Many of us close our eyes in a noisy place while trying to focus on one sound. New research has found that closing your eyes has the opposite impact than people hope for. An experiment found that people had a harder time detecting faint background noises with their eyes closed.
The researchers used 52 study participants in a two-part study. First, they had 25 participants ID faint real-world noises masked by background noise. They had to try doing it with their eyes closed, open, open and looking at a still image or open and watching silent videos related to the sound. The second half of the test looked at the brain activity of 27 people listening to the sounds when they were played without being hidden to measure the mental effort it takes for the brain to process the noises.
The study found people were less able to hear faint noises with their eyes closed. When given visual cues, like an image or a video related to the sound, people had a much easier time hearing a noise. Brain activity also changed with closed-eyed listening. The brain moved into a different processing state that may filter out fainter sounds, turning them into just part of the noise.
“The key takeaway is: Forget the old wisdom,” says an author of the study, Dr. Yu Huang of Shanghai Jiao Tong Univ. “Whether you’re trying to detect a vehicle in traffic, or pick out a bird chirp in a windy park, opening your eyes will make your brain far better at picking out faint target sounds from background noise. Dynamic visual cues offer the biggest boost, but even just having your eyes open could help.”
For the next step in their research, the scientists want to study what happens when people are exposed to the wrong combinations of sights and sounds.
“Specifically, we want to test incongruent pairings — for example, what happens if you hear a drum but see a bird?” said Huang. “Does the visual boost come from simply having the eyes open and processing more visual information, or does the brain require the visual and audio information to match perfectly? Understanding this distinction will help us separate the general effects of attention from the specific benefits of multisensory integration.”
But the belief that closing your eyes to increase auditory sensitivity isn’t totally misplaced. There is still a place for closing your eyes to hear better. If you are in a quiet place, closing your eyes to focus on one sound does work. In loud situations, where hearing is hard, your brain needs as many cues as it can to help process information. But in a quiet place, cutting out sight can help you focus more on just one sense.
Sometimes we like to share very practical blog advice. While this research can shed light on how the brain processes sound, for most of us, it has a far more practical takeaway. Keeping your eyes open may help you hear more. If you are trying to find a ringing cell phone in a bag filled with things in a busy store, with a crying child next to you, closing your eyes to listen for your phone to find it won’t help. But if you are sitting by a still lake listening to birds calling, closing your eyes and listening might help you figure out what direction the birds are calling from.
