brain patterns there represented the speech of the targeted speaker.

“The new findings show that the representation of speech in the cortex does not just reflect the entire external acoustic environment but instead just what we really want or need to hear,” says a release from the university.