Holding a conversation in a noisy environment can be challenging, especially when there are multiple people speaking at once or loud music playing in the background.
Now a new study carried out by Israeli researchers from Bar-Ilan University shows exactly how the brain processes conversations that are happening simultaneously.
A very straightforward take-home from our work is that the brain basically has difficulty shutting up things in the background. We might still be able to do our tasks but there is going to be an internal cost to this because the brain is allocating resources to deal with the environment as well
According to Dr. Elana Zion Golumbic, who led the study and is a researcher at the university’s Gonda (Goldschmied) Multidisciplinary Brain Research Center, the findings demonstrated why it can be so difficult to concentrate in open office spaces where several people are talking simultaneously.
“A very straightforward take-home from our work is that the brain basically has difficulty shutting up things in the background,” Zion Golumbic told The Media Line. “We might still be able to do our tasks but there is going to be an internal cost to this because the brain is allocating resources to deal with the environment as well.
“If we want to be more productive or more effective, then quieter places would be more beneficial,” she said.
How the human brain manages to process multiple conversations simultaneously and filter out background noises is known as the cocktail party problem. For decades, cognitive neuroscientists have wondered how the brain knows which voice or sound to prioritize and which to ignore.
In their study, which was recently released in the journal eLife, researchers at Bar-Ilan University examined how task-irrelevant (or background) speech competes for the brain’s processing resources. They tested whether the mind identifies words and phrases from such speech linguistically, or whether they are simply interpreted as “acoustic noises” and effectively tuned out.
Being unable to focus on a conversation in a noisy environment does not only affect those with hearing difficulties or attention deficit disorders, however.
“The brain is getting all these signals from the environment and it has to choose,” Zion Golumbic explained. “That selection is a hard thing to do.”
To carry out the study, researchers used a machine known as a MEG (magnetoencephalography) scanner, which in Israel is only found at Bar-Ilan University. The machine allows researchers to investigate human brain activity in a noninvasive way.
Zion Golumbic and her team observed 30 participants’ brain activity as they listened to two sets of speech stimuli, each presented to a different ear. Listeners were instructed to focus on one of the speakers and told to ignore the other.
While participants were able to consciously block out the background conversation, scientists found that “the brain is processing those other conversations at a relatively high level, where it can extract meaning and structure from the other conversations.”
Specifically, the researchers discovered that the brain processed the background conversations at both the acoustic and linguistic levels, indicating that most of the background sound was not in fact being extensively filtered out.
“I think we were surprised by the results because there is a dogma in the field that you filter out the background conversations and you only process them as sounds but you don’t really understand them,” Zion Golumbic said. “Our study is one of the few to show positive examples that that’s not entirely the case. It speaks to the brain’s amazing capacity to deal with an abundance of information.”
As our understanding of the cocktail party problem deepens, cognitive neuroscientists hope that their findings will lead to offices and other spaces being better designed to attenuate background speech, thereby increasing focus, well-being and productivity.
The research could also aid with the design of smart assistive devices or other technological solutions to help individuals navigate noisy environments.
“It’s a situation that we’re all familiar with and we want to understand what’s going on in our brains,” Paz Har-shai Yahav, a Ph.D. student at Bar-Ilan University and lead author of the study, told The Media Line.
“The bigger picture is that we wish that one day this will lead to better attention [spans] and help people with attention difficulties,” she added.