If you've ever had a friend or significant other get angry at you for completely missing something they said, it might not be your fault.
Concentrating on a visual task — like staring at a phone screen — can make us temporarily deaf to any normal volume noise around us, according to a new study published in the Journal of Neuroscience.
Our brains can only process so much information at once, so when we're absorbed in a visual task like using a computer, searching for directions, or reading, we sometimes fail to register sounds around us. That's why we might not hear someone who's trying to get our attention or tell us something.
We're not just ignoring the sound or filtering it out — we aren't hearing it at all. Some psychologists call this "inattentional deafness."
"Inattentional deafness is a common experience in everyday life, and now we know why," UCL Institute of Cognitive Neuroscience professor Nilli Lavie, who worked on the new research, said in a press release.
"For example, if you try to talk to someone who is focusing on a book, game or television program and don't receive a response, they aren't necessarily ignoring you, they might simply not hear you! This could also explain why you might not hear your train or bus stop being announced if you're concentrating on your phone, book, or newspaper," she added.
Lavie and a team of researchers got 13 volunteers to wear headphones that played random sounds at random times while they tried to complete a visual task: pressing a computer key when a certain letter appeared. Each volunteer was hooked up to a brain scanner during the experiment.
When the letter game was easy, the volunteers were still able to detect all the sounds. As the letter game got harder, the brain scans suggested that the volunteers were concentrating more on the visual task and that there was very little brain response to the sounds coming through the headphones. It's not that they were just ignoring the sound or filtering it out, an analysis of the scans seemed to indicate — they weren't hearing it at all.
The study was small, and doesn't precisely replicate real-life circumstances. But the evidence here builds on earlier research by Lavie and others. Inattentional blindness, where we look at things but do not actually see them if we're not paying attention, is a perceptual shortcoming that's long been established by psychologists. ("We can fail to perceive very major things going on right in front of our eyes," Brian Scholl, a Yale psychologist, explained to the journalist Siri Carpenter in 2001.)
Inattentional deafness sounds like a pretty harmless phenomenon, beyond possibly frustrating friends and significant others who are trying to talk to you.
However, Lavie pointed out in the release that there are situations in which inattentional deafness can actually be a big problem: A surgeon concentrating on an operation might not hear medical alarms going off, for example, and a pedestrian staring at a phone might not hear a bicycle bell. Previous research has found that many pilots don't notice audio alarms when they are dealing with difficult situation in the air.
Unfortunately there's not much we can do to correct this — humans are just bad at multitasking.
"Our study shows that is a limitation of our brain," Lavie told Tech Insider in an email.
The best strategy to avoid frustration, Lavie said, is to make sure you have someone's attention before speaking to them.
