If you have ever felt like you are in two minds about something then, it turns out, so do your ears.
A study by Trinity College Dublin researchers shows how people are capable of the ultimate eavesdropping skill: following two conversations at once for brief periods.
But it has nothing to do with having good hearing, for it is down to the brain’s capacity to process overlapping sounds.
The Trinity research found that for just a second or two the brain can begin fully following a new conversation without disengaging from the previous one.
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“The findings challenge the long-held view that we can only focus on one speaker at a time,” the authors said.
Their study, published in the international journal PLOS Biology, used electrodes attached to participants’ scalps to measure the activity in their brains that indicate communication between brain cells.
They were tasked with listening to two people talking simultaneously against a background of simulated crowd noise.
Participants were asked to switch their attention between the speakers while the researchers tracked how their brains responded through the signals detected by the electrodes.
Up to now, studies using this “cocktail party” technique focused on how the brain managed the impressive feat of sustaining attention on a speaker against a background of competing conversations.
But the Trinity study focused on attention-switching and found the brain was able to begin focusing on the new speaker while still engaged with the first – although not everyone was able to hold on equally strongly to both conversations.
“Our findings suggest that some people may naturally be better multitaskers than others, allowing them to better explore what’s happening around them without immediately losing focus on their current conversation,” said Prof Giovanni Di Liberto from the Trinity College Institute of Neuroscience.
“This could help explain why some people seem especially good at navigating busy social environments.
“Because this brief ‘dual-tracking’ ability seems to differ from person to person, it potentially gives some individuals an advantage in situations where rapidly shifting attention is valuable.”
While the study reveals more about brain function than about hearing, the research team believe it could lead the way to better technologies for people with impaired hearing.
Those could include smarter hearing aids that help users not only to focus on one speaker but also manage the wider sound environment more naturally.
“It could also improve understanding of why some people, including older adults and those with hearing difficulties, find busy places such as restaurants, workplaces and family gatherings particularly exhausting,” it said.
“Ultimately, the work offers fresh insight into one of the brain’s most impressive everyday skills: helping us stay engaged in one conversation while remaining ready to respond when something more important catches our ear.”
